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Sample records for detritiation system catalyst

  1. Development of a polymer catalyst for HANARO detritiation

    International Nuclear Information System (INIS)

    Chung, H.; Kang, H.S.; Paek, S.W.; Yoo, J.H.; Shon, S.H.; Kim, K.R.; Lee, S.H.; Ahn, D.H.; Lee, H.S.

    1998-01-01

    The use of heavy water as a reflector in HANARO results in the continuous exposure of deuterium oxide to neutron flux. Substantial quantities of tritium are generated by neutron activation of deuterium in the reflector. Airborne emissions and staff internal radiation doses could be caused by tritiated heavy water escaping from the system. A detritiation facility is thought to be effective in reducing the overall radiological impact. The detritiation process may consist of a catalytic exchange in the front-end and a cryogenic deuterium distillation section. In this paper, the catalyst manufacturing and its performance evaluation technology was presented. The waterproof polymer catalyst has a specific surface area larger than 400m 2 /g. It showed a high reaction rate in the hydrogen isotope exchange reaction. (author)

  2. Water detritiation: better catalysts for liquid phase catalytic exchange

    International Nuclear Information System (INIS)

    Braet, J.

    2005-01-01

    Fusion reactors are our hope for a clean nuclear energy. But as they shall handle huge amounts of tritium, 1.5 10 19 Bq GWth -1 a -1 or about 50 000 times more tritium than light water fission reactors, they need detritiation. Most tritium losses can be trapped as or can easily be transformed into tritiated water. Water detritiation is preferably based on the multiplication of the large equilibrium isotope effect during the exchange reaction of tritium between hydrogen gas and liquid water in a counter current trickle bed reactor. Such LPCE (Liquid Phase Catalytic Exchange) requires an efficient hydrophobic catalyst. SCK-CEN invented and developed such a catalyst in the past. In combination with an appropriate packing, different batches of this catalyst performed very well during years of extensive testing, allowing to develop the ELEX process for water detritiation at inland reprocessing plants. The main objectives of this study were to reproduce and possibly improve the SCK-CEN catalyst for tritium exchange between hydrogen and liquid water; and to demonstrate the high overall exchange rate and thus high detritiation factors that can be realized with it in a small and simple LPCE column under typical but conservative operating conditions

  3. Development of Water Detritiation Process Using the Hydrophobic Platinum Catalyst

    International Nuclear Information System (INIS)

    Ahn, D.H.; Paek, S.; Choi, H.J.; Kim, K.R.; Chung, H.; Yim, S.P.; Lee, M.S.

    2006-01-01

    Radioactive emissions and occupational doses by tritium are mainly caused by tritiated water escaping from equipment in the nuclear industry. Improving the leak-tightness of equipment is effective in reducing emissions and internal dose but is not a long-term solution. Water detritiation was consider to be the most effective tritium control option since tritium is removed right from the source. The WTRF (Wolsong Tritium Removal Facility) is under construction now with the completion date of June, 2006 in Korea. It is designed to remove tritium from tritiated heavy water in each of the existing four Candu units at Wolsong site. We developed a hydrophobic platinum catalyst (Pt/SDBC catalyst) that would be used at the LPCE (Liquid Phase Catalytic Exchange) column in the WTRF. The catalytic rate constants of the newly developed catalyst for the deuterium exchange reaction between water vapor and hydrogen gas were measured in a recycle reactor. The catalytic rate constants of the Pt/SDBC catalyst decreased with reaction time and were much greater than that required, 2.0 x 10 -4 mol (D 2 )/s/g(pellet) in the design of the WTRF. Tritium removal efficiency of the WTRF, which is important for a safe and reliable operation of the facility, depends on the design and operating variables. A theoretical model based on the design and operating variables of the LPCE process was set up, and the equations between the parameters were derived. Numerical calculation result from a computer program shows steep increase of the detritiation factor of the LPCE process with respect to temperature increase and mild increase with respect to pressure decrease. The other parametric study shows that the calculated detritiation factors increase as the catalyst efficiency, number of theoretical stages of hydrophilic packing, the detritiation factor of cryogenic distillation system and the total number of sections increase. We also proceeded with the experiments for the hydrogen isotopic exchange

  4. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.

    1989-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10/sup 7/ was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H/sub 2/O to the stream entering the molecular sieve and premoistening of the sieve with H/sub 2/O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled

  5. Atmospheric detritiation system performance

    International Nuclear Information System (INIS)

    Longhurst, G.R.; Jalbert, R.A.; Rossmassler, R.L.; Los Alamos National Lab., NM; Princeton Univ., NJ

    1988-01-01

    An investigation of the performance of atmospheric detritiation systems and of possible ways for improving their performance was undertaken. Small-scale experiments demonstrated that system performance is strongly dependent on catalyst bed temperature. That may be helped by addition of protium to the process gas stream, but added protium at constant temperature does not increase conversion to HTO. Collection of the HTO on dry sieve with residual HTO fraction of less than one part in 10 7 was observed. Ways suggested for improvement in collection of HTO on molecular sieve beds include adding H 2 O to the stream entering the molecular sieve and premoistening of the sieve with H 2 O. While these improvement schemes may reduce HTO emissions they increase the amount of tritiated waste that must be handled. 13 refs., 4 figs

  6. Recent activities on water detritiation technology in JAEA

    Energy Technology Data Exchange (ETDEWEB)

    Iwai, Yasunori, E-mail: iwai.yasunori@jaea.go.jp [Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Kubo, Hitoshi; Ohshima, Yusuke; Noguchi, Hiroshi; Taniuchi, Junichi [Tanaka Kikinzoku Kogyo K.K., Wadai, Tsukuba, Ibaraki 300-4247 (Japan)

    2016-11-01

    Highlights: • Water detritiation technology has been developed for the Japanese fusion DEMO plant. • Durability of an ion exchange membrane was checked with concentrated tritiated water. • Hydrophobic catalyst of SiO{sub 2} substrate has been developed for water detritiation. - Abstract: Japan Atomic Energy Agency has developed the water detritiation technology for CECE process considering the escalation in quantity and tritium concentration of tritiated water to be processed toward realization of the Japanese fusion DEMO plant. A commercial ion exchange perfluoro-membrane for concentrated tritiated water electrolyzer is durable against irradiation up to 1500 kGy in view of mechanical strength and ion exchange capacity. Concerning hydrophobic catalyst for LPCE column, a new method of manufacturing catalysts involving hydrophobic processing with an inorganic substance base has been developed. The catalyst created with this method has achieved the highest exchange efficiency, equivalent to 1.3 times the previously most powerful efficiency.

  7. Influence on moisture and hydrocarbons on conversion rate of tritium in catalytic reactors of fusion-DEMO detritiation system

    International Nuclear Information System (INIS)

    Edao, Yuki; Sato, Katsumi; Iwai, Yasunori; Hayashi, Takumi

    2017-01-01

    Thoughtful consideration of abnormal events such as fire is required to design and qualify a detritiation system (DS) of a nuclear fusion facility. Since conversion of tritium to tritiated vapor over catalyst is the key process of the DS, it is indispensable to evaluate the effect of excess moisture and hydrocarbons produced by combustion of cables on tritium conversion rate considering fire events. We conducted demonstration tests on tritium conversion under the following representative conditions: (I) leakage of tritium, (II) leakage of tritium plus moisture, and (III) leakage of tritium plus hydrocarbons. Detritiation behavior in the simulated room was assessed, and the amount of catalyst to fulfill the requirement on tritium conversion rate was evaluated. The dominant parameters for detritiation are the concentration of hydrogen in air and catalyst temperature. The tritium in the simulated room was decreased for condition (I) following ventilation theory. An initial reduction in conversion rate was measured for condition (II). To recover the reduction smoothly, it is suggested to optimize the power of preheater. An increase in catalyst temperature by heat of reaction of hydrocarbon combustion was evaluated for condition (III). The heat balance of catalytic reactor is a point to be carefully investigated to avoid runaway of catalyst temperature. (author)

  8. Development of the ELEX process for water detritiation

    International Nuclear Information System (INIS)

    Bruggeman, A.; Meynendonckx, L.; Parmentier, C.; Goossens, W.R.A.; Baetsle, L.H.

    1984-01-01

    The ELEX process which appears to be very suitable for the detritiation of CTR cooling water and wastewater, is based on the electrolysis of water and the catalytic exchange of tritium between hydrogen and water. The exchange is carried out in a simple countercurrent packed-bed reactor and it is promoted by a proprietary hydrophobic catalysts. After a study of the single constituent steps with a.o. the development of an appropriate hydrophobic catalyst, the integrated ELEX process was successfully demonstrated by detritiating more than 1000 dm 3 water in a 0.18 dm 3 h -1 bench-scale installation. (author)

  9. Catalytic detritiation of water

    International Nuclear Information System (INIS)

    Rogers, M.L.; Lamberger, P.H.; Ellis, R.E.; Mills, T.K.

    1977-01-01

    A pilot-scale system has been used at Mound Laboratory to investigate the catalytic detritiation of water. A hydrophobic, precious metal catalyst is used to promote the exchange of tritium between liquid water and gaseous hydrogen at 60 0 C. Two columns are used, each 7.5 m long by 2.5 cm ID and packed with catalyst. Water flow is 5-10 cm 3 /min and countercurrent hydrogen flow is 9,000-12,000 cm 3 /min. The equipment, except for the columns, is housed in an inert atmosphere glovebox and is computer controlled. The hydrogen is obtained by electrolysis of a portion of the water stream. Enriched gaseous tritium is withdrawn for further enrichment. A description of the system is included along with an outline of its operation. Recent experimental data are discussed

  10. Prototype scale demonstration of CECE detritiation

    International Nuclear Information System (INIS)

    Sadhankar Ramesh; Cobanoglu, Macit

    2004-01-01

    AECL has developed and demonstrated the Combined Electrolysis and Catalytic Exchange (CECE) Process for detritiation of heavy water. Although CECE has been the subject of pilot-scale demonstrations by various organizations, AECL is the first to demonstrate this technology in an industrial prototype plant. AECL designed, built and operated a CECE demonstration facility under CAN/CSA N286 Quality Assurance Program. The facility was licensed by the Canadian nuclear regulator. This was a two-fold demonstration of the CECE technology - for upgrading (removal of light water) and for detritiation of heavy water. In 1998 June, AECL began operating the facility in upgrading mode. The design feed rate ranged up to 25 Mg/a for 95 mol% D 2 O feed water. After 18 months of operation in upgrading mode, the facility was reconfigured and operated for an additional 9 months from 2000 August in detritiation mode. Design capacity for detritiation was 5 Mg/a with a detritiation factor (DF) of 100. However, significantly higher DFs, up to 56 000, were demonstrated. Highlights of the detritiation demonstration were: Proven robustness of AECL's proprietary wetproofed catalyst for Liquid Phase Catalytic Exchange; Demonstration of a trickle-bed-recombiner for stoichiometric combination of deuterium and oxygen; Demonstration of electrolysis of highly tritiated heavy water; High process availability and controllability was demonstrated by a long interrupted run; Low emissions; Demonstration of high DF - up to 56 000 - a significant advantage of the CECE process over other approaches to detritiation; Validation of AECL's simulation code for the CECE process over a range of DFs from 100 to 50 000. Apart from the technology, AECL has expertise in all aspects of setting up a new detritiation facility including design, engineering, safety assessment, licensing support, project management and training. AECL is also the engineering and design contractor for a tritium removal facility that is under

  11. CANDU design options with detritiation

    International Nuclear Information System (INIS)

    Wren, D.J.; Hart, R.S.

    1997-01-01

    CANDU reactors include a number of auxiliary systems to manage the inventory, purification, clean-up and isotopic purity of the heavy water used in the moderator and heat transport system. These systems are designed and installed to treat the moderator and heat transport water in separate parallel systems. One of the reasons for this parallel approach to heavy water management is the tritium inventory in the heavy water. Different levels of tritium accumulate in the moderator and heat transport system during reactor operation, with the moderator water having a much higher tritium concentration. Strict separation of the high- tritium-concentration moderator water from the low-tritium-concentration heat transport system water is an integral component of the CANDU design and operating strategy to limit potential releases of tritium to the containment building atmosphere. AECL is developing a new cost-effective technology for the detritiation of heavy water based on the Combined Electrolysis and Catalytic Exchange (CECE) process. This detritiation technology has the potential to be integrated into the heavy water management systems of a CANDU reactor. On-line detritiation could be used to limit the concentration of tritium in the moderator and also to detritiate any water collected within the containment building from other sources. The availability of economic detritiation technology would provide a flexibility to redesign some of the auxiliary heavy water management systems. In particular, there is potential to eliminate some of the duplication in the current management systems and also reduce costs by reclassifying some reactor systems that would have lower maximum tritium concentrations. This paper discusses some of the advantages of detritiation and some of the conceptual design options that detritiation would provide. The goal would be to lower the overall reactor cost with detritiation, but it is premature to assess whether this goal can be achieved. (author)

  12. Separation setup for the light water detritiation process in the water-hydrogen system based on the membrane contact devices

    International Nuclear Information System (INIS)

    Rozenkevich, M. B.; Rastunova, I. L.; Prokunin, S. V.

    2008-01-01

    Detritiation of light water wastes down to a level permissible to discharge into the environment while simultaneously concentrating tritium to decrease amount of waste being buried is a constant problem. The laboratory setup for the light water detritiation process is presented. The separation column consists of 10 horizontally arranged perfluorosulphonic acid Nafion-type membrane contact devises and platinum catalyst (RCTU-3SM). Each contact device has 42.3 cm 2 of the membrane and 10 cm 3 of the catalyst. The column is washed by tritium free light water (L H2O ) and the tritium-containing flow (F HTO ) feeds the electrolyser at λ = G H2 /L H2O = 2. A separation factor of 66 is noted with the device at 336 K and 0.145 MPa. (authors)

  13. ITER task D316 (1996): design review of isotope separation system (WBS 3.2 B) and water detritiation system (WBS 3.2 E)

    International Nuclear Information System (INIS)

    Sood, S.K.; Fong, C.

    1997-05-01

    The design review performed on the ITER Isotope Separation System and the Water Detritiation System are summarized. The objectives of the task are: to produce a Design Description Document for the Feed Treatment and Vacuum system for the Water Detritiation system; to review the process system operation and control philosophy for the Water Detritiation System; to review the equipment arrangement drawings where available. 1 fig., 3 refs

  14. ITER SAFETY TASK NID-5D: Operational tritium loss and accident investigation for heat transport and water detritiation systems

    International Nuclear Information System (INIS)

    Kalyanam, K.M.; Fong, C.; Moledina, M.; Natalizio, A.

    1995-02-01

    The task objectives are to: a) determine major pathways for tritium loss during normal operation of the cooling systems and water detritiation system, b) estimate operational losses and environmental tritium releases from the heat transport and water detritiation systems of ITER, and c) prepare a preliminary Failure Modes and Effects Analysis (FMEA) for the ITER Water Detritiation System. The analysis will be used to estimate chronic environmental tritium releases (airborne and waterborne) for the ITER Cooling Systems and Water Detritiation System. The assessment will form the basis for demonstrating the acceptability of ITER for siting in the Early Safety and Environmental Characterization Study (ESECS), to be issued in early 1995. (author). 7 refs., 10 tabs., 11 figs

  15. Conceptual design and optimization for JET water detritiation system cryo-distillation facility

    International Nuclear Information System (INIS)

    Lefebvre, X.; Hollingsworth, A.; Parracho, A.; Dalgliesh, P.; Butler, B.; Smith, R.

    2015-01-01

    The aim of the Exhaust Detritiation System (EDS) of the JET Active Gas Handling System (AGHS) is to convert all Q-based species (Q 2 , Q-hydrocarbons) into Q 2 O (Q being indifferently H, D or T) which is then trapped on molecular sieve beds (MSB). Regenerating the saturated MSBs leads to the production of tritiated water which is stored in Briggs drums. An alternative disposal solution to offsite shipping, is to process the tritiated water onsite via the implementation of a Water Detritiation System (WDS) based, in part, on the combination of an electrolyser and a cryo-distillation (CD) facility. The CD system will separate a Q 2 mixture into a de-tritiated hydrogen stream for safe release and a tritiated stream for further processing on existing AGHS subsystems. A sensitivity study of the Souers' model using the simulation program ProSimPlus (edited by ProSim S.A.) has then been undertaken in order to perform an optimised dimensioning of the cryo-distillation system in terms of available cooling technologies, cost of investment, cost of operations, process performance and safety. (authors)

  16. Conceptual design and optimization for JET water detritiation system cryo-distillation facility

    Energy Technology Data Exchange (ETDEWEB)

    Lefebvre, X.; Hollingsworth, A.; Parracho, A.; Dalgliesh, P.; Butler, B.; Smith, R. [JET-EFDA, Culham Science Center, Abingdon, Oxon (United Kingdom)

    2015-03-15

    The aim of the Exhaust Detritiation System (EDS) of the JET Active Gas Handling System (AGHS) is to convert all Q-based species (Q{sub 2}, Q-hydrocarbons) into Q{sub 2}O (Q being indifferently H, D or T) which is then trapped on molecular sieve beds (MSB). Regenerating the saturated MSBs leads to the production of tritiated water which is stored in Briggs drums. An alternative disposal solution to offsite shipping, is to process the tritiated water onsite via the implementation of a Water Detritiation System (WDS) based, in part, on the combination of an electrolyser and a cryo-distillation (CD) facility. The CD system will separate a Q{sub 2} mixture into a de-tritiated hydrogen stream for safe release and a tritiated stream for further processing on existing AGHS subsystems. A sensitivity study of the Souers' model using the simulation program ProSimPlus (edited by ProSim S.A.) has then been undertaken in order to perform an optimised dimensioning of the cryo-distillation system in terms of available cooling technologies, cost of investment, cost of operations, process performance and safety. (authors)

  17. Design of water detritiation system for fusion reactor

    International Nuclear Information System (INIS)

    Xie Bo; Wang Heyi; Liu Yunnu; Guan Rui

    2006-01-01

    The water detritiation system (WDS) of tritium plant for the International Thermonuclear Experimental Reactor (ITER) was designed. The concept of the Combined Electrolysis Catalytic Exchange and Gas Chromatography (CECE-GC) process was selected for the system and subsystems' descriptions of the WDS. ITER-WDS is characterised from the present demonstration system by rejecting the use of a recombiner and alkali electrolyzer, but a solid polymer electrolyzer (SPE) and a Pd/Ag membrane permeator system are adopted to recover tritium. (authors)

  18. Development of a water detritiation facility for JET

    International Nuclear Information System (INIS)

    Perevezentsev, A.N.; Bell, A.C.; Brennan, P.D.; Hemmerich, J.L.

    2002-01-01

    A water detritiation facility, based on a world-wide adopted combined electrolysis catalytic exchange (CECE) process, for the JET active gas handling plant is described. A research and development programme is presented. The programme includes the testing of structured inert packing with an incorporated hydrophobic catalyst for increased throughput of a liquid phase catalytic exchange (LPCE) column, a vapour phase catalytic exchange (VPCE) process for reduction of tritium inventory in the alkali electrolyser and a column of high effectiveness for alkali retention

  19. Enhanced configuration of a water detritiation system; impact on ITER Isotope Separation System based cryogenic distillation

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, Ion, E-mail: ion.cristescu@kit.edu

    2016-11-01

    Highlights: • An enhanced configuration of ITER WDS has been developed. • The proposed configuration allows minimization of hazards due to the reduction of tritium inventory. • The load on the tritium recovery system (ITER ISS) is minimized with benefits on mitigation of the explosion hazards. - Abstract: Tritiated water is generated in the ITER systems by various sources and may contain deuterium and tritium at various concentrations. The reference process for the ITER Water Detritiation System is based on Combined Electrolysis Catalytic Exchange (CECE) configuration. During long time operation of the CECE process, the accumulation of deuterium in the electrolysis unit and consequently along the Liquid Phase Catalytic Exchange (LPCE) column is unavoidable with consequences on the overall detritiation factor of the system. Beside the deuterium issue in the process, the large amount of the tritiated water with tritium activity up to 500 Ci/kg in the electrolysis cells is a concern from the safety aspect of the plant. The enhanced configuration of a system for processing tritiated water allows mitigation of the effects due to deuterium accumulation and also reduction of tritium inventory within the electrolysis system. In addition the benefits concerning to the interface between the water detritiation system and tritium recovery based cryogenic distillation are also presented.

  20. Development and Improvement of Devices for Hydrogen Generation and Oxidation in Water Detritiation Facility Based on CECE Technology

    International Nuclear Information System (INIS)

    Rozenkevich, M.; Andreev, B.; Magomedbekov, E.; Park, Yu.; Sakharovsky, Yu.; Perevezentsev, A.

    2005-01-01

    Water detritiation facility based on CECE (Combined Electrolysis and Catalytic Exchange) technology needs an electrolyser for water conversion to hydrogen. Use of a conventional alkali electrolyser requires a very deep purification of hydrogen stream from alkali prior to injection to LPCE (Liquid Phase Catalytic Exchange) column. In some applications conversion of detritiated hydrogen back into water is required. This is usually performed via hydrogen catalytic oxidation in a recombiner. This paper presents results of study to improve hydrogen and oxygen purification for alkali electrolysers and develop a hydrogen recombiner based on use of hydrophobic catalyst

  1. Glovebox atmosphere detritiation process using gas separation membranes

    International Nuclear Information System (INIS)

    Le Digabel, M.; Truan, P.A.; Ducret, D.; Laquerbe, C.; Perriat, P.; Niepce, J.C.; Pelletier, T.

    2003-01-01

    The use of gas separation membranes in atmospheric detritiation systems has been studied. The main advantage of this new process is to reduce the number and/or the size of the equipment in comparison to conventional tritium removal systems. Owing to the constraints linked to tritium handling, the separation performances of several commercial hollow fiber organic membranes have been analyzed, under various operating conditions, with hydrogen/nitrogen or deuterium/nitrogen mixtures. The experiments are performed with small quantities of hydrogen or deuterium (5000 ppm). The experimental results allow to evaluate the separation efficiency of these membranes and to determine the appropriate operating conditions to apply to a membrane detritiation process

  2. Detritiation studies for JET decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Perevezentsev, A.N.; Bell, A.C.; Williams, J.; Brennan, P.D. [EURATOM/UKAEA Fussion Association, Culham Science Centre, Abingdon (United Kingdom)

    2007-07-01

    JET is the world largest tokamak and has the capacity of operating with a tritium plasma. Three experimental campaigns, the Preliminary Tritium Experiment (0.1g T{sub 2}) in 1991, the Trace Tritium Experiment (5g T{sub 2}) in 2005, and the large experiment, the Deuterium-Tritium Experiment (DTE1) (100g T{sub 2}) in 1997, were carried out at JET with tritium plasmas. In DTE1 about 35 grams of tritium were fed directly into the vacuum vessel, with about 30% of this tritium being retained inside the vessel. In several years time JET will cease experimental operations and enter a decommissioning phase. In preparation for this the United Kingdom Atomic Energy Authority, the JET Operator, has been carrying out studies of various detritiation techniques. The materials which have been the subject of these studies include solid materials, such as various metals (Inconel 600 and 625, stainless steel 316L, beryllium, 'oxygen-free' copper, aluminium bronze), carbon fibre composite tiles, 'carbon' flakes and dust present in the vacuum vessel and also soft housekeeping materials. Liquid materials include organic liquids, such as vacuum oils and scintillation cocktails, and water. Detritiation of gas streams was also investigated. The purpose of the studies was to select and experimentally prove primary and auxiliary technologies for in-situ detritiation of in-vessel components and ex-situ detritiation of components removed from the vessel. The targets of ex-vessel detritiation were a reduction of the tritium inventory in and the rate of tritium out-gassing from the materials, and conversion, if possible, of intermediate level waste to low level waste and a reduction in volume of waste for disposal. The results of experimental trials and their potential application are presented. (orig.)

  3. Safety system in a heavy water detritiation plant

    International Nuclear Information System (INIS)

    Balteanu, O.; Stefan, I.; Retevoi, C.

    2003-01-01

    In a CANDU 6 type reactor a quantity of 55·10 15 Bq/year of tritium is generated, 95% being in the D 2 O moderator which can achieve a radioactivity of 2.5-3.5·10 12 Bq/kg. Tritium in heavy water contributes with 30-50% to the doses received by operation personnel and up to 20% to the radioactivity released in the environment. The large quantity of heavy water used in this type of reactors (500 tones) make storage very difficult, especially for environment. The extraction of tritium from tritiated heavy water of CANDU reactors solve the following problems: the radiation level in the operation area, the costs of maintenance and repair reduction due to reduction of personnel protection measures, the increase of NPP utilisation factor by shutdown time reduction for maintenance and repair, use the extracted tritium for fusion reactors and not for the last, lower costs and risk for storage heavy water waste. Heavy water detritiation methods, which currently are used in the industrial or experimental plant, are based on catalytic isotope exchange or electrolysis followed cryogenic distillation or permeation. The technology developed at Institute of Cryogenics and Isotope Separation is based upon catalytic exchange between tritiated water and deuterium, followed by cryogenic distillation of hydrogen isotopes. The nature of the fluids that are processed in detritiation requires the operation of the plant in safety conditions. The paper presents the safety system solution chose in order to solve this task, as well as a simulation of an incident and safety system response. The application software is using LabView platform that is specialised on control and factory automation applications. (author)

  4. Advanced air detritiation dryer

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    The isotopic exchange principle has proved effective in increasing air detritiation factors of atmospheric dryers. A CFFTP/AECL Chalk River program has demonstrated detritiation factors of 100,000 in trials. The technology is designed for application on regenerating atmospheric dryers using molecular sieve desiccant beds, used in rooms likely to encounter airborne tritium contamination. Dryer design concepts for dryers at JET (Joint European Torus, England) and ITER have been prepared by Alan Dombra of AECL, using the isotopic exchange technology. The isotopic exchange method works by passing tritiated air over a detritiated desiccant bed. Airborne tritium atoms are exchanged in the bed for ordinary hydrogen atoms from the bed's residual moisture loading. Tritium remains on the bed until it is discharged in a regeneration cycle. During regeneration, the desiccant bed is first heated with hot, dry air to drive off collected tritiated moisture. Airborne tritium removed from the air is collected as a tritiated water distillate and stored for later processing. During the second part of the regeneration cycle, the desiccant bed is washed with clean moist air to elute remaining traces of tritium and to refresh the bed to ready it for another tritium absorption period

  5. A light-water detritiation project at Chalk River Laboratories

    International Nuclear Information System (INIS)

    Boniface, H.A.; Castillo, I.; Everatt, A.E.; Ryland, D.K.

    2010-01-01

    The NRU reactor rod bays is a large, open pool of water that receives hundreds of fuel rods annually, each carrying a small amount of residual tritiated heavy water. The tritium concentration of the rod bays water has risen over the years, to a level that is of concern to the operations staff and to the environment. The proposed long-term solution is to reduce the rod bays tritium concentration by direct detritiation of the water. The Combined Electrolytic-Catalytic Exchange (CECE) process is well suited to the light-water detritiation problem. With a tritium-protium separation factor greater than five, a CECE detritiation process can easily achieve the eight orders of magnitude separation required to split a tritiated light-water feed into an essentially tritium-free effluent stream and a tritiated heavy water product suitable for recycling through a heavy water upgrader. This paper describes a CECE light-water detritiation process specifically designed to reduce the tritium concentration in the NRU rod bays to an acceptable level. The conceptual design of a 600 Mg/a detritiation process has been developed and is now at the stage of project review and the beginning of detailed design. (author)

  6. Hydrogen isotope separation in hydrophobic catalysts between hydrogen and liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Linsen, E-mail: yls2005@mail.ustc.edu.cn [China Academy of Engineering Physics, Mianyang 621900 (China); Luo, Deli [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621907 (China); Tang, Tao; Yang, Wan; Yang, Yong [China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-11-15

    Hydrogen isotope catalytic exchange between hydrogen and liquid water is a very effective process for deuterium-depleted potable water production and heavy water detritiation. To improve the characteristics of hydrophobic catalysts for this type of reaction, foamed and cellular structures of hydrophobic carbon-supported platinum catalysts were successfully prepared. Separation of deuterium or tritium from liquid water was carried out by liquid-phase catalytic exchange. At a gas–liquid ratio of 1.53 and exchange temperature of 70 °C, the theoretical plate height of the hydrophobic catalyst (HETP = 34.2 cm) was slightly lower than previously reported values. Changing the concentration of the exchange column outlet water yielded nonlinear changes in the height of the packing layer. Configurations of deuterium-depleted potable water and detritiation of heavy water provide references for practical applications.

  7. Installing the detritiation facility at Cernavoda NPP. Technical solutions and national participation

    International Nuclear Information System (INIS)

    Barariu, Gheorghe

    2002-01-01

    Generation and accumulation almost linear of tritium in the heavy water used as moderator and coolant in CANDU type reactors appears to be a drawback with implication upon the long term operation of the nuclear station. In the CANDU type reactors about 2400 kCi/GW(e) of tritium is generated annually. In case of CANDU-600 reactors as, those operating at Cernavoda NPP, the amount of tritium generated is 1500 kCi/y from which about 95% is found in moderator water what leads to an activity level of about 80-100 Ci/kg. Due to the specific working conditions about 85 Mg/y of D 2 O are eliminated from the circuits of which some 95% is recovered. About 30-50% of the radiation dose to which the operation personnel is exposed is due to the tritium from heavy water, while its contribution to the radioactivity released in the environment is about 20%. Detritiation ensures a radioactivity level due to the tritium contained in the moderator heavy water of about 5 Ci/kg in D 2 O moderator and about 1 Ci/kg in the coolant. Consequently, the radiation dose due to tritium is reduced three times while the tritium amount released in the environment is diminished by about 10 times. At present, the price of tritium is 2-3 USD/Ci what means that the tritium recovered from a CANDU reactor could reach a value of about USD 3 - 4.5 million/y. The detritiation procedures are based on catalyzed chemical exchange, heavy water electrolysis and deuterium distillation. Following experimentations and cost/benefit analyses the Institute for Cryogenics and Isotopic Technologies, ICSI, at Rm. Valcea, adopted for detritiation the procedure LPCE - CD, i.e. Liquid Phase Catalytic Exchange - Cryogenic Distillation. The procedure allows tritium transfer from the heavy water in gaseous deuterium in a column equipped with hydrophobic catalyst and phosphorous bronze packing. In the second stage of the technological process, the tritium is extracted from the gaseous phase by liquid deuterium distillation and

  8. Detritiation plant of the Laue Longevin Institute

    International Nuclear Information System (INIS)

    Pautrot, P.; Arnaud, J.P.

    The detritiation plant at the Laue Longevin Institute, which is to serve the double function of detritiation and reconcentration of heavy water in the high flux reactor (HFR) is described. The process effected in this unit combines a catalytic exchange between heavy water and deuterium and a distillation of liquid deuterium. Placed in operation at the end of 1971, this installation processed heavy water from the HFR from the beginning of 1972, maintaining an isotopic concentration above 99.6 percent and a tritium activity below 2 Ci/liter. Exceptionally satisfactory performance now permits also processing of tritiated heavy water from external sources

  9. Oxidation of tritium in packed bed of noble metal catalyst for detritiation from system gases

    International Nuclear Information System (INIS)

    Nishikawa, Masabumi; Takeishi, Toshiharu; Munakata, Kenzo; Kotoh, Kenji; Enoeda, Mikio

    1985-01-01

    Catalytic oxidation rates of tritium in the bed of the noble metal catalysts are obtained and compared with the oxidation rates observed for the packed bed of spongy copper oxide or hopcalites. Use of Pt- or Pd-aluminia catalysts is recommended in this study because they give effective oxidation rates of tritium in the ambient temperature range. The adsorption performance of tritiated water in the catalyst bed is also discussed. (orig.)

  10. Computational model for real-time determination of tritium inventory in a detritiation installation

    International Nuclear Information System (INIS)

    Bornea, Anisia; Stefanescu, Ioan; Zamfirache, Marius; Stefan, Iuliana; Sofalca, Nicolae; Bidica, Nicolae

    2008-01-01

    Full text: At ICIT Rm.Valcea an experimental pilot plant was built having as main objective the development of a technology for detritiation of heavy water processed in the CANDU-type reactors of the nuclear power plant at Cernavoda, Romania. The aspects related to safeguards and safety for such a detritiation installation being of great importance, a complex computational model has been developed. The model allows real-time calculation of tritium inventory in a working installation. The applied detritiation technology is catalyzed isotopic exchange coupled with cryogenic distillation. Computational models for non-steady working conditions have been developed for each process of isotopic exchange. By coupling these processes tritium inventory can be determined in real-time. The computational model was developed based on the experience gained on the pilot installation. The model uses a set of parameters specific to isotopic exchange processes. These parameters were experimentally determined in the pilot installation. The model is included in the monitoring system and uses as input data the parameters acquired in real-time from automation system of the pilot installation. A friendly interface has been created to visualize the final results as data or graphs. (authors)

  11. Review of tritium confinement and atmosphere detritiation system in hot cells complex

    International Nuclear Information System (INIS)

    Rizzello, Claudio; Borgognoni, Fabio; Pinna, Tonio; Tosti, Silvano

    2010-01-01

    The tritium confinement strategy adopted during the past years in the ITER hot cell building is compared to the safety requirements given by the standard ISO-17873 'Nuclear facilities - criteria for the design and operation of ventilation systems for nuclear installations other than nuclear reactors'. In fact, this is the reference safety guideline recommended by French licensing authorities. Several features of the considered design of the hot cell building are not in agreement with these guidelines. Main discrepancies concern the zoning of the hot cell complex, the flow rates of ventilation, and the possibility to recycle the room atmosphere and to detritiate the effluent air. These aspects are discussed together with some proposed modifications of the design.

  12. Analysis of experimental air-detritiation data using TSOAK-M1

    International Nuclear Information System (INIS)

    Land, R.H.; Maroni, V.A.; Minkoff, M.

    1980-01-01

    A computer code (TSOAK-M1) has been developed which permits the determination of tritium reaction (T 2 to HTO)/adsorption/release and instrument correction parameters from enclosure (building) detritiation test data. The code is based on a simplified model which treats each parameter as a normalized time-independent constant throughout the data-unfolding steps. TSOAK-M1 was used to analyze existing small-cubicle test data with good success, and the resulting normalized parameters were employed to evaluate hypothetical reactor-building detritiation scenarios. It was concluded from the latter evaluation that the complications associated with moisture formation, adsorption, and release, particularly in terms of extended cleanup times, may not be as great as was previously thought. It is recommended that the validity of the TSOAK-M1 model be tested using data from detritiation tests conducted on large experimental enclosures (5 to 10 m 3 ) and, if possible, actual facility buildings

  13. A study concerning tritium concentration evolution in the moderator of a CANDU reactor connected on-line to a detritiation facility

    International Nuclear Information System (INIS)

    Bidica, Nicolae; Bornea, Anisia

    2005-01-01

    The present work is a theoretical study on the tritium concentration evolution in the CANDU reactor moderator connected on-line with a detritiation facility. This study is based on a calculation model which takes into account the evolution curve of the tritium concentration in the absence of detritiation process in both the moderator and SPTC of the Unit 1 CANDU reactor at Cernavoda NPP. This study leads to determination of the tritium concentration evolution in the moderator in the presence of the detritiation process for both a range of intake flows and initial concentration. Also, the intake flow change will be analyzed for a detritiation facility as a function of tritium initial concentration existing in the moderator in the case of a survey of the detritiation over a given period of time. The conclusions of this study were the following: - an optimum of the detritiation factor can be determined; - detritiation starts at a lower value for the tritium concentration in moderator which reduces the strain upon the detritiation facility and therefore the costs of its building, maintenance and operation. (authors)

  14. R and D of atmosphere detritiation system for ITER in JAEA

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Takumi, E-mail: hayashi.takumi@jaea.go.jp [Tritium Technol. Gr.: Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki Pref. 319-1195 (Japan); Iwai, Yasunori; Kobayashi, Kazuhiro; Nakamura, Hirofumi; Yamanishi, Toshihiko [Tritium Technol. Gr.: Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki Pref. 319-1195 (Japan); Perevezentsev, Alexander [Tritium Plant Gr.: ITER Organization, Cadarache Site (France)

    2010-12-15

    In order to establish an effective ITER atmosphere detritiation system (DS), JAEA (Japan Atomic Energy Agency) has investigated the performance and the durability of the system at various incident/accident conditions in support of finalizing the DS conceptual design through the ITER design review. The current DS as the Safety Important Component (SIC) has been discussed and mainly consists of catalytic reactors, wet scrubber columns (SCs), and blowers. The functional failure of the DS designed with SC was evaluated using a database of failure experiences of various valves, controllers, and components. Regarding the tritium release into the biggest confinement sector of the Tokamak gallery, this design is improved by more than two orders of magnitude compared to the original DS designed with molecular sieves (MSs) dryer beds in the 2001 design report. This improvement is achieved mainly by the reduction of frequency of valve operation, like MS dryers requiring periodical regeneration, and by the standardized module arrangement of the DS with SC.

  15. Light water detritiation

    Energy Technology Data Exchange (ETDEWEB)

    Fedorchenko, O.A.; Aleksee, I.A.; Bondarenko, S.D.; Vasyanina, T.V. [B.P. Konstantinov Petersburg Nuclear Physics Institute of National Research Centre ' Kurchatov Institute' , Gatchina (Russian Federation)

    2015-03-15

    Hundreds of thousands of tons of tritiated light water have been accumulating from the enterprises of nuclear fuel cycles around the world. The Dual-Temperature Water-Hydrogen (DTWH) process looks like the only practical alternative to Combined Electrolysis and Catalytic Exchange (CECE). In DTWH power-consuming lower reflux device (electrolytic cell) is replaced by a so-called 'hot tower' (LPCE column operating at conditions which ensure relatively small value of elementary separation factor α(hot)). In the upper, cold tower, the tritium transfers from hydrogen to water while in the lower, hot tower - in the opposite direction - from water to hydrogen. The DTWH process is much more complicated compared to CECE; it must be thoroughly computed and strictly controlled by an automatic control system. The use of a simulation code for DTWH is absolutely important. The simulation code EVIO-5 deals with 3 flows inside a column (hydrogen gas, water vapour and liquid water) and 2 simultaneous isotope exchange sub-processes (counter-current phase exchange and co-current catalytic exchange). EVIO-5 takes into account the strong dependence of process performance on given conditions (temperature and pressure). It calculates steady-state isotope concentration profiles considering a full set of reversible exchange reactions between different isotope modifications of water and hydrogen (12 molecular species). So the code can be used for simulation of LPCE column operation for detritiation of hydrogen and water feed, which contains H and D not only at low concentrations but above 10 at.% also. EVIO-5 code is used to model a Tritium Removal Facility with a throughput capacity of about 400 m{sup 3}/day. Simulation results show that a huge amount of wet-proofed catalyst is required (about 6000 m{sup 3}), mainly (90%) in the first stage. One reason for these large expenses (apart from a big scale of the problem itself) is the relatively high tritium separation factor in the

  16. Light water detritiation

    International Nuclear Information System (INIS)

    Fedorchenko, O.A.; Aleksee, I.A.; Bondarenko, S.D.; Vasyanina, T.V.

    2015-01-01

    Hundreds of thousands of tons of tritiated light water have been accumulating from the enterprises of nuclear fuel cycles around the world. The Dual-Temperature Water-Hydrogen (DTWH) process looks like the only practical alternative to Combined Electrolysis and Catalytic Exchange (CECE). In DTWH power-consuming lower reflux device (electrolytic cell) is replaced by a so-called 'hot tower' (LPCE column operating at conditions which ensure relatively small value of elementary separation factor α(hot)). In the upper, cold tower, the tritium transfers from hydrogen to water while in the lower, hot tower - in the opposite direction - from water to hydrogen. The DTWH process is much more complicated compared to CECE; it must be thoroughly computed and strictly controlled by an automatic control system. The use of a simulation code for DTWH is absolutely important. The simulation code EVIO-5 deals with 3 flows inside a column (hydrogen gas, water vapour and liquid water) and 2 simultaneous isotope exchange sub-processes (counter-current phase exchange and co-current catalytic exchange). EVIO-5 takes into account the strong dependence of process performance on given conditions (temperature and pressure). It calculates steady-state isotope concentration profiles considering a full set of reversible exchange reactions between different isotope modifications of water and hydrogen (12 molecular species). So the code can be used for simulation of LPCE column operation for detritiation of hydrogen and water feed, which contains H and D not only at low concentrations but above 10 at.% also. EVIO-5 code is used to model a Tritium Removal Facility with a throughput capacity of about 400 m 3 /day. Simulation results show that a huge amount of wet-proofed catalyst is required (about 6000 m 3 ), mainly (90%) in the first stage. One reason for these large expenses (apart from a big scale of the problem itself) is the relatively high tritium separation factor in the hot tower

  17. Concepts for detritiation of waste liquids

    International Nuclear Information System (INIS)

    King, C.M.; Van Brunt, V.; Garber, A.R.; King, R.B.

    1991-01-01

    Tritium is formed in thermal nuclear reactors both by neutron activation of elements such as deuterium and lithium and by ternary fission in the fuel. It is a weak beta-emitter with a short half-life, 12.3 years, and its radiological significance in reactor discharges is very low. In heavy-water-cooled and -moderated reactors, such as the SRS reactors, the tritium concentration in the moderator is sufficiently high to cause a potential hazard to operators, so research and development programs have been carried out on processes to remove the tritium. Detritiation of light water has also been the subject of major R ampersand D efforts world-wide, because reprocessing operations can generate significant quantities of tritium in liquid waste, and high concentrations of tritium may arise in some aqueous streams in future fusion reactors. This paper presents a review of some of the methods that have been proposed, studied, and developed for removal of tritium from light and heavy water, along with some new concepts for aqueous detritiation directly from liquid oxide (HTO) bearing feed streams

  18. Procedures for the characterization of the detritiation of steel, Inconel and graphite

    International Nuclear Information System (INIS)

    Poletiko, C.; Trabuc, P.; Durand, J.; Tormos, B.; Pignoly, L.

    2006-01-01

    Due to its high diffusivity and different trapping phenomena, tritium is present in materials, such as steel or Inconel that are in use in different parts of a nuclear power reactor, or even in graphite which is present in fusion reactor or in future HTR. From waste management point of view, it is necessary to know as accurately as possible the tritium inventory in such materials before disposal. Moreover the knowledge of tritium species (HTO or HT, etc) is also a significant information in case of detritiation prior to storage, since countries regulation already limit tritium contents and releases. Three different strategies for tritiated waste management are foreseen: the first one is based upon a storage with confined packages, the second one is waiting for radioactive decay while the third one consists in the application of detritiation processes. Studies have been performed to determine different processes that could be used for tritium removal. The aim of this paper was, to study, at laboratory scale, different detritiation procedures which may be used for stainless steel, Inconel and carbon materials. Thermal detritiation kinetics till 1300 K has been studied under various atmospheres; full chemical dissolution of samples has also been performed for steel, Inconel and graphite, this to perfectly know the tritium content in such matrices. A particular attention must be applied to Inconel, the main reason is linked to the presence of titanium which is supposed to be a tritium trap. Finally, a study of tritium content in steel and Inconel layers has also been made, to learn about the tritium behaviour. All results are given, allowing the possibility to take a decision either for detritiation procedure or storage conditions. The main result is that thermal out-gassing for steel and graphite enables higher than 95 % tritium extraction from the bulk at temperature in the range of 600 K, without any material destruction under hi-tech gas (Ar + 5% volume H 2 ), on

  19. Transient response simulation of gas separation membrane module for an atmosphere detritiation system

    International Nuclear Information System (INIS)

    Sugiyama, Takahiko; Tanaka, Masahiro; Munakata, Kenzo; Yamamoto, Ichiro

    2012-01-01

    Transient response of a gas separation membrane module for the atmosphere detritiation system was numerically simulated with a mass transfer model. The module contains thousands of hollow fiber type polyimide membranes. The simulation model took into account permeation of water vapor through the dense layer of the membrane, diffusive transfer through the porous support layer and adsorption/desorption of water vapor into the matrix of the porous layer. The slow responses of the water vapor concentration in the retentate and the permeation rate were well reproduced by the present simulation, and transient changes in a follow fiber membrane were investigated in detail. The inventory and the mean residence time of water vapor at 303 K were estimated for the commercial membrane module (UMS-B2, Ube industries, Ltd.) as 5.7 × 10 −3 mol and 380 s, respectively.

  20. Evaluation and mitigation of tritium memory in detritiation dryers

    International Nuclear Information System (INIS)

    Malara, C.; Ricapito, I.; Edwards, R.A.H.; Toci, F.

    1999-01-01

    In atmospheric detritiation, and other tritium processes, tritium is adsorbed on zeolites (molecular sieves) in the form of tritiated water. Regeneration removes almost all the physically adsorbed water, but a proportion remains permanently in the zeolite and binder structure as chemically bound water or hydroxyl groups. Exchange between adsorbed water and bound water means that tritiated water is retained in the structure after regeneration. At the end of its life, the zeolite therefore constitutes a tritiated waste. Furthermore, if an atmosphere detritiation dryer (ADD) gets highly contaminated from a tritium spill, retained tritium contaminates both the small amount of vapour leaving the bed during the next drying cycle, and the water produced in the subsequent regeneration. This report first describes experiments to measure the tritiated water retained in a 5A zeolite bed after standard regeneration treatments, and then investigates strategies to mitigate the effect: more thorough regeneration and isotope swamping or elution. The effect of zeolite ageing after thermal cycling is also seen. (orig.)

  1. Design of a Cryogenic Distillation Column for JET Water Detritiation System for Tritium Recovery

    International Nuclear Information System (INIS)

    Parracho, A.I.; Camp, P.; Dalgliesh, P.; Hollingsworth, A.; Lefebvre, X.; Lesnoj, S.; Sacks, R.; Shaw, R.; Smith, R.; Wakeling, B.

    2015-01-01

    A Water Detritiation System (WDS) is currently being designed and manufactured to be installed in the Active Gas Handling System (AGHS) of JET, currently the largest magnetic fusion experiment in the world. JET has been designed and built to study fusion operating conditions with the plasma fuelling done by means of a deuterium-tritium gas mixture. AGHS is a plant designed and built to safely process gas mixtures and impurities containing tritium recovered from the JET torus exhaust gases. Tritium is removed from these gas mixtures and recycled. Tritium depleted gases are sent to Exhaust Detritiation System (EDS) for final tritium removal prior to discharge into the environment. In EDS, tritium and tritiated species are catalytically oxidized into water, this tritiated water is then adsorbed onto molecular sieve beds (MSB). After saturation the MSBs are heated and the water is desorbed and collected for tritium recovery. The WDS facility is designed to recover tritium from water with an average activity of 1.9 GBq/l, and is able to process water with activities of 85 GBq/l and higher. Tritiated water is filtered and supplied to the electrolyser where the water is converted into gaseous oxygen and tritiated hydrogen. The hydrogen stream is first purified by selective diffusion through membranes of palladium alloy and then is fed to two cryogenic distillation columns (CD). These operate in parallel or in series depending on the water activity. In the CD columns, hydrogen isotopes containing tritium are recovered as the bottom product and hydrogen, the top product, is safely discarded to a stack. The CD columns are foreseen to have a throughput between 200 and 300 mole/h of hydrogen isotopes vapour and they operate at approximately ≈21.2K and 105 kPa. The design of the CD columns will be presented in this work. This work has been carried out within the framework of the Contract for the Operation of the JET Facilities and has received funding from the European Union

  2. A study on the deactivation and stability of hydrophobic catalyst for hydrogen isotope exchange

    International Nuclear Information System (INIS)

    Sohn, Soon Hwan

    2006-02-01

    The hydrophobic catalyst has been prepared by deposition of platinum on porous styrene divinylbenzene copolymers(Pt/SDBC) and at the same time a separated type catalytic reactor has been developed for the Wolsong tritium removal facility(WTRF). Several tests carried out to obtain the experimental performance data of the Pt/SDBC with a recycle reactor system. The long-term stability was also measured with the Pt/SDBC catalyst immersed in water for a long time. The long-term deactivations of the Pt/SDBC catalyst were evaluated quantitatively by mathematical models. The simple mathematical models were presented to evaluate the uniform poisoning and shell progressive poisoning to be occurred simultaneously during the hydrogen isotope exchange between hydrogen gas and liquid water in the Liquid Phase Catalytic Exchange(LPCE) column. The uniform poisoning was well characterized by a time on stream theory and then the deactivation parameters were determined from the experimental performance data. The impurity poisoning was derived by a shell progressive model with two-layer mass transfer. The water vapor condensation was a main cause of the reversible uniform poisoning for the Pt/SDBC catalyst. The values of the decay rate constant (K d ) and order of the decay reaction(m) were of 2 and 4, respectively, based on the experimental data. It indicated that the decay might be attributable to pore mouth poisoning. From the long-term stability of the catalyst immersed in water, there was no intrinsic decay of catalyst activity due to water logging to the catalyst. The activity decreased by only 7% over 18 months, which was equivalent to a catalyst half-life longer than 15 years. On the basis of the above deactivation parameters, the values for k c /k co with Thiele modulus=20 after 3 years and 10 years of operation were expected about 19% and 15% of the initial activity, respectively, while the values for k c /k co with Thiele modulus=100 were of about 22% and 18%, respectively

  3. Return on experience on the detritiation process in Valduc; Retour d'experience du procede de detritiation de Valduc

    Energy Technology Data Exchange (ETDEWEB)

    Leterq, D. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Bussiere, P. [CEA Valduc, DTMN, 21 - Is-sur-Tille (France)

    2009-07-01

    The authors recall the evolutions of the detritiation practices and processes in Valduc since the beginning of the 1970's. They also discuss the processing capacities and performance, and the results obtained in terms of evolution of quantities of released tritium. They discuss the implications of this processing for the management of waters which are trapped in the zeolite during the process. They finally evoke perspectives to reduce and possibly suppress the quantities of tritiated waters which are now produced

  4. Water detritiation processing of JET purified waste water using the TRENTA facility at Tritium Laboratory Karlsruhe

    Energy Technology Data Exchange (ETDEWEB)

    Michling, R., E-mail: robert.michling@kit.edu; Bekris, N.; Cristescu, I.; Lohr, N.; Plusczyk, C.; Welte, S.; Wendel, J.

    2013-10-15

    Highlights: • Operation of a water detritiation facility under optimized conditions for high detritiation performances. • Improvement of operational procedures to process tritiated waste water. • Handling and reduction of tritiated waste water to achieve enriched low volume tritiated water for sufficient storage. • Demonstration of the efficient availability of the TRENTA WDS facility for technical scale operation. -- Abstract: A Water Detritiation System (WDS) is required for any Fusion machine in order to process tritiated waste water, which is accumulated in various subsystems during operation and maintenance. Regarding the European procurement packages for the ITER tritium fuel cycle, the WDS test facility TRENTA applying the Combined Electrolysis Catalytic Exchange (CECE) process was developed, installed and is currently in operation at the Tritium Laboratory Karlsruhe (TLK). Besides the on-going R and D work for the design of ITER WDS, the current status of the TRENTA facility provides the option to utilize the WDS for processing tritiated water. Therefore, in the framework of the EFDA JET Fusion Technology Work Programme 2011, the TLK was able to offer the capability on a representative scale to process tritiated water, which was produced during normal operation at JET. The task should demonstrate the availability of the CECE process to handle and detritiate the water in terms of tritium enrichment and volume reduction. The operational program comprised the processing of purified tritiated water from JET, with a total volume of 180 l and an activity of 74 GBq. The paper will give an introduction to the TRENTA WDS facility and an overview of the operational procedure regarding tritiated water reduction. Data concerning required operation time, decontamination and enrichment performances and different operating procedures will be presented as well. Finally, a preliminary study on a technical implementation of processing the entire stock of JET

  5. Water detritiation processing of JET purified waste water using the TRENTA facility at Tritium Laboratory Karlsruhe

    International Nuclear Information System (INIS)

    Michling, R.; Bekris, N.; Cristescu, I.; Lohr, N.; Plusczyk, C.; Welte, S.; Wendel, J.

    2013-01-01

    Highlights: • Operation of a water detritiation facility under optimized conditions for high detritiation performances. • Improvement of operational procedures to process tritiated waste water. • Handling and reduction of tritiated waste water to achieve enriched low volume tritiated water for sufficient storage. • Demonstration of the efficient availability of the TRENTA WDS facility for technical scale operation. -- Abstract: A Water Detritiation System (WDS) is required for any Fusion machine in order to process tritiated waste water, which is accumulated in various subsystems during operation and maintenance. Regarding the European procurement packages for the ITER tritium fuel cycle, the WDS test facility TRENTA applying the Combined Electrolysis Catalytic Exchange (CECE) process was developed, installed and is currently in operation at the Tritium Laboratory Karlsruhe (TLK). Besides the on-going R and D work for the design of ITER WDS, the current status of the TRENTA facility provides the option to utilize the WDS for processing tritiated water. Therefore, in the framework of the EFDA JET Fusion Technology Work Programme 2011, the TLK was able to offer the capability on a representative scale to process tritiated water, which was produced during normal operation at JET. The task should demonstrate the availability of the CECE process to handle and detritiate the water in terms of tritium enrichment and volume reduction. The operational program comprised the processing of purified tritiated water from JET, with a total volume of 180 l and an activity of 74 GBq. The paper will give an introduction to the TRENTA WDS facility and an overview of the operational procedure regarding tritiated water reduction. Data concerning required operation time, decontamination and enrichment performances and different operating procedures will be presented as well. Finally, a preliminary study on a technical implementation of processing the entire stock of JET

  6. A practical process for light-water detritiation at large scales

    Energy Technology Data Exchange (ETDEWEB)

    Boniface, H.A. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Robinson, J., E-mail: jr@tyne-engineering.com [Tyne Engineering, Burlington, ON (Canada); Gnanapragasam, N.V.; Castillo, I.; Suppiah, S. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    AECL and Tyne Engineering have recently completed a preliminary engineering design for a modest-scale tritium removal plant for light water, intended for installation at AECL's Chalk River Laboratories (CRL). This plant design was based on the Combined Electrolysis and Catalytic Exchange (CECE) technology developed at CRL over many years and demonstrated there and elsewhere. The general features and capabilities of this design have been reported as well as the versatility of the design for separating any pair of the three hydrogen isotopes. The same CECE technology could be applied directly to very large-scale wastewater detritiation, such as the case at Fukushima Daiichi Nuclear Power Station. However, since the CECE process scales linearly with throughput, the required capital and operating costs are substantial for such large-scale applications. This paper discusses some options for reducing the costs of very large-scale detritiation. Options include: Reducing tritium removal effectiveness; Energy recovery; Improving the tolerance of impurities; Use of less expensive or more efficient equipment. A brief comparison with alternative processes is also presented. (author)

  7. Treatment of tritiated exhaust gases at the Tritium Laboratory Karlsruhe

    Energy Technology Data Exchange (ETDEWEB)

    Hutter, E.; Besserer, U. [Kernforschungszentrum Karlsruhe GmbH (Germany); Jacqmin, G. [NUKEM GmbH, Industreistr, Alzenau (Germany)

    1995-02-01

    The Tritium Laboratory Karlsruhe (TLK) accomplished commissioning; tritium involving activities will start this year. The laboratory is destined mainly to investigating processing of fusion reactor fuel and to developing analytic devices for determination of tritium and tritiated species in view of control and accountancy requirements. The area for experimental work in the laboratory is about 800 m{sup 2}. The tritium infrastructure including systems for tritium storage, transfer within the laboratory and processing by cleanup and isotope separation methods has been installed on an additional 400 m{sup 2} area. All tritium processing systems (=primary systems), either of the tritium infrastructure or of the experiments, are enclosed in secondary containments which consist of gloveboxes, each of them connected to the central depressurization system, a part integrated in the central detritiation system. The atmosphere of each glovebox is cleaned in a closed cycle by local detritiation units controlled by two tritium monitors. Additionally, the TLK is equipped with a central detritiation system in which all gases discharged from the primary systems and the secondary systems are processed. All detritiation units consist of a catalyst for oxidizing gaseous tritium or tritiated hydrocarbons to water, a heat exchanger for cooling the catalyst reactor exhaust gas to room temperature, and a molecular sieve bed for adsorbing the water. Experiments with tracer amounts of tritium have shown that decontamination factors >3000 can be achieved with the TLK detritiation units. The central detritiation system was carefully tested and adjusted under normal and abnormal operation conditions. Test results and the behavior of the tritium barrier preventing tritiated exhaust gases from escaping into the atmosphere will be reported.

  8. Preparation of alveolate hydrophobic catalyst for tritium waste gas treatment

    International Nuclear Information System (INIS)

    Yang, Yong; Peng, Shuming; Wang, Heyi; Du, Yang; Li, Jiamao

    2016-01-01

    Highlights: • The catalyst is hydrophobic, it will not be poisoned by steam in room air at room temperature which is better than Pt-Al 2 O 3 . • At room temperature, the conversion of low concentration of H2 and tritium gas in room air over the catalyst is high. • The air resistance of catalyst is much lower than graininess Pt-Al 2 O 3 . • It is inorganic and will not burn. - Abstract: To prepare a catalyst for the detritiation of waste gases at high flow rates, a heat-resistant hydrophobic zeolitic molecular sieve coating was synthesized on the surface of alveolate cordierite by hydrothermal processing. The alveolate hydrophobic catalyst prepared from the support was essentially waterproof and not easily poisoned by moisture. At room temperature, the conversion of low concentrations of H 2 in humid air over the catalyst was higher than 95% at different space velocities (0–16,000 h −1 ) and different relative humidities. The reaction rate constant of the oxidation of tritium over alveolate hydrophobic catalyst is 0.182 s −1 at 293.3 K–293.7 K and 59%–60% RH, it is much higher than the catalyst of reference honeycomb catalyst.

  9. Experimental determination of reaction rates of water. Hydrogen exchange of tritium with hydrophobic catalysts

    International Nuclear Information System (INIS)

    Bixel, J.C.; Hartzell, B.W.; Park, W.K.

    1976-01-01

    This study was undertaken to obtain data needed for further development of a process for the enrichment and removal of tritium from the water associated with light-water reactors, fuel-reprocessing plants, and tritium-handling laboratories. The approach is based on the use of antiwetting, hydrophobic catalysts which permit the chemical exchange reactions between liquid water and gaseous hydrogen in direct contact, thus eliminating problems of catalyst deactivation and the complexity of reactor design normally associated with current catalytic-detritiation techniques involving gas-phase catalysis. An apparatus and procedure were developed for measuring reaction rates of water-hydrogen chemical exchange with hydrophobic catalysts. Preliminary economic evaluations of the process were made as it might apply to the AGNS fuel reprocessing plant

  10. Performance characterization of hydrogen isotope exchange and recombination catalysts for tritium processing

    International Nuclear Information System (INIS)

    Suppiah, S.; Ryland, D.; Marcinkowska, K.; Boniface, H.; Everatt, A.

    2010-01-01

    AECL's hydrogen isotope exchange catalyst and recombination catalysts have been successfully applied to a wide range of industrial tritium-removal applications. The catalysts are used for Liquid Phase Catalytic Exchange (LPCE) and for gas-phase and trickle-bed recombination of hydrogen isotopes and have led to process simplification, improved safety and operational advantages. Catalyst performance design equations derived from laboratory testing of these catalysts have been validated against performance under industrial conditions. In a Combined Electrolysis and Catalytic Exchange (CECE) demonstration plant analyses of LPCE and recombiner efficiency were carried out as a function of catalyst activity over a wide range of operation. A steady-state process simulation used to model and design the hydrogen-water isotopic exchange processes, such as the CECE detritiation plant, was validated using the results of this demonstration. Catalyst development for isotope-exchange and recombination applications has continued over the last decade. As a result, significant improvements in catalyst performance have been achieved for these applications. This paper outlines the uniqueness of AECL's specialized catalysts and process designs for these applications with examples from laboratory and industrial case studies.

  11. TSOAK-M1: a computer code to determine tritium reaction/adsorption/release parameters from experimental results of air-detritiation tests

    International Nuclear Information System (INIS)

    Land, R.H.; Maroni, V.A.; Minkoff, M.

    1979-01-01

    A computer code has been developed which permits the determination of tritium reaction (T 2 to HTO)/adsorption/release and instrument correction parameters from enclosure (building) - detritiation test data. The code is based on a simplified model which treats each parameter as a normalized time-independent constant throughout the data-unfolding steps. Because of the complicated four-dimensional mathematical surface generated by the resulting differential equation system, occasional local-minima effects are observed, but these effects can be overcome in most instances by selecting a series of trial guesses for the initial parameter values and observing the reproducibility of final parameter values for cases where the best overall fit to experimental data is achieved. The code was then used to analyze existing small-cubicle test data with good success, and the resulting normalized parameters were employed to evaluate hypothetical reactor-building detritiation scenarios. It was concluded from the latter evaluation that the complications associated with moisture formation, adsorption, and release, particularly in terms of extended cleanup times, may not be as great as was previously thought. It is recommended that the validity of the TSOAK-M1 model be tested using data from detritiation tests conducted on large experimental enclosures (5 to 10 cm 3 ) and, if possible, actual facility buildings

  12. Preparation and performance of Pt/PTFE/Foam SiC as a hydrophobic catalyst for LPCE

    International Nuclear Information System (INIS)

    He, Jianchao; Wang, Heyi; Xiao, Chengjian; Li, Jiamao; Chen, Ping; Hou, Jingwei

    2016-01-01

    Highlights: • A new type of foam material, Foam SiC with three-dimensional network structure, was chosen as the carrier of catalyst. • Foam SiC was hydrophobic treated by PTFE, and achieved a good hydrophobic property. • Pt/PTFE/Foam SiC was prepared by impregnation method with Pt-organic solution and gaseous phase reduction method. • The hydrophobic catalysts were packed with Dixon phosphor bronze gauze rings (about 3 mm × 3 mm) in LPCE system to test the catalytic performance. • The effect of different size of the catalyst on LPCE was been tested. - Abstract: Platinum catalysts supported on a composite of polytetrafluoroethylene (PTFE) and Foam SiC (Pt/PTFE/Foam SiC) have been proposed and prepared by an impregnation method. The as-prepared Pt/PTFE/Foam SiC was characterized by compression load testing, dynamic contact angle measurement, SEM, XRD, and TEM. The results show that the catalyst prepared by triple hydrophobic treatment had an initial contact angle of 134.2°, a good compression performance of 3.2 MPa, and platinum nanoparticles of 12.1 nm (average size). The catalytic activity of the catalyst was tested with different packing methods, reaction temperatures, and gas-liquid ratios. An excellent hydrogen isotope exchange performance was observed using a hydrophilic packing material-to-catalyst ratio of 25% and reaction temperature of 80 °C. Pt/PTFE/Foam SiC may be used as a hydrophobic catalyst for a water detritiation system (WDS) via a liquid-phase catalytic exchange process (LPCE).

  13. Preparation and performance of Pt/PTFE/Foam SiC as a hydrophobic catalyst for LPCE

    Energy Technology Data Exchange (ETDEWEB)

    He, Jianchao; Wang, Heyi, E-mail: hywang@caep.cn; Xiao, Chengjian; Li, Jiamao; Chen, Ping; Hou, Jingwei

    2016-12-15

    Highlights: • A new type of foam material, Foam SiC with three-dimensional network structure, was chosen as the carrier of catalyst. • Foam SiC was hydrophobic treated by PTFE, and achieved a good hydrophobic property. • Pt/PTFE/Foam SiC was prepared by impregnation method with Pt-organic solution and gaseous phase reduction method. • The hydrophobic catalysts were packed with Dixon phosphor bronze gauze rings (about 3 mm × 3 mm) in LPCE system to test the catalytic performance. • The effect of different size of the catalyst on LPCE was been tested. - Abstract: Platinum catalysts supported on a composite of polytetrafluoroethylene (PTFE) and Foam SiC (Pt/PTFE/Foam SiC) have been proposed and prepared by an impregnation method. The as-prepared Pt/PTFE/Foam SiC was characterized by compression load testing, dynamic contact angle measurement, SEM, XRD, and TEM. The results show that the catalyst prepared by triple hydrophobic treatment had an initial contact angle of 134.2°, a good compression performance of 3.2 MPa, and platinum nanoparticles of 12.1 nm (average size). The catalytic activity of the catalyst was tested with different packing methods, reaction temperatures, and gas-liquid ratios. An excellent hydrogen isotope exchange performance was observed using a hydrophilic packing material-to-catalyst ratio of 25% and reaction temperature of 80 °C. Pt/PTFE/Foam SiC may be used as a hydrophobic catalyst for a water detritiation system (WDS) via a liquid-phase catalytic exchange process (LPCE).

  14. Tritium isotopic exchange in air detritiation dryers

    International Nuclear Information System (INIS)

    Everatt, A.E.; Johnson, R.E.; Senohrabek, J.A.; Shultz, C.M.

    1989-02-01

    Isotopic exchange between tritiated and non-tritiated water species in a molecular sieve bed has been demonstrated. At high humidities (+6 degrees Celsius dew point) the rate of tritium isotopic exchange in a 2.4 L molecular sieve bed has been demonstrated to be at least 50% of published exchange rates. In an industrial-sized air detritiation dryer, utilizing the pretreatment technique of H 2 O steam washing to elute the residual tritium, a DF of 12 600 has been demonstrated when operating at an inlet vapor tritium concentration of 14 Ci/kg and at inlet and outlet dew points of 4.8 and -54 degrees Celsius, respectively. In the NPD dryer bed studied, which was not optimally designed for full benefit from isotopic exchange, at least one order of magnitude in additional detritiation is attributed to isotopic exchange in the unsaturated zone. The technique of eluting the residual tritium from an industrial sized bed by H 2 O washing at high temperature, high humidity and low bed loading has been demonstrated to be a fast and effective way of removing tritium from a molecular sieve bed during regeneration. The isotopic exchange model accurately predicted the exchange between tritiated and non-tritiated water species in a molecular sieve bed where there is no net adsorption or desorption. The model's prediction of the tritium breakthrough trend observed in the NPD tests was poor; however, a forced fit can be achieved if the exchange rates in the MTZ and the unsaturated zone are manipulated. More experiments are needed to determine the relative rates of tritium exchange in the saturated, mass transfer, and unsaturated zones of a dryer bed

  15. Return on experience on the detritiation process in Valduc

    International Nuclear Information System (INIS)

    Leterq, D.; Bussiere, P.

    2009-01-01

    The authors recall the evolutions of the detritiation practices and processes in Valduc since the beginning of the 1970's. They also discuss the processing capacities and performance, and the results obtained in terms of evolution of quantities of released tritium. They discuss the implications of this processing for the management of waters which are trapped in the zeolite during the process. They finally evoke perspectives to reduce and possibly suppress the quantities of tritiated waters which are now produced

  16. Accounting strategy of tritium inventory in the heavy water detritiation pilot plant from ICIT Rm. Valcea

    International Nuclear Information System (INIS)

    Bidica, N.; Stefanescu, I.; Cristescu, I.; Bornea, A.; Zamfirache, M.; Lazar, A.; Vasut, F.; Pearsica, C.; Stefan, I.; Prisecaru, I.; Sindilar, G.

    2008-01-01

    In this paper we present a methodology for determination of tritium inventory in a tritium removal facility. The method proposed is based on the developing of computing models for accountancy of the mobile tritium inventory in the separation processes, of the stored tritium and of the trapped tritium inventory in the structure of the process system components. The configuration of the detritiation process is a combination of isotope catalytic exchange between water and hydrogen (LPCE) and the cryogenic distillation of hydrogen isotopes (CD). The computing model for tritium inventory in the LPCE process and the CD process will be developed basing on mass transfer coefficients in catalytic isotope exchange reactions and in dual-phase system (liquid-vapour) of hydrogen isotopes distillation process. Accounting of tritium inventory stored in metallic hydride will be based on in-bed calorimetry. Estimation of the trapped tritium inventory can be made by subtraction of the mobile and stored tritium inventories from the global tritium inventory of the plant area. Determinations of the global tritium inventory of the plant area will be made on a regular basis by measuring any tritium quantity entering or leaving the plant area. This methodology is intended to be applied to the Heavy Water Detritiation Pilot Plant from ICIT Rm. Valcea (Romania) and to the Cernavoda Tritium Removal Facility (which will be built in the next 5-7 years). (authors)

  17. Tritium emissions from a detritiation facility

    International Nuclear Information System (INIS)

    Rodrigo, L.; El-Behairy, O.; Boniface, H.; Hotrum, C.; McCrimmon, K.

    2010-01-01

    Tritium is produced in heavy-water reactors through neutron capture by the deuterium atom. Annual production of tritium in a CANDU reactor is typically 52-74 TBq/MW(e). Some CANDU reactor operators have implemented detritiation technology to reduce both tritium emissions and dose to workers and the public from reactor operations. However, tritium removal facilities also have the potential to emit both elemental tritium and tritiated water vapor during operation. Authorized releases to the environment, in Canada, are governed by Derived Release Limits (DRLs). DRLs represent an estimate of a release that could result in a dose of 1 mSv to an exposed member of the public. For the Darlington Nuclear Generating Station, the DRLs for airborne elemental tritium and tritiated water emissions are ~15.6 PBq/week and ~825 TBq/week respectively. The actual tritium emissions from Darlington Tritium Removal Facility (DTRF) are below 0.1% of the DRL for elemental tritium and below 0.2% of the DRL for tritiated water vapor. As part of an ongoing effort to further reduce tritium emissions from the DTRF, we have undertaken a review and assessment of the systems design, operating performance, and tritium control methods in effect at the DTRF on tritium emissions. This paper discusses the results of this study. (author)

  18. An overview of SCK-CEN's technological research for the treatment of tritiated waste

    International Nuclear Information System (INIS)

    Braet, J.; Bruggeman, A.; Vanderbiesen, S.

    2004-01-01

    The production of fusion energy involves the use of huge amounts of tritium, of the order of 4 x 10 19 Bq/Gwe.a. Therefore operation and dismantling of test installations and future commercial fusion reactors are not possible without the production of tritiated waste. Various categories of tritiated waste are and will be produced which require different detritiation techniques to lower the initial tritium content in the samples and to allow final waste disposal of the partly detritiated material and of all by-products generated in the processes. The current internationally adopted strategy is to convert all kinds of tritiated waste into tritiated water, which can then be treated in one water detritiation installation. Since several years SCK-CEN has been developing techniques for the treatment of tritiated waste. Amongst them technologies for the treatment of tritiated organic liquids, surface contaminated metals, contaminated concrete and most importantly water detritiation. The so-called liquid phase catalytic exchange for water detritiation requires an efficient catalyst that should furthermore be hydrophobic because of the low solubility and hence slow diffusion of hydrogen in the water layer that covers normal catalysts. In the past SCK-CEN invented and developed such a catalyst which has recently been optimized and tested in a bench scale installation. To confirm the performances of our improved catalyst for a longer period of time and in a longer column, we are now doing tests in a 2 meter high trickle bed reactor and the endurance of the catalyst is being tested at ICSI. Using a good performing catalyst, LPCE will be, in combination with electrolysis, a technically and economically sound technology for water detritiation. Other R and D focuses on the development of a system do decontaminate surface contaminated metals and concrete using superheated steam. The resulting water can in its turn be treated in a water detritiation installation. For the purpose of

  19. Cost effectiveness of detritiating water with resin columns

    International Nuclear Information System (INIS)

    Drake, R.H.; Williams, D.S.

    1997-10-01

    There are technologies in use for cleaning up concentrated tritiated process water. These are not cost effective for tritiated water with low concentrations of tritium. There are currently no cost-effective technologies for cleaning up low-tritium-concentration tritiated water, such as most tritiated groundwater, spent fuel storage basin water, or underground storage tank water. Resin removal of tritium from tritiated water at low concentrations (near the order of magnitude of drinking water standard maximums) is being tested on TA-SO (Los Alamos National Laboratory's Liquid Radioactive Waste Treatment Facility) waste streams. There are good theoretical and test indications that this may be a technologically effective means of removing tritium from tritiated water. Because of likely engineering design similarity, it is reasonable to anticipate that a resin column system's costs will be similar to some common commercial water treatment systems. Thus, the potential cost effectiveness of a resin treatment system offers hope for treating tritiated water at affordable costs. The TA-50 resin treatment cost projection of $18 per 1,000 gallons is within the same order of magnitude as cost data for typical commercial groundwater cleanup projects. The prospective Los Alamos National Laboratory (LANL) resin treatment system at $18 per 1,000 gallons appears to have a likely cost advantage of at least an order of magnitude over the competing, developmental, water detritiation technologies

  20. Endurance testing of a WDS catalyst

    International Nuclear Information System (INIS)

    Vladu, Mihaela; Brad, Sebastian; Vijulie, Mihai; Vasut, Felicia; Constantin, Marin

    2007-01-01

    Full text: The Water Detritiation System (WDS) of ITER is a safety related component since it is the final barrier against tritium discharge into the environment. Therefore, its subcomponents have to be qualified and predictions on the time evolution of performances have to be made. During the activities devoted to JET WDS, test at lower concentrations of tritium and at small scale have been performed. The goal of this work is to extend the endurance testings and to check early results by tests under relevant conditions. The degradation of the WDS catalyst can strongly affect its separation performances and consequently it will entail a raise of the tritium releases into the environment. If a catalyst based on Teflon material is used for the LPCE column of WDS, the fluoride that may be formed and released due to the tritium presence causes the corrosion of the LPCE column with unpredictable effects. Therefore the quantification of catalyst degradation and the amount of fluoride released is needed for planning the maintenance activities and to predict the operation life time of the WDS components. The manufacturing of hydrophobic catalysts with activity that is not lowered by liquid water determined the rise of interest for the isotopes separation techniques in the hydrogen - water system. The active component of these catalysts is Pt (the only material to be further discussed) that enhances the exchange between the hydrogen and water vapors. The hydrophobic support does not allow the wetting and blocking by water of the active surface. Hydrophobic catalysts were manufactured by two methods: - direct deposition of Pt into the pores of a hydrophobic support (Teflon, carbon monofluoride, poly styrene, styrene di-vinyl benzene, etc.); - deposition on a hydrophilic support, most common charcoal, followed by hydrophobization by silicon oil or by homogenizing with hydrophobic polymer (Teflon, silicon resins). This type of catalysts is one of the most studied groups due to

  1. Evaluation of AECL catalysts for hydrogen fuel-cell applications. Paper no. IGEC-1-073

    International Nuclear Information System (INIS)

    Li, J.; Suppiah, S.; Li, H.; Kutchcoskie, K.J.; Strikwerda, S.

    2005-01-01

    AECL has been engaged in the promotion of the nuclear-hydrogen economy, which envisions that hydrogen fuel cells will generate power using hydrogen as fuel produced by nuclear energy. Since AECL's catalysts developed for the production, upgrading and detritiation of heavy water are very similar to commercial fuel-cell catalysts, a program was initiated to evaluate AECL catalysts for fuel-cell applications. As a first step in this effort, a half-cell test facility was set up to characterize the performance of catalysts for hydrogen fuel cells. This paper outlines the results obtained from cathodic reduction of oxygen in a 0.5 M sulphuric acid solution on a rotating disc electrode at 65 o C. The performance of the catalysts was characterized using standard electrochemical methods including cyclic voltammetry, Voltammogram/Tafel plots and short-term stability plots. Several monometallic Pt and Pt-based bimetallic catalysts were tested and compared with a commercially available catalyst for fuel-cell applications. AECL's monometallic Pt catalysts showed comparable or better activities than commercial catalysts with similar Pt loading. An AECL Pt-based bimetallic catalyst has shown superior performance to a monometallic Pt catalyst with similar Pt loading. Evaluation of various catalyst formulations is ongoing on the half-cell facility at AECL. Further investigation of promising catalysts identified from half-cell test is also being carried out in single fuel cell on test stations under normal fuel-cell operating conditions. (author)

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

    Science.gov (United States)

    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.

  3. A methodology for determination of tritium inventory to the heavy water detritiation pilot plant from ICIT Rm. Valcea

    International Nuclear Information System (INIS)

    Bidica, N.; Stefanescu, I.; Bornea, A.; Zamfirache, M.; Lazar, A.; Vasut, F.; Pearsica, C.; Stefan, I.; Cristescu, I.; Prisecaru, I.; Sindilar, G.

    2007-01-01

    Full text: In this paper we present a methodology for determination of tritium inventory in a tritium removal facility. The method proposed is based on the developing of computing models for accountancy of the mobile tritium inventory in the separation processes of the stored tritium and of the trapped tritium inventory in the structure of the process system components. The configuration of the detritiation process is a combination of isotope catalytic exchange between water and hydrogen (LPCE) and the cryogenic distillation of hydrogen isotopes (CD). The computing model for tritium inventory in the LPCE process and the CD process will be developed based on mass transfer coefficients in catalytic isotope exchange reactions and in dual-phase system (liquid-vapour) of hydrogen isotopes distillation process. Accounting of tritium inventory stored in metallic hydride will be based on in-bed calorimetry. Estimation of the trapped tritium inventory can be made by subtraction of the mobile and stored tritium inventories from the global tritium inventory of the plant area. Determinations of the global tritium inventory of the plant area will be made on a regular basis by measuring any tritium amount entering or leaving the plant area. This methodology is intended to be applied to the Heavy Water Detritiation Pilot Plant from ICIT Rm. Valcea (Romania) and at the Cernavoda Tritium Removal Facility (which will be built in the next 5-7 years). (authors)

  4. Applications of hydrophobic Pt catalysts in separation of tritium from liquid effluents

    International Nuclear Information System (INIS)

    Ionita, Gheorghe; Popescu, Irina; Stefanescu, Ioan; Varlam, Carmen

    2003-01-01

    Hydrophobic Pt catalysts were first prepared and used in deuterium or tritium separation while after their application was extended to chemical reactions occurring in liquid water or saturated humidity environments. Capillary condensing produced at the contact with liquid water or vapors engenders in classical hydrophilic catalysts a decrease in activity what makes them inefficient. Consequently, liquid water 'repealing' catalysts are to be used allowing, at the same time gaseous reactants and reaction products to diffuse to and fro the catalytic active centers. These catalysts were successfully applied in deuterium enrichment and tritium separation based on hydrogen- liquid water isotopic exchange at both pilot and industrial scale. High activity and a prolonged stability were demonstrated and checked in: - detritiation of the heavy water used as both moderator and coolant in CANDU type reactors; removing of tritium from light water recirculated in nuclear fuel reprocessing facilities; removal and recovery of tritium from atmosphere and tritium processing installations. Due to their incontestable advantages the use of these catalysts was recently extended to other chemical processes occurring in the presence of liquid water or in high humidity environment or else when water occurs as a reaction product, such as catalytic hydrogen - oxygen recombination at room temperature or removal of stable organic pollutants from waste waters

  5. Results of experimental study on detritiation of atmosphere in large space

    International Nuclear Information System (INIS)

    Kobayashi, Kazuhiro; Hayashi, Takumi; Iwai, Yasunori; Nishi, Masataka

    2001-01-01

    In order to obtain data on tritium removal from the atmosphere of a room, which is needed for designing a reliable effective atmosphere detritiation system in a fusion reactor and for detailed analysis on its safety, intentional tritium release experiments have been carried out in a controlled space called Caisson under various atmosphere conditions at the Tritium Process Laboratory (TPL) in Japan Atomic Energy Research Institute (JAERI). In case there is no tritiated water vapor in the released tritium gas, tritium was ideally removed by constant ventilation in spite of atmospheric conditions and residence time. On the other hand, when tritiated water vapor existed in the released tritium, residual contamination on the wall of the Caisson was detected and it was found that it depended on the initial humidity in the Caisson. This tritium removal behavior was successfully analyzed by considering the adsorption and desorption reaction rates of tritiated water on the wall by the constant ventilation

  6. Process of activation of a palladium catalyst system

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    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.

  7. Catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    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.

  8. Multi-stage catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    2009-02-10

    Catalyst systems and methods provide benefits in reducing the content of nitrogen oxides in a gaseous stream containing nitric oxide (NO), hydrocarbons, carbon monoxide (CO), and oxygen (O.sub.2). The catalyst system comprises an oxidation catalyst comprising a first metal supported on a first inorganic oxide for catalyzing the oxidation of NO to nitrogen dioxide (NO.sub.2), and a reduction catalyst comprising a second metal supported on a second inorganic oxide for catalyzing the reduction of NO.sub.2 to nitrogen (N.sub.2).

  9. Optimization of catalyst system reaps economic benefits

    International Nuclear Information System (INIS)

    Le Roy, C.F.; Hanshaw, M.J.; Fischer, S.M.; Malik, T.; Kooiman, R.R.

    1991-01-01

    Champlin Refining and Chemicals Inc. is learning to optimize its catalyst systems for hydrotreating Venezuelan gas oils through a program of research, pilot plant testing, and commercial unit operation. The economic results of this project have been evaluated, and the benefits are most evident in improvements in product yields and qualities. The project has involved six commercial test runs, to date (Runs 10-15), with a seventh run planned. A summary of the different types of catalyst systems used in the test runs, and the catalyst philosophy that developed is given. Runs 10 and 11 used standard CoMo and NiMo catalysts for heavy gas oils hydrotreating. These catalysts had small pore sizes and suffered high deactivation rates because of metals contamination. When it was discovered that metals contamination was a problem, catalyst options were reviewed

  10. Hydrophobic catalyst applications in the nuclear field and in environmental studies

    International Nuclear Information System (INIS)

    Ionita, Gheorghe; Popescu, Irina; Stefanescu, Ioan; Varlam, Carmen

    2002-01-01

    The paper presents methods of preparation and applications of hydrophobic platinum catalysts in nuclear field and environmental protection. These catalysts allow the transport of gaseous reactants and reaction products to and from catalytic active centers since the pore blocking by water is avoided. Hence the activity and stability of the catalysts increase and isotopic exchange columns with simpler internal structure can be achieved. The aim of the paper is: 1. to give a data base regarding the preparation methods of the optimal catalyst type; 2. to indicate the utilization and operation procedures of hydrophobic catalysts with mixed and simple packings; 3. to evaluate the performances and applications of hydrophobic catalysts. Over one hundred of hydrophobic catalysts of the active metal/support type were prepared in our laboratory. Hydrophobic features were obtained by different methods like these: - coating a hydrophilic conventional catalyst with a hydrophobic agent such as silicone or teflon; - supporting the active metal directly into the pores of a hydrophobic support; - mixing the teflon powder with a hydrophilic conventional catalyst; coating the support with teflon followed by the impregnation with the precursor of the active metal. The most important application of these catalysts is detritiation of the heavy water used as moderator and coolant in CANDU type reactors. Build-up of tritium in heavy water following the neutron capture by deuterium leads to a reduction in the moderating properties and at the same time leads to a contamination hazard for both operation personnel and environment. Tritium recovery leads this way to both improving the moderating qualities of the heavy water and obtaining valuable pure tritium of high importance in fusion research and other laboratory studies. One gram of tritium costs about USD 10,000. The physical chemical process is water-hydrogen catalyzed isotopic exchange. Also discussed in the paper is the separation of

  11. Recycle attuned catalytic exchange (RACE) for reliable and low inventory processing of highly tritiated water

    International Nuclear Information System (INIS)

    Iseli, M.; Schaub, M.; Ulrich, D.

    1992-01-01

    The detritiation of highly tritiated water by liquid phase catalytic exchange needs dilution of the feed with water to tritium concentrations suitable for catalyst and safety rules and to assure flow rates large enough for wetting the catalyst. Dilution by recycling detritiated water from within the exchange process has three advantages: the amount and concentration of the water for dilution is controlled within the exchange process, there is no additional water load to processes located downstream RACE, and the ratio of gas to liquid flow rates in the exchange column could be adjusted by using several recycles differing in amount and concentration to avoid an excessively large number of theoretical separation stages. In this paper, the flexibility of the recycle attuned catalytic exchange (RACE) and its effect on the cryogenic distillation are demonstrated for the detritiation of the highly tritiated water from a tritium breeding blanket

  12. Status and practicality of detritiation and tritium production strategies for environmental remediation

    International Nuclear Information System (INIS)

    Fulbright, H.H.; Schwirian-Spann, A.L.; Brunt, V. van; Jerome, K.M.; Looney, B.B.

    1996-01-01

    Operation of nuclear facilities throughout the world generates wastewater, groundwater and surface water contaminated with tritium. Because of a commitment to minimize radiation exposures to ''levels as low as reasonably achievable'', the US Department of Energy supports development of tritium isotope separation technologies. Also, DOE periodically documents the status and potential viability of alternative tritium treatment technologies and management strategies. The specific objectives of the current effort are to evaluate practical engineering issues, technology acceptability issues, and costs for realistic tritium treatment scenarios. A unique feature of the assessment is that the portfolio of options was expanded to include various management strategies rather than only evaluating detritiation technologies. The ultimate purpose of this effort is to assist Environmental Restoration and its support organizations in allocating future investments

  13. Commissioning of Water Detritiation and Cryogenic Distillation Systems at TLK in View of ITER Design

    International Nuclear Information System (INIS)

    Cristescu, I.; Doerr, L.; Glugla, M.; Hellriegel, G.; Schaefer, P.; Welte, St.; Wurster, W.; Murdoch, D.

    2006-01-01

    The Water Detritiation System (WDS) of ITER is one of the key systems to control the tritium content in the effluents streams, to recover as much tritium as possible and consequently to minimize the impact on the environment. In order to mitigate the concern over tritium release into the environment during pulsed operation of the Torus, the WDS and Isotope Separation System (ISS) will operate in such way that WDS will be a final barrier for the processed protium waste gas stream discharged from ISS. The ITER ISS consists of a cascade of four cryogenic distillation columns with the aim to process mainly two gas streams, one from Torus exhaust and other from WDS mixed with the returned stream from Neutral Beam Injectors (NBI). The behavior of the CD cascade has to be characterized with high accuracy with respect to thermal and isotopic fluctuations during Torus pulses. To support the research activities needed to characterize the performances of various components for WDS and ISS processes in various working conditions and configurations as needed for ITER design, an experimental facility called TRENTA based on the combination Combined Electrolysis Catalytic Exchange (CECE) - Cryogenic Distillation (CD), representative of the ITER WDS and ISS protium separation column, is under full commissioning at TLK. The CECE process consists of a solid polymer electrolyser unit as envisaged to be used in ITER WDS, and an 8 m Liquid Phase Catalytic Exchange Column (LPCE). The Electrolysis unit was commissioned with tritiated water and the enrichment factor was measured. The experimental program on the Cryogenic distillation facility at TLK is conducted to provide the necessary design and operation information for ITER ISS. It is focused on two major issues: - To investigate the separation performances and liquid hold up of different packings in cryogenic distillation process and to validate the steady-state mathematical modeling of the process. - To investigate the CD process

  14. Sol-gel based oxidation catalyst and coating system using same

    Science.gov (United States)

    Watkins, Anthony N. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Patry, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor)

    2010-01-01

    An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

  15. Automotive catalyst strategies for future emission systems

    International Nuclear Information System (INIS)

    Williamson, W.B.; Summers, J.C.; Scaparo, J.A.

    1992-01-01

    This paper reports that while significant advances in Pt/Rh three-way catalyst (TWC) formulations have been accomplished, the use of Pd-containing catalysts for three-way emission control are of interest for overall noble metal cost reduction, lower Rh usage, and potential durability improvements. Applications of Pd are demonstrated for replacement of Pt in conventional Pt/Rh TWC systems, for use in Pd-only three-way catalysts and for lowering methanol and formaldehyde emissions at close-coupled locations on a methanol-fueled vehicle. The individual contributions of Pt, Pd and Rh for aged three-way performance indicate significant advantages of using Pd over Pt. A comparison of vehicle system control strategies illustrates that higher system temperatures significantly lower HC emissions, while air/fuel control strategies are most critical in lowering NO x emissions

  16. Status and practicality of detritiation and tritium production strategies for environmental remediation

    Energy Technology Data Exchange (ETDEWEB)

    Fulbright, H.H.; Schwirian-Spann, A.L.; Brunt, V. van [Univ. of South Carolina, Columbia, SC (US); Jerome, K.M.; Looney, B.B. [Westinghouse Savannah River Co., Aiken, SC (US)

    1996-02-26

    Operation of nuclear facilities throughout the world generates wastewater, groundwater and surface water contaminated with tritium. Because of a commitment to minimize radiation exposures to ''levels as low as reasonably achievable'', the US Department of Energy supports development of tritium isotope separation technologies. Also, DOE periodically documents the status and potential viability of alternative tritium treatment technologies and management strategies. The specific objectives of the current effort are to evaluate practical engineering issues, technology acceptability issues, and costs for realistic tritium treatment scenarios. A unique feature of the assessment is that the portfolio of options was expanded to include various management strategies rather than only evaluating detritiation technologies. The ultimate purpose of this effort is to assist Environmental Restoration and its support organizations in allocating future investments.

  17. 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.

  18. Palladium catalyst system comprising zwitterion and/or acid-functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3......COCHCOCH3), Pd (CF3COO)2, Pd(PPh3)4 or Pd2(dibenzylideneacetone)3. Such catalyst systems can be used for e.g. alkoxycarbonylation reactions, carboxylation reactions, and/or in a co-polymerization reaction, e.g. in the production of methyl propionate and/or propanoic acid, optionally in processes forming...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

  19. Methods of producing epoxides from alkenes using a two-component catalyst system

    Science.gov (United States)

    Kung, Mayfair C.; Kung, Harold H.; Jiang, Jian

    2013-07-09

    Methods for the epoxidation of alkenes are provided. The methods include the steps of exposing the alkene to a two-component catalyst system in an aqueous solution in the presence of carbon monoxide and molecular oxygen under conditions in which the alkene is epoxidized. The two-component catalyst system comprises a first catalyst that generates peroxides or peroxy intermediates during oxidation of CO with molecular oxygen and a second catalyst that catalyzes the epoxidation of the alkene using the peroxides or peroxy intermediates. A catalyst system composed of particles of suspended gold and titanium silicalite is one example of a suitable two-component catalyst system.

  20. Overview of tritium systems for the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Bartlit, J.R.; Gruetzmacher, K.M.; Fleming, R.B.

    1987-01-01

    The Compact Ignition Tokamak (CIT) is being designed at several laboratories to produce and study fully ignited plasma discharges. The tritium systems which will be needed for CIT include fueling systems and radiation monitoring and safety systems. Design of the tritium systems is the responsibility of the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. Major new tritium systems for CIT include a pellet injector, an air detritiation system and a glovebox atmosphere detritiation system. The pellet injector is being developed at Oak Ridge National Laboratory. 7 refs., 2 figs

  1. Simulation of large scale air detritiation operations by computer modeling and bench-scale experimentation

    International Nuclear Information System (INIS)

    Clemmer, R.G.; Land, R.H.; Maroni, V.A.; Mintz, J.M.

    1978-01-01

    Although some experience has been gained in the design and construction of 0.5 to 5 m 3 /s air-detritiation systems, little information is available on the performance of these systems under realistic conditions. Recently completed studies at ANL have attempted to provide some perspective on this subject. A time-dependent computer model was developed to study the effects of various reaction and soaking mechanisms that could occur in a typically-sized fusion reactor building (approximately 10 5 m 3 ) following a range of tritium releases (2 to 200 g). In parallel with the computer study, a small (approximately 50 liter) test chamber was set up to investigate cleanup characteristics under conditions which could also be simulated with the computer code. Whereas results of computer analyses indicated that only approximately 10 -3 percent of the tritium released to an ambient enclosure should be converted to tritiated water, the bench-scale experiments gave evidence of conversions to water greater than 1%. Furthermore, although the amounts (both calculated and observed) of soaked-in tritium are usually only a very small fraction of the total tritium release, the soaked tritium is significant, in that its continuous return to the enclosure extends the cleanup time beyond the predicted value in the absence of any soaking mechanisms

  2. Palladium catalyst system comprising zwitterion and/or acid-​functionalized ionic liquid

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3...... methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications....

  3. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    Morse, Jeffrey D [Martinez, CA; Sopchak, David A [Livermore, CA; Upadhye, Ravindra S [Pleasanton, CA; Reynolds, John G [San Ramon, CA; Satcher, Joseph H [Patterson, CA; Gash, Alex E [Brentwood, CA

    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.

  4. ITER hydrogen isotope separation system conceptual design description

    International Nuclear Information System (INIS)

    Busigin, A.; Sood, S.K.; Kveton, O.K.; Dinner, P.J.; Murdoch, D.K.; Leger, D.

    1990-01-01

    This paper presents integrated hydrogen Isotope Separation System (ISS) designs for ITER based on requirements for plasma exhaust processing, neutral beam injection deuterium cleanup, pellet injector propellant detritiation, waste water detritiation, and breeding blanket detritiation. Specific ISS designs are developed for a machine with an aqueous lithium salt blanket (ALSB) and a machine with a solid ceramic breeding blanket (SBB). The differences in the ISS designs arising from the different blanket concepts are highlighted. It is found that the ISS designs for the two blanket concepts considered are very similar with the only major difference being the requirement for an additional large water distillation column for ALSB water detritiation. The extraction of tritium from the ALSB is based on flash evaporation to separate the blanket water from the dissolved Li salt, with the tritiated water then being fed to the ISS for detritiation. This technology is considered to be relatively well understood in comparison to front-end processes for SBB detritiation. In the design of the cryogenic distillation portion of the ISS, it was found that the tritium inventory could be very large (> 600 g) unless specific design measures were taken to reduce it. In the designs which are presented, the tritium inventory has been reduced to about 180 g, which is less than the ITER single-failure release limit of 200 g. Further design optimization and isolation of components is expected to reduce the inventory further. (orig.)

  5. Setup and commissioning of a combined water detritiation and isotope separation experiment at the Tritium Laboratory Karlsruhe

    Energy Technology Data Exchange (ETDEWEB)

    Welte, S., E-mail: stefan.welte@kit.edu; Cristescu, I.; Dittrich, H.; Lohr, N.; Melzer, C.; Michling, R.; Plusczyk, C.; Schaefer, P.

    2013-10-15

    Highlights: • Technical scale, tritium compatible liquid phase catalytic exchange (LPCE). • Technical scale, tritium compatible cryogenic distillation. • Combines processing option for tritiated water and isotope separation. -- Abstract: The European union in kind supply for the ITER fuel cycle development consists, among others, of the water detritiation system (WDS) and the isotope separation system (ISS). In order to mitigate the release of tritium to the environment, these systems are combined by feeding hydrogen exhaust from the ISS into the WDS for final processing. Therefore, the WDS is the final tritium barrier before releasing hydrogen (H{sub 2}) exhaust to the environment. The TRENTA 4 scaled prototype facility at TLK is based on combination of the combined electrolysis and catalytic exchange (CECE) process and a cryogenic distillation (CD) process. All components are fully tritium compatible and controlled using a state of the art control system for process automation, backed up by an additional dedicated safety system. The paper will give a detailed overview of the current experimental facility including all process components. Furthermore the paper will present the results of the functional test of the WDS/ISS combination using protium and deuterium, as well the results of the first commissioning runs using HTO of approximately 5 × 10{sup 9} Bq kg{sup −1} activity concentration.

  6. Catalysts, systems and methods to reduce NOX in an exhaust gas stream

    Science.gov (United States)

    Castellano, Christopher R.; Moini, Ahmad; Koermer, Gerald S.; Furbeck, Howard

    2010-07-20

    Catalysts, systems and methods are described to reduce NO.sub.x emissions of an internal combustion engine. In one embodiment, an emissions treatment system for an exhaust stream is provided having an SCR catalyst comprising silver tungstate on an alumina support. The emissions treatment system may be used for the treatment of exhaust streams from diesel engines and lean burn gasoline engines. An emissions treatment system may further comprise an injection device operative to dispense a hydrocarbon reducing agent upstream of the catalyst.

  7. CATALYSTS NHI Thermochemical Systems FY 2009 Year-End Report

    International Nuclear Information System (INIS)

    Ginosar, Daniel M.

    2009-01-01

    Fiscal Year 2009 work in the Catalysts project focused on advanced catalysts for the decomposition of sulfuric acid, a reaction common to both the Sulfur-Iodine (S-I) cycle and the Hybrid Sulfur cycle. Prior years effort in this project has found that although platinum supported on titanium oxide will be an acceptable catalyst for sulfuric acid decomposition in the integrated laboratory scale (ILS) project, the material has short comings, including significant cost and high deactivation rates due to sintering and platinum evaporation. For pilot and larger scale systems, the catalyst stability needs to be improved significantly. In Fiscal Year 2008 it was found that at atmospheric pressure, deactivation rates of a 1 wt% platinum catalyst could be reduced by 300% by adding either 0.3 wt% iridium (Ir) or 0.3 wt% ruthenium (Ru) to the catalyst. In Fiscal Year 2009, work focused on examining the platinum group metal catalysts activity and stability at elevated pressures. In addition, simple and complex metal oxides are known to catalyze the sulfuric acid decomposition reaction. These metal oxides could offer activities comparable to platinum but at significantly reduced cost. Thus a second focus for Fiscal Year 2009 was to explore metal oxide catalysts for the sulfuric acid decomposition reaction. In Fiscal Year 2007 several commercial activated carbons had been identified for the HI decomposition reaction; a reaction specific to the S-I cycle. Those materials should be acceptable for the pilot scale project. The activated carbon catalysts have some disadvantages including low activity at the lower range of reactor operating temperature (350 to 400 C) and a propensity to generate carbon monoxide in the presence of water that could contaminate the hydrogen product, but due to limited funding, this area had low priority in Fiscal Year 2009. Fiscal Year 2009 catalyst work included five tasks: development, and testing of stabilized platinum based H2SO4 catalysts

  8. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF MOBILE SOURCE EMISSIONS CONTROL DEVICES/CLEAN DIESEL TECHNOLOGIES FUEL BORNE CATALYST WITH CLEANAIR SYSTEM'S DIESEL OXIDATION CATALYST

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the Fuel-Borne Catalyst with CleanAir System's Diesel Oxidation Catalyst manufactured by Clean Diesel Technologies, Inc. The technology is a fuel-borne catalyst used in ultra low sulfur d...

  9. Experimental Tritium Cleanup System availability analysis from 1984 to 1992

    International Nuclear Information System (INIS)

    Cadwallader, L.C.; Taylor, G.L.

    1993-05-01

    This report gives the availability percentage of the Experimental Tritium Cleanup System (ETC) at the Tritium Systems Test Assembly (TSTA), which is a fusion research and technology facility at the Los Alamos National Laboratory. The component failure reports, the numbers of components, and operating times or demands are all given in this report. Sample calculations of the failure rates obtained from these data are given in the appendices. While future fusion experiments might use different or more advanced means to detritiate room air, the analysis of this system gives a data point for an actual detritiation system. Such a data point can be extrapolated for comparison with fault tree results on system designs, or can be used in a Bayesian failure rate analysis for estimating reliability of a new type of system. The nine years of testing operations on TSTA's ETC result in a reasonable average availability value of 92% for the maximal tritium release event. The failure rates for new systems are expected to be lower than for the TSTA ETC, since improvements will be made in the design of the room air detritiation system based on the TSTA system experiences. Nonetheless, these TSTA data should be useful for future fusion reactor design work and safety assessment tasks

  10. Study on Endurance and Performance of Impregnated Ruthenium Catalyst for Thruster System.

    Science.gov (United States)

    Kim, Jincheol; Kim, Taegyu

    2018-02-01

    Performance and endurance of the Ru catalyst were studied for nitrous oxide monopropellant thruster system. The thermal decomposition of N2O requires a considerably high temperature, which make it difficult to be utilized as a thruster propellant, while the propellant decomposition temperature can be reduced by using the catalyst through the decomposition reaction with the propellant. However, the catalyst used for the thruster was frequently exposed to high temperature and high-pressure environment. Therefore, the state change of the catalyst according to the thruster operation was analyzed. Characterization of catalyst used in the operation condition of the thruster was performed using FE-SEM and EDS. As a result, performance degradation was occurred due to the volatilization of Ru catalyst and reduction of the specific surface area according to the phase change of Al2O3.

  11. A Systematic Modelling Framework for Phase Transfer Catalyst Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sales-Cruz, Mauricio; Hyung Kim, Sun

    2016-01-01

    Phase-transfer catalyst systems contain two liquid phases, with a catalyst (PTC) that transfers between the phases, driving product formation in one phase and being regenerated in the other phase. Typically the reaction involves neutral species in an organic phase and regeneration involves ions i....... The application of the framework is made to two cases in order to highlight the performance and issues of activity coefficient models for predicting design and operation and the effects when different organic solvents are employed....

  12. FY 1990 Study Meeting of Catalyst (Iron system). Data; 1990 nendo shokubai kento kai (Tetsu kei) shiryo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-03-01

    The FY 1990 Study Meeting of Iron-system Catalyst was held at NEDO on March 12, 1991, and the data were arranged. In the study meeting, papers titled as follows were made public: About the behavior of H{sub 2}S on iron-system catalyst by Muroran Institute of Technology; Results of the test on iron-system catalyst in the BCL project by Research Institute, Mitsubishi Kasei Corp.; Results of the test on iron-system catalyst by 2.4 t/d PDU by NKK; Results of the test on iron-system catalyst by 0.1 t/d BSU by Mitsui Engineering and Shipbuilding Co.; Results of the test on iron-system catalyst by 1 t/d PSU by Nippon Steel Corp.; Results of the research at Government Industrial Development Laboratory, Hokkaido, and the study; Results of the research at National Chemical Laboratory for Industry and the study; Results of the research at the University of Tokyo and the study; Details of the development of synthetic iron sulfide and the attainment up to now by Asahi Chemical Industry Co. Moreover, the plenary session was held on research items for the development of iron-system catalyst in future. (NEDO)

  13. Filter bag De-NOx system with powder type catalysts at low temperature

    International Nuclear Information System (INIS)

    Kim, Byung-Hwan; Kim, Jeong-Heon; Kang, Pil-Sun; Yoo, Seung-Kwan; Yoon, Kyoon-Duk

    2010-01-01

    Combustion of carbon source materials (MSW, RDF, sludge, coal etc.) leads to the emission of harmful gaseous pollutants such as SO x , NO x , mercury, particulate matter, and dioxins etc. In particular, the emission of nitrogen oxides (NO x ) from the solid waste incinerator remains a serious air pollution problem. The previous research concerns have focused mainly on NO x reduction of stationary sources at high temperature SCR or SNCR process. Selective catalytic reduction (SCR) with NH 3 is the most widespread system used to control NO x emissions. However, this process suffers from several disadvantages due to the use of thermo fragile honeycomb type module and high temperature (about 300 degree Celsius) operation which consumes additional heating energy. To overcome this hurdle, filter bag De-NO x system with powder type catalysts at low temperature (less than 200 degree Celsius) has been under investigation in recent years and looks interesting because neither additional heat nor honeycomb type modules are required. Filter bag and powder type catalysts are cheap and effective materials to remove NO x at low temperature. In this study, the selective catalytic reduction of NO x was carried out on a filter support reactor with 300 mesh powder type catalysts at low temperature. The experiments were performed by powder type MnO x and V 2 O 5 / TiO 2 catalyst at low temperature ranging between 130 and 250 degree Celsius. Also, the effect of SO 2 and H 2 O on the NO conversion was investigated under our test conditions. The powder type catalysts were characterized by X-ray photoelectron spectrum (XPS) for measuring the state of oxygen on the catalyst surface and X-ray diffraction (XRD). It was observed that NO conversion of the powder type V 2 O 5 / TiO 2 catalyst was 85 % at 200 degree Celsius under presence of oxygen and that of MnO x was 50 % at the same condition. From these results, the powder type V 2 O 5 / TiO 2 catalyst showed an excellent performance on the

  14. 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...... catalyst. The results from the screening were experimentally verified for CO hydrogenation, CO2 hydrogenation, and simultaneous CO and CO2 hydrogenation by bimetallic Ni-Fe catalysts. These catalysts were found to be highly active and selective. The Co-Ni and Co-Fe systems were investigated for CO...... 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...

  15. Development of high temperature metallic melting processes related to detritiation of exhausted control rods

    International Nuclear Information System (INIS)

    Dworschak, H.; Mannone, F.; Modica, G.

    1994-01-01

    A rather critical problem to be faced in developing a safe strategy for the management of tritiated solid wastes is dealing with the outgassing property of tritium. Releases of tritium under elemental or oxide form may occur from waste items at different temperatures and rates depending upon the nature of tritium bonds into the waste matrix as well as on its 'contamination history'. Apart from the commercial value of tritium, its release from waste packages anyhow represents a risk of tritium exposure that cannot be accepted by skippers, by store and disposal site operators as well as by the general public. Consequently it is mandatory to carry out the detritiation of such wastes before their packaging and storage or disposal. In the boron carbide control rods from the Lingen BWR after about three years of operation, tritium generated by neutron reaction was essentially retained in the B 4 C matrix. The objectives of the study are to demonstrate the feasibility of two processes aimed at reducing to the maximum practicable extent the level of tritium contamination in such waste management are facilitated

  16. Physico-chemical investigations in relation with the tritium circuit in fusion reactors

    International Nuclear Information System (INIS)

    Chabot, J.; Courvoisier, P.; Mauvisseau, J.; Sauzay, G.

    1986-06-01

    The tritium flow diagram within a fusion reactor may be splitted in a series of chemical engineering units. For them, the E.E.C. has launched a review program as well as experimental work. In this framework the CEA has carried out conceptual studies on fuel clean-up process, on gaseous waste treatment and on atmosphere detritiation systems. Moreover measurements with experimental loops are running to determine data necessary to assess unit dimensions; among others: hydrogen permeation rate through Pd-Ag membranes and tritium oxidation catalyst performances

  17. Engineered Sulfur‐Resistant Catalyst System with an Assisted Regeneration Strategy for Lean‐Burn Methane Combustion

    Science.gov (United States)

    Kallinen, Kauko; Maunula, Teuvo; Suvanto, Mika

    2018-01-01

    Abstract Catalytic combustion of methane, the main component of natural gas, is a challenge under lean‐burn conditions and at low temperatures owing to sulfur poisoning of the Pd‐rich catalyst. This paper introduces a more sulfur‐resistant catalyst system that can be regenerated during operation. The developed catalyst system lowers the barrier that has restrained the use of liquefied natural gas as a fuel in energy production. PMID:29780434

  18. Novel catalysts and photoelectrochemical system for solar fuel production

    Science.gov (United States)

    Zhang, Yan

    Solar fuel production from abundant raw chemicals such as CO2 and water is highly desired as a clean renewable energy solution for the future. Developing photoelectrochemical cells is viewed as a promising approach to realize this energy conversion and storage process. Efficient and robust oxygen evolution catalyst made from non-precious materials remains a major challenge for such a system. This thesis basically consists of three parts of work, including studies on enhancing the photocatalytic oxygen evolution activity of cobalt-based spinel nanoparticles by manganese3+ substitution, in situ formation of cobalt oxide nanocubanes as highly active catalyst for photocatalytic oxygen evolution reaction, and development of a photoanode-driven photoelectrochemical cell for CO2 reduction with water. The first part of this thesis work devotes efforts in the development and study on cobalt and other transition metal oxide based oxygen evolution catalyst. Photocatalytic oxygen evolution is a critical step for solar fuel production from abundant sources. It poses a significant challenge because it requires an efficient catalyst to bridge the one-electron photon capture process with the four-electron oxygen reaction. Among all the metal oxides, Co3O4 spinel exhibits a high activity as an oxygen evolution catalyst. The results of this work demonstrate that the photocatalytic oxygen evolution activity of Co3O4 spinel can be further enhanced by substituting Co with Mn in the spinel structure. Using a facile hydrothermal approach, Co3O4 spinel nanoparticles as well as Mn-substituted and Ni-substituted Co3O4 spinel nanoparticles with a typical particle size of 5-7 nm were successfully synthesized. The morphology and crystal structures of the as-synthesized nanoparticle catalysts have been carefully examined using various structural characterization techniques, including powder x-ray diffraction (PXRD), transmission electron microscope (TEM), gas adsorption, and x-ray absorption

  19. Techniques for tritium recovery from carbon flakes and dust at the JET active gas handling system

    International Nuclear Information System (INIS)

    Gruenhagen, S.; Perevezentsev, A.; Brennan, P. D.; Camp, P.; Knipe, S.; Miller, A.; Yorkshades, J.

    2008-01-01

    Detritiation of highly tritium contaminated carbon and metal material used as first wall armour is a key issue for fusion machines like JET and ITER. Re-deposited carbon and hydrogen in the form of flakes and dust can lead to a build-up of the tritium inventory and therefore this material must be removed and processed. The high tritium concentration of the flake and dust material collected from the JET vacuum vessel makes it unsuitable for direct waste disposal without detritiation. A dedicated facility to process the tritiated carbon flake material and recover the tritium has been designed and built. In several test runs active material was successfully processed and de-tritiated in the new facility. Samples containing only carbon and hydrogen isotopes have been completely oxidized without any residue. Samples containing metallic impurities, e.g. beryllium, require longer processing times, adjusted processing parameters and yield an oxide residue. The detritiation factor was 2x10 4 . In order to simulate in-vessel and ex-vessel detritiation techniques, the detritiation of a carbon flake sample by isotopic exchange in a hydrogen atmosphere was investigated. 2.8% of tritium was recovered by this means. (authors)

  20. Preparation of ethylene/1-hexene copolymers from ethylene using a fully silica-supported tandem catalyst system

    NARCIS (Netherlands)

    Karbach, Fabian F.; Macko, Tibor; Duchateau, Robbert

    2016-01-01

    A silica-supported tandem catalyst system, capable of producing ethylene/1-hexene copolymers from ethylene being the single monomer, has been investigated. As tandem couple a phenoxyimine titanium catalyst for ethylene trimerization was combined with a metallocene catalyst for α-olefin

  1. Overview of R and D activities on tritium processing and handling technology in JAEA

    Energy Technology Data Exchange (ETDEWEB)

    Yamanishi, Toshihiko, E-mail: yamanishi.toshihiko@jaea.go.jp [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Oyaidsu, Makoto; Yamada, Masayuki; Suzuki, Takumi; Hayashi, Takumi [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The tritium technologies have been studied at Tritium Process Laboratory of JAEA. Black-Right-Pointing-Pointer A monitoring method for the blanket system of a fusion reactor have been studied. Black-Right-Pointing-Pointer Basic studies on the tritium behavior in confinement system have been carried out. Black-Right-Pointing-Pointer Studies on the detritiation have been carried out as another significant activity. - Abstract: In JAEA, the tritium processing and handling technologies have been studied at TPL (Tritium Process Laboratory). The main R and D activities are: the tritium processing technology for the blanket recovery systems; the basic tritium behavior in confinement materials; and detritiation and decontamination. The R and D activities on tritium processing and handling technologies for a demonstration reactor (DEMO) are also planned to be carried out in the broader approach (BA) program by JAEA with Japanese universities. The ceramic proton conductor has been studied as a possible tritium processing method for the blanket system. The BIXS method has also been studied as a monitoring of tritium in the blanket system. The hydrogen transfer behavior from water to metal has been studied as a function of temperature. As for the behavior of high concentration tritium water, it was observed that the formation of the oxidized layer was prevented by the presence of tritium in water (0.23 GBq/cc). A new hydrophobic catalyst has been developed for the conversion of tritium to water. The catalyst could convert tritium to water at room temperature. A new Nafion membrane has also been developed by gamma ray irradiation to get the strong durability for tritium.

  2. 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.

  3. Sodium borohydride hydrogen generator using Co–P/Ni foam catalysts for 200 W proton exchange membrane fuel cell system

    International Nuclear Information System (INIS)

    Oh, Taek Hyun; Gang, Byeong Gyu; Kim, Hyuntak; Kwon, Sejin

    2015-01-01

    The response characteristics of electroless-deposited Co–P/Ni foam catalysts for sodium borohydride hydrolysis were investigated. The effect of nickel foam geometry on the properties of the catalysts was evaluated. As the PPI (pores per inch) of the nickel foam increased, the hydrogen generation rate per gram of the deposited catalyst increased due to an increase in surface area. The response characteristics of various catalysts were compared under real operating conditions. When a thin nickel foam with high PPI was used, the response characteristics of the catalyst improved due to an increase in the amount of the deposited catalyst and surface area. Finally, a 200 W PEMFC (proton exchange membrane fuel cell) system using electroless-deposited Co–P/Ni foam (110 PPI) catalyst was investigated. The response time to reach a hydrogen generation rate sufficient for a 200 W PEMFC was 71 s, and the energy density of a 200 W fuel cell system for producing 600 Wh was 252.1 Wh/kg. A fuel cell system using Co–P/Ni foam catalysts can be widely used as a power source for mobile applications due to fast response characteristics and high energy density. - Highlights: • Response characteristics of Co–P/Ni foam catalysts are investigated. • Catalytic activity is improved with increase in PPI (pores per inch) of Ni foam. • Co–P/Ni foam (110 PPI) catalyst has improved response characteristics. • The energy density of a 200 W PEMFC system for producing 600 Wh is 252.1 Wh/kg. • Co–P/Ni foam (110 PPI) catalyst is suitable for fuel cell system.

  4. Non-Precious Bimetallic Catalysts for Selective Dehydrogenation of an Organic Chemical Hydride System

    KAUST Repository

    Shaikh Ali, Anaam

    2015-07-06

    Methylcyclohexane (MCH)-Toluene (TOL) chemical hydride cycles as a hydrogen carrier system is successful with the selective dehydrogenation reaction of MCH to TOL, which has been achieved only using precious Pt-based catalysts. Herein, we report improved selectivity using non-precious metal nickel-based bimetallic catalysts, where the second metal occupies the unselective step sites.

  5. A novel process for heavy residue hydroconversion using a recoverable pseudo-homogenous catalyst PHC system

    Energy Technology Data Exchange (ETDEWEB)

    Romocki, S.M.; Rhodey, W.G. [Mobis Energy Inc., Calgary, AB (Canada)

    2008-10-15

    This paper described a pseudo-homogenous catalyst (PHC) designed to refine heavy hydrocarbon residues containing sulfur, nitrogen, metals, and asphaltene impurities known to clog pores and deactivate traditional hydrocrackers. The heavy residue hydroconversion (HRH) process incorporated a single particle, chemically generated PHC uniformly distributed in the feed. Thermal decomposition within the reaction system of a water-in-oil emulsion containing ammonium paramolybdate was used to form molybdenum oxide, which was then sulfided within the feed in order to create an ultra-dispersed suspension of catalytically active molybdenum disulfide particles measuring between 2 and 9 nm. A proprietary online catalyst recovery and regeneration step was used to maintain high catalyst activity. The molybdenum was then recovered from a purge stream and then reintroduced to the catalyst preparation area as a catalyst precursor. After being conditioned, the feed was combined with hydrogen and a water-oil catalyst emulsion and introduced into a furnace. Heavy components were cracked, hydrogenated and converted to lighter products. The high performance catalyst system was able to convert 95 per cent of residues at pressures below 7.3 Mpa and at reaction temperatures ranging between 400 and 460 degrees C. The catalyst was tested at a pilot plant using Athabasca vacuum bottoms. It was concluded that the HRH process is now being successfully used to produce 200 barrels of heavy oil per day. Designs for commercial installations are now being prepared. 4 refs., 2 tabs., 2 figs.

  6. In situ Generated Ruthenium Catalyst Systems Bearing Diverse N-Heterocyclic Carbene Precursors for Atom-Economic Amide Synthesis from Alcohols and Amines.

    Science.gov (United States)

    Cheng, Hua; Xiong, Mao-Qian; Cheng, Chuan-Xiang; Wang, Hua-Jing; Lu, Qiang; Liu, Hong-Fu; Yao, Fu-Bin; Chen, Cheng; Verpoort, Francis

    2018-02-16

    The transition-metal-catalyzed direct synthesis of amides from alcohols and amines is herein demonstrated as a highly environmentally benign and atom-economic process. Among various catalyst systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalyst systems have been proven to be active for this transformation. However, these existing catalyst systems usually require an additional ligand to achieve satisfactory results. In this work, through extensive screening of a diverse variety of NHC precursors, we discovered an active in situ catalyst system for efficient amide synthesis without any additional ligand. Notably, this catalyst system was found to be insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalyst systems, could be employed to afford the corresponding amides efficiently. Furthermore, mechanistic investigations were performed to provide a rationale for the high activity of the optimized catalyst system. NMR-scale reactions indicated that the rapid formation of a Ru hydride intermediate (signal at δ=-7.8 ppm in the 1 H NMR spectrum) after the addition of the alcohol substrate should be pivotal in establishing the high catalyst activity. Besides, HRMS analysis provided possible structures of the in situ generated catalyst system. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Development of high performance catalyst for off-gas treatment system in BWR

    International Nuclear Information System (INIS)

    Kawasaki, Toru; Kawabe, Kenichi; Maeda, Kiyomitsu; Matsubara, Hirofumi; Aizawa, Motohiro; Iizuka, Hidehiro; Kumagai, Naoki

    2011-01-01

    A high performance catalyst for off-gas treatment system in boiling water reactor (BWR) has been developed. The hydrogen concentration in the outlets of off-gas recombiners increased at several BWR plants in Japan. These phenomena were caused by deactivation of catalysts for the recombiners, and we assumed two types of deactivation mechanisms. The first cause was an increase of the amount of boehmite in the catalyst support due to alternation of the manufacturing process. The other cause was catalysts being poisoned by cyclic siloxanes that were introduced from the silicone sealant used in the upstream of the off-gas recombiners. The catalysts were manufactured by Pt adhering on alumina support. The conventional catalyst (CAT-A) used the aqueous solution of the chloroplatinic acid for adhesion of Pt. A dechlorination process by autoclave was applied to prevent the equipment at the downstream of the recombiners from stress corrosion cracking, but this process caused the support material to transform into boehmite. The boehmite-rich catalysts were deactivated more easily by organic silicon than gamma alumina-rich catalysts. Therefore, the CAT-A was replaced at many Japanese BWR plants by the improved catalyst (CAT-B), and their support was transformed into more stable gamma alumina by heating at 500degC. However, the siloxanes keep being detected in the off-gas though the source of siloxane had been removed and there still remain possibilities to deactivate the catalysts. Therefore, we have been developing high performance catalyst (CAT-C) that has higher activity and durability against poisoning. We investigated the properties of CAT-C by performance tests and instrumental analyses. The dependency of thermal output of nuclear reactor, and durability against siloxane poisoning were investigated. We found that CAT-C showed higher performance and better properties than CAT-B did. Moreover, we have been developing a modeling method to evaluate the hydrogen recombination

  8. Intracellular Chemistry: Integrating Molecular Inorganic Catalysts with Living Systems.

    Science.gov (United States)

    Ngo, Anh H; Bose, Sohini; Do, Loi H

    2018-03-23

    This concept article focuses on the rapid growth of intracellular chemistry dedicated to the integration of small-molecule metal catalysts with living cells and organisms. Although biological systems contain a plethora of biomolecules that can deactivate inorganic species, researchers have shown that small-molecule metal catalysts could be engineered to operate in heterogeneous aqueous environments. Synthetic intracellular reactions have recently been reported for olefin hydrogenation, hydrolysis/oxidative cleavage, azide-alkyne cycloaddition, allylcarbamate cleavage, C-C bond cross coupling, and transfer hydrogenation. Other promising targets for new biocompatible reaction discovery will also be discussed, with a special emphasis on how such innovations could lead to the development of novel technologies and chemical tools. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Detritiation of Tritiated Effluent Gas and Water

    International Nuclear Information System (INIS)

    Ahn, Do Hee; Kim, Kwang Rag; Paek, Seung Woo; Lee, Min Soo; Yim, Sung Paal; Chung Hong Suk

    2007-06-01

    In a demonstration scale equipment for treatment of tritium in off-gas, Pt/SDBC as oxidation catalyst and Zeolite 13X as adsorbent was charged in the beds, respectively. It was confirmed from the performance test that decontamination factor of the equipment showed more than 100 under the flow rate of off-gas of 90 l/hr and at the temperature of 65 ∼ 80 .deg. C. A small scale CECE process has been developed combining LPCE catalytic column with SPE (solid polymer electrolyte) electrolysis. The catalytic column was a trickle-bed type packed with the mixture of 1 wt% Pt/SDBC catalyst and 4 mm Dixon wire-mesh ring. The experimental results of the CECE process proved that the decontamination factor of 13 ∼ 20 under the operating conditions of the water of the 4 l/day and the effluent hydrogen gas of 16.2 mol/h. A design code of CECE process also developed which will be applied the tritium industry. An experimental method for the reduction of tritiated organic waste by using catalytic oxidation was tested in a heated catalytic reactor of 0.5 wt% Pd/Al 2 O 3 . The simulated organic liquid was converted to water over 99%. A gas chromatographic column material was developed for the separation of mixed hydrogen isotopes. 17 wt% Pd-Pt on alumina showed 90% separation efficiency at 77 % yield for the separation of 29.2 % D 2 -H 2 gas mixture

  10. Detritiation of Tritiated Effluent Gas and Water

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Do Hee; Kim, Kwang Rag; Paek, Seung Woo; Lee, Min Soo; Yim, Sung Paal; Chung Hong Suk

    2007-06-15

    In a demonstration scale equipment for treatment of tritium in off-gas, Pt/SDBC as oxidation catalyst and Zeolite 13X as adsorbent was charged in the beds, respectively. It was confirmed from the performance test that decontamination factor of the equipment showed more than 100 under the flow rate of off-gas of 90 l/hr and at the temperature of 65 {approx} 80 .deg. C. A small scale CECE process has been developed combining LPCE catalytic column with SPE (solid polymer electrolyte) electrolysis. The catalytic column was a trickle-bed type packed with the mixture of 1 wt% Pt/SDBC catalyst and 4 mm Dixon wire-mesh ring. The experimental results of the CECE process proved that the decontamination factor of 13 {approx} 20 under the operating conditions of the water of the 4 l/day and the effluent hydrogen gas of 16.2 mol/h. A design code of CECE process also developed which will be applied the tritium industry. An experimental method for the reduction of tritiated organic waste by using catalytic oxidation was tested in a heated catalytic reactor of 0.5 wt% Pd/Al{sub 2}O{sub 3}. The simulated organic liquid was converted to water over 99%. A gas chromatographic column material was developed for the separation of mixed hydrogen isotopes. 17 wt% Pd-Pt on alumina showed 90% separation efficiency at 77 % yield for the separation of 29.2 % D{sub 2}-H{sub 2} gas mixture.

  11. Laser detritiation and co-deposited layer characterisation for future ITER Installation

    International Nuclear Information System (INIS)

    Semerok, Alexandre; Brygo, Francois; Fomichev, Sergey V.; Champonnois, Francois; Weulersse, Jean-Marc; Thro, Pierre-Yves; Fichet, Pascal; Grisolia, Christian

    2006-01-01

    The experimental equipment in combination with pulsed Nd-YAG lasers was developed and applied to investigate co-deposited layer characterisation and ablation. Heating and ablation regimes were distinguished by ablation threshold fluence that was determined experimentally for graphite samples from TexTor (Germany) and TORE SUPRA (France) tokamaks. With 100 ns pulses, the ablation threshold for graphite substrate (2.5±0.5 J/cm 2 ) was much higher than the one for co-deposited layer (0.4±0.1 J cm -2 ). These threshold features are very promising to ensure self-controlled laser cleaning without substrate surface damage. The obtained optimal conditions (laser fluence F=1-2 J/cm 2 , 10-20 kHz repetition rate) were applied for co-deposited layer cleaning. The TexTor 50 μm thickness layer was almost completely removed after a single scanning without any damage of the graphite substrate. Cleaning rate of 0.2 m 2 /hour was demonstrated experimentally for 20 W mean laser power. A theoretical model of a complex surface heating (graphite or metal with a co-deposited layer) was developed to explain the experimental results and to obtain laser cleaning optimisation. A good agreement of the theoretical data with the experimental results was obtained. The studies on LIBS method for co-deposited layer characterisation have determined the analytical spectral lines for hydrogen, carbon, and other impurities (B, Fe, Si, and Cu) in TexTor graphite tile. The obtained results should be regarded optimistic for co-deposited layers characterisation by LIBS method. The development of certain laser methods and their application for in-situ detritiation and co-deposited layer characterisation are presented and discussed. (authors)

  12. Tritium-related fusion technology programmes under EFDA-JET

    International Nuclear Information System (INIS)

    Coad, J. P.; Ciattaglia, S.; Piazza, G.; Rosanvallon, S.; Grisolia, Ch.; Laesser, R.

    2003-01-01

    The Fusion Technology Task Force (TFFT) has a wide-ranging series of programmes in the areas of waste management and safety, tritium recovery, tritium analysis and accounting, and testing components under development for ITER at JET. Examples have been presented here in the fields of waste management and safety. In waste management, the largest effort is currently on water de-tritiation, which is considered to be the most urgent and important topic affecting JET operations, and plant design is also required for ITER. It is also the most technically challenging of the waste detritiation issues. A complete design for a water de-tritiation plant for JET (a prototype for ITER), including optimised and tested catalysts, is expected within the next 2 years. TFFT safety programmes support the on-going work on safety in preparation for ITER, including tritium spreading and dust inhalation effects for worse-case accident scenarios. Effort is also going into documenting the operational experience of the JET machine with respect to reliability of mechanical components within the tritium boundary and radiation exposure, and inferring what lessons should be learnt for ITER

  13. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Ahmmed Saadi Ibrehem

    2011-11-01

    Full Text Available In this work, system identification method is used to capture the reactor characteristics of production rate of polyethylene (PE based on published experimental data. The identification method is used to measure the percentage effect on the production rate of PE by measuring the effect of input factors of temperature of reaction, hydrogen concentration, and [Al]/[Ti] molar catalyst ratio. Temperature of reaction has big effects equal 52.4 % on the output of the system and 47.6 % on interaction of the system's parameters compare to other two factors. Also, hydrogen concentration has big effect equal 45.66 % on the output of the system and 14.7 % on interaction of the system's parameters. [Al]/[Ti] molar catalyst ratio has big effect on interaction of the system equal 28.6 and 1.94 % on the output of the system but less than the reaction temperature and hydrogen concentration. All these results depend on experiment results and these results are very important in industrial plants. ©2011 BCREC UNDIP. All rights reserved(Received: 13rd May 2011; Revised: 27th July 2011; Accepted: 22th September 2011[How to Cite: Ahmmed S. Ibrehem. (2011. System Identification for Experimental Study for Polymerization Catalyst Reaction in Fluidized Bed. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 137-146. doi:10.9767/bcrec.6.2.874.137-146][How to Link / DOI: http://dx,doi.org/10.9767/bcrec.6.2.874.137-146 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/874 ] | View in 

  14. Production of perovskite catalysts on ceramic monoliths with nanoparticles for dual fuel system automobiles

    International Nuclear Information System (INIS)

    Khanfekr, A.; Arzani, K.; Nemati, A.; Hosseini, M.

    2009-01-01

    (Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen) 3 ,-Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with X U 7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as Palladium, Platinum and Rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of carbon monoxide, nitrogen oxides and hydrocarbons were lower than imported catalyst with Iran Khodro company with nobel metals. The illustration shows nano particles size on coat. The microstructure evaluation showed that the improved properties can be related to the existence of nano particles on coating

  15. Method of preparing and utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream

    Science.gov (United States)

    Berry, David A; Shekhawat, Dushyant; Smith, Mark; Haynes, Daniel

    2013-07-16

    The disclosure relates to a method of utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream with a mitigation of carbon accumulation. The system is comprised of a catalytically active phase deposited onto an oxygen conducting phase, with or without supplemental support. The catalytically active phase has a specified crystal structure where at least one catalytically active metal is a cation within the crystal structure and coordinated with oxygen atoms within the crystal structure. The catalyst system employs an optimum coverage ratio for a given set of oxidation conditions, based on a specified hydrocarbon conversion and a carbon deposition limit. Specific embodiments of the catalyst system are disclosed.

  16. Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

    Directory of Open Access Journals (Sweden)

    Galip Akay

    2016-05-01

    Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

  17. System and method for determining an ammonia generation rate in a three-way catalyst

    Science.gov (United States)

    Sun, Min; Perry, Kevin L; Kim, Chang H

    2014-12-30

    A system according to the principles of the present disclosure includes a rate determination module, a storage level determination module, and an air/fuel ratio control module. The rate determination module determines an ammonia generation rate in a three-way catalyst based on a reaction efficiency and a reactant level. The storage level determination module determines an ammonia storage level in a selective catalytic reduction (SCR) catalyst positioned downstream from the three-way catalyst based on the ammonia generation rate. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the ammonia storage level.

  18. Catalysts for synthetic liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, L.A.; Turney, T.W.

    1987-12-01

    Fischer-Tropsch catalysts have been designed, characterized and tested for the selective production of hydrocarbons suitable as synthetic liquid transport fuels from synthesis gas (i.e., by the reduction of carbon monoxide with hydrogen). It was found that hydrocarbons in the middle distillate range, or suitable for conversion to that range, could be produced over several of the new catalyst systems. The various catalysts examined included: (1) synthetic cobalt clays, mainly cobalt chlorites; (2) cobalt hydrotalcites; (3) ruthenium metal supported on rare earth oxides of high surface area; and (4) a novel promoted cobalt catalyst. Active and selective catalysts have been obtained, in each category. With the exception of the clays, reproducibility of catalyst performance has been good. Catalysts in groups 2 and 4 have exhibited very high activity, with long lifetimes and easy regeneration.

  19. A Highly Practical Copper(I)/TEMPO Catalyst System for Chemoselective Aerobic Oxidation of Primary Alcohols

    Science.gov (United States)

    Hoover, Jessica M.; Stahl, Shannon S.

    2011-01-01

    Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O2 as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)CuI/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary alcohols, including allylic, benzylic and aliphatic derivatives, to the corresponding aldehydes using readily available reagents, at room temperature with ambient air as the oxidant. The catalyst system is compatible with a wide range of functional groups and the high selectivity for 1° alcohols enables selective oxidation of diols that lack protecting groups. PMID:21861488

  20. On use of beryllium in fusion reactors: Resources, impurities and necessity of detritiation after irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kolbasov, B.N., E-mail: b.kolbasov@yandex.ru; Khripunov, V.I., E-mail: Khripunov_VI@nrcki.ru; Biryukov, A.Yu.

    2016-11-01

    Highlights: • Potential needs in Be for fusion power engineering may exceed Be resources. • Be recycling after its operation in a fusion power plant (FPP) seems inevitable. • U impurity in Be seriously impairs environmental properties of fusion power plants. • Upon burial of irradiated Be the main problems are caused by U and {sup 3}H impurities. • Clearance of Be extracted from a FPP is impossible due to U impurity. - Abstract: Worldwide identified resources of beryllium somewhat exceed 80 000 t. Beryllium production in all the countries of the world in 2012 was about 230 t. At the same time, some conceptual designs of fusion power reactors envisage utilization of several hundred tons of this metal. Therefore return of beryllium into the production cycle (recycling) will be necessary. The beryllium ore from some main deposits has uranium content inadmissible for fusion reactors. This fact raises a question on the need to develop and apply an economically acceptable technology for beryllium purification from the uranium. Practically any technological procedure with beryllium used in fusion reactors requires its detritiation. A study of tritium and helium release from irradiated beryllium at different temperatures and rates of temperature increase was performed at Kurchatov Institute.

  1. Multi-level computational chemistry study on hydrogen recombination catalyst of off-gas treatment system

    International Nuclear Information System (INIS)

    Hatakeyama, Nozomu; Ise, Mariko; Inaba, Kenji

    2011-01-01

    In order to reveal the deactivation mechanism of the hydrogen recombination catalyst of off-gas treatment system, we investigate by using multi-level computational chemistry simulation methods. The recombiner apparatus is modeled by the numerical mesh system in the axial coordinates, and unsteady, advection and reaction rate equations are solved by using a finite difference method. The chemical reactions are formulated to represent adsorption-desorption of hydrogen and oxygen on Pt catalyst, and time developments of the coverage factors of Pt are solved numerically. The computational simulations successfully reproduce the very similar behaviors observed by experiments, such as increasing of the inversion rates of H 2 to H 2 O, the temperatures distributions along the flow direction, dependencies of experimental condition, and so on. Thus Pt poisoning is considered to cause the deactivation of the hydrogen recombination catalyst. To clarify the poisoning mechanism, the molecular level simulation is applied to the system of Pt on boehmite attacked by a cyclic siloxane which has been detected by experiments and considered as one of poisoning spices. The simulation shows ring-opening reaction of the cyclic siloxane on Pt, then attachment of two ends of the chain-like siloxane to Pt and boehmite, respectively, and that finally the recombination reaction is prevented. This may be the first study to find out the detailed dynamical mechanism of hydrogen recombination catalyst poisoning with cyclic siloxane. (author)

  2. Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices.

    Science.gov (United States)

    Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

    2017-06-09

    A covalently linked organic dye-cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye-sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time-resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on the photocathode is proposed on the basis of this study. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  3. 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.

  4. CFFTP journal volume 9 no. 1

    International Nuclear Information System (INIS)

    1992-11-01

    A short journal article from Canadian Fusion Fuels Technology Project (CFFTP) highlighting the Canadian Nuclear Association Seminar, the Tritium purification system for Princeton Plasma Physics Laboratory, TFTR exhaust gas detritiation, the CFFTP pilot plant study, the Hitex impurity detritiation system and lithium titanate studies

  5. PILOT TESTING OF MERCURY OXIDATION CATALYSTS FOR UPSTREAM OF WET FGD SYSTEMS

    International Nuclear Information System (INIS)

    Gary M. Blythe

    2002-01-01

    The objective of this project is to demonstrate at pilot scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in the flue gas from coal combustion. The project is being funded by the U.S. DOE National Energy Technology Laboratory under Cooperative Agreement DE-FC26-01NT41185. EPRI, Great River Energy (GRE), and City Public Service (CPS) of San Antonio are project co-funders. URS Group is the prime contractor. The mercury catalytic oxidation process under development uses catalyst materials applied to honeycomb substrates to promote the oxidation of elemental mercury in the flue gas from coal-fired power plants that have wet lime or limestone flue gas desulfurization (FGD) systems. Oxidized mercury is removed in the wet FGD absorbers and co-precipitates in a stable form with the byproducts from the FGD system. The co-precipitated mercury does not appear to adversely affect the disposal or reuse properties of the FGD byproduct. The current project will test previously identified, effective catalyst materials at a larger, pilot scale and in a commercial form, so as to provide engineering data for future full-scale designs. The pilot-scale tests will continue for up to 14 months at each of two sites to provide longer-term catalyst life data. This is the first full reporting period for the subject Cooperative Agreement. During this period, most of the project efforts were related to project initiation and planning. There is no significant technical progress to report for the current period

  6. Recent progress in solution plasma-synthesized-carbon-supported catalysts for energy conversion systems

    Science.gov (United States)

    Lun Li, Oi; Lee, Hoonseung; Ishizaki, Takahiro

    2018-01-01

    Carbon-based materials have been widely utilized as the electrode materials in energy conversion and storage technologies, such as fuel cells and metal-air batteries. In these systems, the oxygen reduction reaction is an important step that determines the overall performance. A novel synthesis route, named the solution plasma process, has been recently utilized to synthesize various types of metal-based and heteroatom-doped carbon catalysts. In this review, we summarize cutting-edge technologies involving the synthesis and modeling of carbon-supported catalysts synthesized via solution plasma process, followed by current progress on the electrocatalytic performance of these catalysts. This review provides the fundamental and state-of-the-art performance of solution-plasma-synthesized electrode materials, as well as the remaining scientific and technological challenges for this process.

  7. 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.

  8. Development of Molecular Catalysts to Bridge the Gap between Heterogeneous and Homogeneous Catalysts

    Science.gov (United States)

    Ye, Rong

    be versatile scaffolds for the synthesis and stabilization of small nanoclusters. Then these dendrimer-encapsulated metal clusters (DEMCs) are adsorbed onto mesoporous silica. Through this method, we have achieved selective transformations that had been challenging to accomplish in a heterogeneous setting, e.g. pi-bond activation and aldol reactions. Extensive investigation into the catalytic systems under reaction conditions allowed us to correlate the structural features (e.g. oxidation states) of the catalysts and their activity. Moreover, we have demonstrated that supported DEMCs are also excellent catalysts for typical heterogeneous reactions, including hydrogenation and alkane isomerization. Critically, these investigations also confirmed that the supported DEMCs are heterogeneous and stable against leaching. Catalysts optimization is achieved through the modulation of various parameters. The clusters are oxidized (e.g., with PhICl2) or reduced (e.g., with H2) in situ. Changing the dendrimer properties (e.g., generation, terminal functional groups) is analogous to ligand modification in homogeneous catalysts, which affect both catalytic activity and selectivity. Similarly, pore size of the support is another factor in determining product distribution. In a flow reactor, the flow rate is adjusted to control the residence time of the starting material and intermediates, and thus the final product selectivity. Our approach to heterogeneous catalysis affords various advantages: (1) the catalyst system can tap into the reactivity typical to homogeneous catalysts, which conventional heterogeneous catalysts could not achieve; (2) unlike most homogeneous catalysts with comparable performance, the heterogenized homogeneous catalysts can be recycled; (3) improved activity or selectivity compared to conventional homogeneous catalysts is possible because of uniquely heterogeneous parameters for optimization. While localized surface plasmon resonance (LSPR) provides a

  9. 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.

  10. The ITER tritium systems

    International Nuclear Information System (INIS)

    Glugla, M.; Antipenkov, A.; Beloglazov, S.; Caldwell-Nichols, C.; Cristescu, I.R.; Cristescu, I.; Day, C.; Doerr, L.; Girard, J.-P.; Tada, E.

    2007-01-01

    ITER is the first fusion machine fully designed for operation with equimolar deuterium-tritium mixtures. The tokamak vessel will be fuelled through gas puffing and pellet injection, and the Neutral Beam heating system will introduce deuterium into the machine. Employing deuterium and tritium as fusion fuel will cause alpha heating of the plasma and will eventually provide energy. Due to the small burn-up fraction in the vacuum vessel a closed deuterium-tritium loop is required, along with all the auxiliary systems necessary for the safe handling of tritium. The ITER inner fuel cycle systems are designed to process considerable and unprecedented deuterium-tritium flow rates with high flexibility and reliability. High decontamination factors for effluent and release streams and low tritium inventories in all systems are needed to minimize chronic and accidental emissions. A multiple barrier concept assures the confinement of tritium within its respective processing components; atmosphere and vent detritiation systems are essential elements in this concept. Not only the interfaces between the primary fuel cycle systems - being procured through different Participant Teams - but also those to confinement systems such as Atmosphere Detritiation or those to fuelling and pumping - again procured through different Participant Teams - and interfaces to buildings are calling for definition and for detailed analysis to assure proper design integration. Considering the complexity of the ITER Tritium Plant configuration management and interface control will be a challenging task

  11. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael [Naperville, IL; Liu, Di-Jia [Naperville, IL

    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.

  12. Hydrogen isotope separation for fusion power applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R., E-mail: robert.smith@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Whittaker, D.A.J.; Butler, B.; Hollingsworth, A.; Lawless, R.E.; Lefebvre, X.; Medley, S.A.; Parracho, A.I.; Wakeling, B. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2015-10-05

    Highlights: • Summary of the tritium plant, the Active Gas Handling System (AGHS), at JET. • Review of the Water Detritiation System (WDS) under construction. • Design of the new Material Detritiation Facility (MDF). • Review of problems in fusion related to metal/hydrogen system. - Abstract: The invited talk given at MH2014 in Salford ranged over many issues associated with hydrogen isotope separation, fusion machines and the hydrogen/metal systems found in the Joint European Torus (JET) machine located near Oxford. As this sort of talk does not lend itself well to a paper below I have attempted to highlight some of the more pertinent information. After a description of the Active Gas Handling System (AGHS) a brief summary of isotope separation systems is described followed by descriptions of three major projects currently being undertaken by the Tritium Engineering and Science Group (TESG), the upgrade to the Analytical Systems (AN-GC) at the AGH, the construction of a Water Detritiation System (WDS) and a Material Detritiation Facility (MDF). Finally, a review of some of the challenges facing fusion with respect to metal/hydrogen systems is presented.

  13. Design of Embedded Metal Catalysts via Reverser Micro-Emulsion System: a Way to Suppress Catalyst Deactivation by Metal Sintering

    KAUST Repository

    AlMana, Noor

    2016-06-19

    The development of highly selective and active, long-lasting, robust, low-cost and environmentally benign catalytic materials is the greatest challenge in the area of catalysis study. In this context, core-shell structures where the active sites are embedded inside the protecting shell have attracted a lot of researchers working in the field of catalysis owing to their enhanced physical and chemical properties suppress catalyst deactivation. Also, a new active site generated at the interface between the core and shell may increases the activity and efficiency of the catalyst in catalytic reactions especially for oxide shells that exhibit redox properties such as TiO2 and CeO2. Moreover, coating oxide layer over metal nanoparticles (NPs) can be designed to provide porosity (micropore/mesopore) that gives selectivity of the various reactants by the different gas diffusion rates. In this thesis, we will discuss the concept of catalyst stabilization against metal sintering by a core-shell system. In particular we will study the mechanistic of forming core-shell particles and the key parameters that can influence the properties and morphology of the Pt metal particle core and SiO2 shell (Pt@SiO2) using the reverse micro-emulsion method. The Pt@SiO2 core-shell catalysts were investigated for low-temperature CO oxidation reaction. The study was further extended to other catalytic applications by varying the composition of the core as well as the chemical nature of the shell material. The Pt NPs were embedded within another oxide matrix such as ZrO2 and TiO2 for CO oxidation reaction. These materials were studied in details to identify the factors governing the coating of the oxide around the metal NPs. Next, a more challenging system, namely, bimetallic Ni9Pt NPs embedded in TiO2 and ZrO2 matrix were investigated for dry reforming of methane reaction at high temperatures. The challenges of designing Ni9Pt@oxide core-shell structure with TiO2 and ZrO2 and their tolerance

  14. High-throughput reactor system with individual temperature control for the investigation of monolith catalysts

    Science.gov (United States)

    Dellamorte, Joseph C.; Vijay, Rohit; Snively, Christopher M.; Barteau, Mark A.; Lauterbach, Jochen

    2007-07-01

    A high-throughput parallel reactor system has been designed and constructed to improve the reliability of results from large diameter catalysts such as monoliths. The system, which is expandable, consists of eight quartz reactors, 23.5mm in diameter. The eight reactors were designed with separate K type thermocouples and radiant heaters, allowing for the independent measurement and control of each reactor temperature. This design gives steady state temperature distributions over the eight reactors within 0.5°C of a common setpoint from 50to700°C. Analysis of the effluent from these reactors is performed using rapid-scan Fourier transform infrared (FTIR) spectroscopic imaging. The integration of this technique to the reactor system allows a chemically specific, truly parallel analysis of the reactor effluents with a time resolution of approximately 8s. The capabilities of this system were demonstrated via investigation of catalyst preparation conditions on the direct epoxidation of ethylene, i.e., on the ethylene conversion and the ethylene oxide selectivity. The ethylene, ethylene oxide, and carbon dioxide concentrations were calibrated based on spectra from FTIR imaging using univariate and multivariate chemometric techniques. The results from this analysis showed that the calcination conditions significantly affect the ethylene conversion, with a threefold increase in the conversion when the catalyst was calcined for 3h versus 12h at 400°C.

  15. Sabatier Catalyst Poisoning Investigation

    Science.gov (United States)

    Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

    2013-01-01

    The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

  16. System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

    Science.gov (United States)

    Sun, MIn; Perry, Kevin L.

    2015-11-20

    A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

  17. ITER fuel cycle systems layout

    International Nuclear Information System (INIS)

    Kveton, O.K.

    1990-10-01

    The ITER fuel cycle building (FCB) will contain the following systems: fuel purification - permeator based; fuel purification - molecular sieves; impurity treatment; waste water storage and treatment; isotope separation; waste water tritium extraction; tritium extraction from solid breeder; tritium extraction from test modules; tritium storage, shipping and receiving; tritium laboratory; atmosphere detritiation systems; fuel cycle control centre; tritiated equipment maintenance space; control maintenance space; health physics laboratory; access, access control and facilities. The layout of the FCB and the requirements for these systems are described. (10 figs.)

  18. The Dependence of CNT Aerogel Synthesis on Sulfur-driven Catalyst Nucleation Processes and a Critical Catalyst Particle Mass Concentration.

    Science.gov (United States)

    Hoecker, Christian; Smail, Fiona; Pick, Martin; Weller, Lee; Boies, Adam M

    2017-11-06

    The floating catalyst chemical vapor deposition (FC-CVD) process permits macro-scale assembly of nanoscale materials, enabling continuous production of carbon nanotube (CNT) aerogels. Despite the intensive research in the field, fundamental uncertainties remain regarding how catalyst particle dynamics within the system influence the CNT aerogel formation, thus limiting effective scale-up. While aerogel formation in FC-CVD reactors requires a catalyst (typically iron, Fe) and a promotor (typically sulfur, S), their synergistic roles are not fully understood. This paper presents a paradigm shift in the understanding of the role of S in the process with new experimental studies identifying that S lowers the nucleation barrier of the catalyst nanoparticles. Furthermore, CNT aerogel formation requires a critical threshold of Fe x C y  > 160 mg/m 3 , but is surprisingly independent of the initial catalyst diameter or number concentration. The robustness of the critical catalyst mass concentration principle is proved further by producing CNTs using alternative catalyst systems; Fe nanoparticles from a plasma spark generator and cobaltocene and nickelocene precursors. This finding provides evidence that low-cost and high throughput CNT aerogel routes may be achieved by decoupled and enhanced catalyst production and control, opening up new possibilities for large-scale CNT synthesis.

  19. Non-Precious Bimetallic Catalysts for Selective Dehydrogenation of an Organic Chemical Hydride System

    KAUST Repository

    Shaikh Ali, Anaam; Jedidi, Abdesslem; Cavallo, Luigi; Takanabe, Kazuhiro

    2015-01-01

    Methylcyclohexane (MCH)-Toluene (TOL) chemical hydride cycles as a hydrogen carrier system is successful with the selective dehydrogenation reaction of MCH to TOL, which has been achieved only using precious Pt-based catalysts. Herein, we report

  20. A comparison of Rh/CeO2/SiO2 catalysts with steam reforming catalysts, dolomite and inert materials as bed materials in low throughput fluidized bed gasification systems

    International Nuclear Information System (INIS)

    Asadullah, Mohammad; Miyazawa, Tomohisa; Ito, Shin-ichi; Kunimori, Kimio; Koyama, Shuntarou; Tomishige, Keiichi

    2004-01-01

    The gasification of cedar wood in the presence of Rh/CeO 2 /SiO 2 has been conducted in the laboratory scale fluidized bed reactor using air as a gasifying agent at low temperatures (823-973 K) in order to produce high-quality fuel gas for gas turbine for power generation. The performance of the Rh/CeO 2 /SiO 2 catalyst has been compared with conventional catalysts such as commercial steam reforming catalyst G-91, dolomite and noncatalyst systems by measurements of the cold gas efficiency, tar concentration, carbon conversion to gas and gas composition. The tar concentration was completely negligible in the Rh/CeO 2 /SiO 2 -catalyzed product gas whereas it was about 30, 113, and 139 g/m 3 in G-91, dolomite and noncatalyzed product gas, respectively. Since the carbon conversion to useful gas such as CO, H 2 , and CH 4 are much higher on Rh/CeO 2 /SiO 2 catalyst than others at 873 K, the cold gas efficiency is much higher (71%) in this case than others. The hydrogen content in the product gas is much higher (>24 vol%) than the specified level (>10 vol%) for efficient combustion in the gas turbine engine. The char and coke formation is also very low on Rh/CeO 2 /SiO 2 catalyst than on the conventional catalysts. Although the catalyst surface area was slightly decreased after using the same catalyst in at least 20 experiments, the deactivation problem was not severe

  1. Application of New Electrolyte Model to Phase Transfer Catalyst (PTC) Systems

    DEFF Research Database (Denmark)

    Hyung Kim, Sun; Anantpinijwatna, Amata; Kang, Jeong Won

    2015-01-01

    Abstract Phase transfer catalyst (PTC) is used to transfer the desirable active form of an anion from the aqueous phase to organic phase where the reaction occurs. One of major challenges for process design of the PTC system is to establish a reliable thermodynamic model capable of describing pha...... in PTC systems, thereby, extending the application range of the PTC-system model. The solubility of PTC in organic solvents, which is a key factor for strategy of PTC and solvent selection, has been calculated using the e-NRTL-SAC model....

  2. Tritium processing tests for the validation of upgraded PERMCAT mechanical design

    Energy Technology Data Exchange (ETDEWEB)

    Demange, D.; Glugla, M.; Guenther, K.; Le, T. L.; Simon, K. H.; Wagner, R.; Welte, S. [Forschungszentrum Karlsruhe GmbH, Institue for Technical Physics, Tritium Laboratory Karlsruhe, P.O Box 36 40, D-76021 Karlsruhe (Germany)

    2008-07-15

    The PERMCAT process, chosen for the final clean-up stage of the Tritium Exhaust Processing system in ITER, directly combines a Pd/Ag membrane and a catalyst bed for the detritiation of gaseous mixtures containing molecular and chemically bound tritium. Upgraded PERMCAT mechanical designs have been proposed to both increase the robustness and simplify the design of the reactor. One uses a special corrugated Pd/Ag membrane able to withstand change in length of the membrane during both normal operation and in the case of off-normal events. Based on this design, an upgraded PERMCAT reactor has been produced at FZK and successfully tested at TLK with ITER relevant tritiated gaseous mixtures using the CAPER facility. (authors)

  3. Tritium processing tests for the validation of upgraded PERMCAT mechanical design

    International Nuclear Information System (INIS)

    Demange, D.; Glugla, M.; Guenther, K.; Le, T. L.; Simon, K. H.; Wagner, R.; Welte, S.

    2008-01-01

    The PERMCAT process, chosen for the final clean-up stage of the Tritium Exhaust Processing system in ITER, directly combines a Pd/Ag membrane and a catalyst bed for the detritiation of gaseous mixtures containing molecular and chemically bound tritium. Upgraded PERMCAT mechanical designs have been proposed to both increase the robustness and simplify the design of the reactor. One uses a special corrugated Pd/Ag membrane able to withstand change in length of the membrane during both normal operation and in the case of off-normal events. Based on this design, an upgraded PERMCAT reactor has been produced at FZK and successfully tested at TLK with ITER relevant tritiated gaseous mixtures using the CAPER facility. (authors)

  4. Tritium transfer process using the CRNL wetproof catalyst

    International Nuclear Information System (INIS)

    Chuang, K.T.; Holtslander, W.J.

    1980-01-01

    The recovery of tritium from heavy water in CANDU reactor systems requires the transfer of the tritium atoms from water to hydrogen molecules prior to tritium concentration by cryogenic distillation. Isotopic exchange between liquid water and hydrogen using the CRNL-developed wetproof catalyst provides an effective method for the tritium transfer process. The development of this process has required the translation of the technology from a laboratory demonstration of catalyst activity for the exchange reaction to proving and demonstration that the process will meet the practical restraints in a full-scale tritium recovery plant. This has led to a program to demonstrate acceptable performance of the catalyst at operating conditions that will provide data for design of large plants. Laboratory and pilot plant work has shown adequate catalyst lifetimes, demonstrated catalyst regeneration techniques and defined and required feedwater purification systems to ensure optimum catalyst performance. The ability of the catalyst to promote the exchange of hydrogen isotopes between water and hydrogen has been shown to be technically feasible for the tritium transfer process

  5. Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

    International Nuclear Information System (INIS)

    Amende, Max; Kaftan, Andre; Bachmann, Philipp; Brehmer, Richard; Preuster, Patrick; Koch, Marcus

    2016-01-01

    Graphical abstract: - Highlights: • We examine the regeneration of Pt-based catalysts poisoned by LOHC degradation. • A microscopic mechanism of the removal of degradation products from Pt is proposed. • Results of our UHV studies on model catalysts are transferred to real catalysis. • Oxidative regeneration of Pt/alumina is possible under mild conditions (600 K). • The degree and temperature regime of regeneration depends on the catalyst morphology. - Abstract: The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al_2O_3 model catalysts, and near-ambient pressure (NAP) measurements on real core–shell Pt/Al_2O_3 catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al_2O_3 model catalyst and core–shell pellet were only

  6. Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

    Energy Technology Data Exchange (ETDEWEB)

    Amende, Max, E-mail: max.amende@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Kaftan, Andre, E-mail: andre.kaftan@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Bachmann, Philipp, E-mail: philipp.bachmann@fau.de [Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Brehmer, Richard, E-mail: richard.brehmer@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Preuster, Patrick, E-mail: patrick.preuster@fau.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); Koch, Marcus, E-mail: marcus.koch@crt.cbi.uni-erlangen.de [Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen (Germany); and others

    2016-01-01

    Graphical abstract: - Highlights: • We examine the regeneration of Pt-based catalysts poisoned by LOHC degradation. • A microscopic mechanism of the removal of degradation products from Pt is proposed. • Results of our UHV studies on model catalysts are transferred to real catalysis. • Oxidative regeneration of Pt/alumina is possible under mild conditions (600 K). • The degree and temperature regime of regeneration depends on the catalyst morphology. - Abstract: The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al{sub 2}O{sub 3} model catalysts, and near-ambient pressure (NAP) measurements on real core–shell Pt/Al{sub 2}O{sub 3} catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al{sub 2}O{sub 3} model catalyst and

  7. Membrane reactor for water detritiation: a parametric study on operating parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mascarade, J.; Liger, K.; Troulay, M.; Perrais, C. [CEA, DEN, DTN/STPA/LIPC, Centre de Cadarache, Saint-Paul-lez-Durance (France); Joulia, X.; Meyer, X.M. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Toulouse (France); CNRS, Laboratoire de Genie Chimique, Toulouse (France)

    2015-03-15

    This paper presents the results of a parametric study done on a single stage finger-type packed-bed membrane reactor (PBMR) used for heavy water vapor de-deuteration. Parametric studies have been done on 3 operating parameters which are: the membrane temperature, the total feed flow rate and the feed composition through D{sub 2}O content variations. Thanks to mass spectrometer analysis of streams leaving the PBMR, speciation of deuterated species was achieved. Measurement of the amounts of each molecular component allowed the calculation of reaction quotient at the packed-bed outlet. While temperature variation mainly influences permeation efficiency, feed flow rate perturbation reveals dependence of conversion and permeation properties to contact time between catalyst and reacting mixture. The study shows that isotopic exchange reactions occurring on the catalyst particles surface are not thermodynamically balanced. Moreover, the variation of the heavy water content in the feed exhibits competition between permeation and conversion kinetics.

  8. SO2 oxidation catalyst model systems characterized by thermal methods

    DEFF Research Database (Denmark)

    Hatem, G; Eriksen, Kim Michael; Gaune-Escard, M

    2002-01-01

    The molten salts M2S2O7 and MHSO4, the binary molten salt Systems M2S2O7-MHSO4 and the molten salt-gas systems M2S2O7 V2O5 and M2S2O7-M2SO4 V2O5 (M = Na, K, Rb, Cs) in O-2, SO2 and At atmospheres have been investigated by thermal methods like calorimetry, Differential Enthalpic Analysis (DEA) and...... to the mechanism Of SO2 oxidation by V2O5 based industrial catalysts....

  9. The role of zeolites in the deactivation of multifunctional fischer-tropsch synthesis catalysts: the interaction between HZSM-5 and Fe-based Ft-catalysts

    Directory of Open Access Journals (Sweden)

    P. C. Zonetti

    2013-12-01

    Full Text Available In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis.

  10. The role of zeolites in the deactivation of multifunctional Fischer-Tropsch Synthesis catalysts: the interaction between HZSM-5 and Fe-based FT-catalysts

    International Nuclear Information System (INIS)

    Zonetti, P.C.; Gaspar, A.B.; Mendes, F.M.T.; Appel, L.G.; Avillez, R. R. de; Sousa-Aguiar, E.F.

    2013-01-01

    In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis. (author)

  11. The role of zeolites in the deactivation of multifunctional Fischer-Tropsch Synthesis catalysts: the interaction between HZSM-5 and Fe-based FT-catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zonetti, P.C.; Gaspar, A.B.; Mendes, F.M.T.; Appel, L.G., E-mail: lucia.appel@int.gov.br [Instituto Nacional de Tecnologia (INT/MCT), Rio de Janeiro, RJ (Brazil); Avillez, R. R. de [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil); Sousa-Aguiar, E.F. [Centro de Pesquisa Leopoldo Americo Miguez de Mello (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2013-10-15

    In order to produce gasoline directly from syngas, HZSM-5 can be added to the Fischer-Tropsch catalyst. However, this catalytic system shows an important deactivation rate. Aiming at describing this phenomenon, Fe-based catalysts and physical mixtures containing these catalysts and HZSM-5 were employed in this reaction. All these systems were characterized using the following techniques: XRD, XPS, TPR and TPD of CO. This work shows that HZSM-5 interacts with the Fe-based Fischer-Tropsch catalyst during the reduction step, decreasing the Fe concentration on the catalytic surface and thus lowering the activity of the catalytic system in the Fischer-Tropsch Synthesis. (author)

  12. Application of a mixed metal oxide catalyst to a metallic substrate

    Science.gov (United States)

    Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

    2009-01-01

    A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

  13. New catalysts for exhaust gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Haerkoenen, M [Kemira Metalkat Oy, Oulu (Finland)

    1997-12-31

    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.)

  14. 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.)

  15. Extended Catalyst Longevity Via Supercritical Isobutane Regeneration of a Partially Deactivated USY Alkylation Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; David N. Thompson; Kyle C. Burch; David J. Zalewski

    2005-05-01

    Off-line, in situ activity recovery of a partially deactivated USY zeolite catalyst used for isobutane/butene alkylation was examined in a continuous-flow reaction system employing supercritical isobutane. Catalyst samples were deactivated in a controlled manner by running them to either to a fixed butene conversion level of 95% or a fixed time on stream of three hours, and then exposing the catalyst to supercritical isobutane to restore activity. Activity recovery was determined by comparing alkylation activity before and after the regeneration step. Both single and multiple regenerations were performed. Use of a 95% butene conversion level criterion to terminate the reaction step afforded 86% activity recovery for a single regeneration and provided nine sequential reaction steps for the multiple regeneration studies. Employing a fixed 3 h time on stream criterion resulted in nearly complete activity recovery for a single regeneration, and 24 reaction steps were demonstrated in sequence for the multiple regeneration process, producing only minor product yield declines per step. This resulted in a 12-fold increase in catalyst longevity versus unregenerated catalyst.

  16. Selective catalytic reduction system and process for treating NOx emissions using a zinc or titanium promoted palladium-zirconium catalyst

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    2011-08-02

    A process and system (18) for reducing NO.sub.x in a gas using hydrogen as a reducing agent is provided. The process comprises contacting the gas stream (29) with a catalyst system (38) comprising sulfated zirconia washcoat particles (41), palladium, a pre-sulfated zirconia binder (44), and a promoter (45) comprising at least one of titanium, zinc, or a mixture thereof. The presence of zinc or titanium increases the resistance of the catalyst system to a sulfur and water-containing gas stream.

  17. Studies on recycling and utilization of spent catalysts. Preparation of active hydrodemetallization catalyst compositions from spent residue hydroprocessing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, Meena; Stanislaus, Antony [Petroleum Refining Department, Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, Safat (Kuwait)

    2007-02-15

    Spent catalysts form a major source of solid wastes in the petroleum refining industries. Due to environmental concerns, increasing emphasis has been placed on the development of recycling processes for the waste catalyst materials as much as possible. In the present study the potential reuse of spent catalysts in the preparation of active new catalysts for residual oil hydrotreating was examined. A series of catalysts were prepared by mixing and extruding spent residue hydroprocessing catalysts that contained C, V, Mo, Ni and Al{sub 2}O{sub 3} with boehmite in different proportions. All prepared catalysts were characterized by chemical analysis and by surface area, pore volume, pore size and crushing strength measurements. The hydrodesulfurization (HDS) and hydrodemetallization (HDM) activities of the catalysts were evaluated by testing in a high pressure fixed-bed microreactor unit using Kuwait atmospheric residue as feed. A commercial HDM catalyst was also tested under similar operating conditions and their HDS and HDM activities were compared with that of the prepared catalysts. The results revealed that catalyst prepared with addition of up to 40 wt% spent catalyst to boehmite had fairly high surface area and pore volume together with large pores. The catalyst prepared by mixing and extruding about 40 wt% spent catalyst with boehmite was relatively more active for promoting HDM and HDS reactions than a reference commercial HDM catalyst. The formation of some kind of new active sites from the metals (V, Mo and Ni) present in the spent catalyst is suggested to be responsible for the high HDM activity of the prepared catalyst. (author)

  18. Tethered catalysts for the hydration of carbon dioxide

    Science.gov (United States)

    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.

  19. Tritium effluent removal system

    International Nuclear Information System (INIS)

    Lamberger, P.H.; Gibbs, G.E.

    1978-01-01

    An air detritiation system has been developed and is in routine use for removing tritium and tritiated compounds from glovebox effluent streams before they are released to the atmosphere. The system is also used, in combination with temporary enclosures, to contain and decontaminate airborne releases resulting from the opening of tritium containment systems during maintenance and repair operations. This detritiation system, which services all the tritium handling areas at Mound Facility, has played an important role in reducing effluents and maintaining them at 2 percent of the level of 8 y ago. The system has a capacity of 1.7 m 3 /min and has operated around the clock for several years. A refrigerated in-line filtration system removes water, mercury, or pump oil and other organics from gaseous waste streams. The filtered waste stream is then heated and passed through two different types of oxidizing beds; the resulting tritiated water is collected on molecular sieve dryer beds. Liquids obtained from regenerating the dryers and from the refrigerated filtration system are collected and transferred to a waste solidification and packaging station. Component redundancy and by-pass capabilities ensure uninterrupted system operation during maintenance. When processing capacity is exceeded, an evacuated storage tank of 45 m 3 is automatically opened to the inlet side of the system. The gaseous effluent from the system is monitored for tritium content and recycled or released directly to the stack. The average release is less than 1 Ci/day. The tritium effluent can be reduced by isotopically swamping the tritium; this is accomplished by adding hydrogen prior to the oxidizer beds, or by adding water to the stream between the two final dryer beds

  20. Experimental Investigation in Order to Determine Catalytic Package Performances in Case of Tritium Transfer from Water to Gas

    International Nuclear Information System (INIS)

    Bornea, Anisia; Peculea, M.; Zamfirache, M.; Varlam, Carmen

    2005-01-01

    The processes for hydrogen isotope's separation are very important for nuclear technology. One of the most important processes for tritium separation, is the catalyst isotope exchange water-hydrogen.Our catalytic package consists of Romanian patented catalysts with platinum on charcoal and polytetrafluoretylene (Pt/C/PTFE) and the ordered Romanian patented package B7 type. The catalytic package was tested in an isotope exchange facility for water detritiation at the Experimental Pilot Plant from ICIT Rm.Valcea.In a column of isotope exchange tritium is transferred from liquid phase (tritiated heavy water) in gaseous phase (hydrogen). In the experimental set-up, which was used, the column of catalytic isotope exchange is filled with successive layers of catalyst and ordered package. The catalyst consists of 95.5 wt.% of PTFE, 4.1 wt. % of carbon and 0.40 wt. % of platinum and was of Raschig rings 10 x 10 x 2 mm. The ordered package was B7 type consists of wire mesh phosphor bronze 4 x 1 wire and the mesh dimension is 0.18 x 0.48 mm.We analyzed the transfer phenomena of tritium from liquid to gaseous phase, in this system.The mass transfer coefficient which characterized the isotopic exchange on the package, were determined as function of experimental parameters

  1. A feasible process for furfural production from the pre-hydrolysis liquor of corncob via biochar catalysts in a new biphasic system.

    Science.gov (United States)

    Deng, Aojie; Lin, Qixuan; Yan, Yuhuan; Li, Huiling; Ren, Junli; Liu, Chuanfu; Sun, Runcang

    2016-09-01

    A feasible approach was developed to produce furfural from the pre-hydrolysis liquor of corncob via biochar catalysts as the solid acid catalyst in a new biphasic system with dichloromethane (DCM) as the organic phase and the concentrated pre-hydrolysis liquor (CPHL) containing NaCl as the aqueous phase. The biochar catalyst possessing many acidity groups (SO3H, COOH and phenolic OH groups) was prepared by the carbonization and sulfonation process of the corncob hydrolyzed residue. The influence of the catalytic condition on furfural yield and selectivity was comparatively studied. It was found that 81.14% furfural yield and 83.0% furfural selectivity were obtained from CPHL containing 5wt% xylose using this biochar catalyst in the CPHL-NaCl/DCM biphasic system at 170°C for 60min. In addition, with the regeneration process, this catalyst displayed the high performance and excellent recyclability. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    KAUST Repository

    Renard, Laetitia; El Eter, Mohamad; Caps, Valerie; Basset, Jean-Marie

    2014-01-01

    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.

  3. 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.

  4. Self-regenerative function of the intelligent automotive catalyst

    International Nuclear Information System (INIS)

    Tanaka, Hirohisa; Nishihata, Yasuo

    2007-01-01

    Intelligent catalyst, in which noble metals are used as an active part of automotive catalyst, has been considered for keeping up their sufficient activity. The noble metals have a function of cleaning up the exhaust gas as well as that of self-regeneration. In 2002, a Pd system has been put to practical use, and continuously Rh and Pt systems have been commercialized. Now the catalyst has been used in more than three million vehicles. In this report, the atomic level mechanism of the catalyst and its self-regeneration function getting from analyses using synchrotron radiation are introduced. By the analysis using the Spring-8, the mechanism of keeping the active state of the Pd Perovskite Oxide without degradation was identified. The DXAFS (Dispersive X-ray Absorption Fine Structure) analysis in the ESRF (European Synchrotron Radiation Facility) made clear the self-regeneration mechanism of the Pd Perovskite Oxide. This knowledge could lead to the practical development of the Rh and Pt systems. The catalyst technology is counted on balancing resources of the noble metal and environmental sustainability. (A.H.)

  5. Surface chemistry and catalytic properties of VOX/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    International Nuclear Information System (INIS)

    González, J.; Chen, L.F.; Wang, J.A.; Manríquez, Ma.; Limas, R.; Schachat, P.; Navarrete, J.; Contreras, J.L.

    2016-01-01

    Highlights: • Oxidative desulfurization of model diesel was tested in a biphasic system. • ODS activity was proportional to the V 5+ /(V 4+ + V 5+ ) values of the catalysts. • Lewis acidity was related to vanadium content and catalytic activity. • 99.9% DBT was oxidized using 25%V 2 O 5 /Ti-MCM-41 at 60 °C within 60 min. - Abstract: A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H 2 O 2 as oxidant. ODS activity was found to be proportional to the V 5+ /(V 4+ + V 5+ ) values of the catalysts, indicating that the surface vanadium pentoxide (V 2 O 5 ) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V 2 O 5 ) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V 2 O 5 /Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  6. Immobilization of molecular catalysts in supported ionic liquid phases.

    Science.gov (United States)

    Van Doorslaer, Charlie; Wahlen, Joos; Mertens, Pascal; Binnemans, Koen; De Vos, Dirk

    2010-09-28

    In a supported ionic liquid phase (SILP) catalyst system, an ionic liquid (IL) film is immobilized on a high-surface area porous solid and a homogeneous catalyst is dissolved in this supported IL layer, thereby combining the attractive features of homogeneous catalysts with the benefits of heterogeneous catalysts. In this review reliable strategies for the immobilization of molecular catalysts in SILPs are surveyed. In the first part, general aspects concerning the application of SILP catalysts are presented, focusing on the type of catalyst, support, ionic liquid and reaction conditions. Secondly, organic reactions in which SILP technology is applied to improve the performance of homogeneous transition-metal catalysts are presented: hydroformylation, metathesis reactions, carbonylation, hydrogenation, hydroamination, coupling reactions and asymmetric reactions.

  7. 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....

  8. 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.

  9. Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

    KAUST Repository

    Widger, Peter C. B.; Ahmed, Syud M.; Coates, Geoffrey W.

    2011-01-01

    Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

  10. Exploration of Cocatalyst Effects on a Bimetallic Cobalt Catalyst System: Enhanced Activity and Enantioselectivity in Epoxide Polymerization

    KAUST Repository

    Widger, Peter C. B.

    2011-07-26

    Organic ionic compounds were synthesized and investigated as cocatalysts with a bimetallic cobalt complex for enantioselective epoxide polymerization. The identities of both the cation and the anion were systematically varied, and the subsequent reactivity was studied. The nature of the ionic cocatalyst dramatically impacted the rate and enantioselectivity of the catalyst system. The ionic cocatalyst [P(N=P(N(CH2)4)3) 4 +][tBuCO2 -] in combination with a bimetallic cobalt complex produced a catalyst system that exhibited the greatest activity and selectivity for a variety of monosubstituted epoxides. © 2011 American Chemical Society.

  11. SU-F-J-20: Commissioning and Acceptance Testing of the C-Rad CatalystHD Surface Imaging System

    International Nuclear Information System (INIS)

    Stanley, D; Rasmussen, K; Kirby, N; Papanikolaou, N; Gutierrez, A

    2016-01-01

    Introduction: With the increasing use of surface-based, nonionizing image-guided radiotherapy (IGRT) systems, a comprehensive set of clinical acceptance and commissioning procedures are needed to ensure correct functionality and proper clinical integration. Although TG-147 provides a specific set of parameters, measurement methodologies have yet to be described. The aim of this study was to provide a comprehensive overview of the commissioning and acceptance analysis performed for the C-Rad CatalystHD imaging system. Methods and Materials: Methodology for the commissioning and acceptance of the C-Rad CatalystHD imaging system was developed using commercially available clinical equipment. Following TG-147 guidelines, the following tests were performed: integration of peripheral equipment, system drift, static spatial reproducibility and localization accuracy, static end-to-end analysis, static rotational accuracy, dynamic spatial accuracy, dynamic temporal accuracy, dynamic radiation delivery and a comprehensive end-to-end analysis. Results: The field of view (FOV) of the CatalystHD was 105×109×83 cm3 in the lateral, longitudinal and vertical directions. For thermal equilibrium and system drift, a thermal drift of 1.0mm was noted. A 45 min warmup time is recommended if the system has been shut off an extended period of time (>24 hours) before the QA procedure to eliminate any thermal drift. Spatial reproducibility was found to be 0.05±0.03 mm using a rigid phantom. For the static localization accuracy, system agreement with couch shifts was within 0.1±0.1 mm and positioning agreement with kV-CBCT was 0.16±0.10 mm. For static rotational accuracy, system agreement with a high precision rotational stage (0.01 deg precision) was within 0.10±0.07 deg. Dynamic spatial and temporal localization accuracy was found to be within 0.2±0.1 mm. Conclusion: A comprehensive commissioning and acceptance study was performed using commercially available phantoms and in

  12. Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

    Science.gov (United States)

    Kilvington, Simon; Winterton, Lynn

    2017-11-01

    Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

  13. NOx removal from the flue gas of oil-fired boiler using a multistage plasma-catalyst hybrid system

    International Nuclear Information System (INIS)

    Park, Sung Youl; Deshwal, Bal Raj; Moon, Seung Hyun

    2008-01-01

    The study on removal of NO x from the flue gas of oil-fired boiler has been carried out using non-thermal plasma cum catalyst hybrid reactor at 150 C. Propylene (C 3 H 6 ) was used as a reducing agent. A multistage plasma-catalyst hybrid reactor was newly designed and successfully operated to clean up the flue gas stream having a flow rate of 30 Nm 3 /h. TiO 2 and Pd/ZrO 2 wash-coated on cordierite honeycomb were used as catalysts in the present study. Though the plasma-catalyst hybrid reactor with TiO 2 showed good activity on the removal of NO yet it removed only 50-60% of NO x because a significant portion of NO oxidized to NO 2 . On the contrary, the plasma-catalyst hybrid reactor with Pd/ZrO 2 removed about 50% of inlet NO with a negligible amount of NO oxidation into NO 2 . The plasma/dual-catalysts hybrid system (front two units of plasma-Pd/ZrO 2 + rear two units of plasma/TiO 2 ) proved to be very promising in NO x removal in the presence of C 3 H 6 . DeNO x efficiency of about 74% has been achieved at a space velocity of 3300/h at 150 C. (author)

  14. Electrolyser for CECE process

    International Nuclear Information System (INIS)

    Lee, Min Soo; Chung, Hong Suk; Paek, Seung Woo; Kim, Kwang Rag; Yim, Sung Paal; Ahn, Do Hee

    2005-01-01

    A combined electrolysis catalytic exchange (CECE) facility employing a liquid phase catalytic exchange (LPCE) column for water detritiation is currently being studied at the tritium treatment laboratory in KAERI, which is also adopted for water detritiation in JET, ITER, and TLK (tritium laboratory Karlsruhe). The CECE facility is needed for process performance studies, to support the design of the Water Detritiation System for the nuclear industry, such as nuclear reactor operations and a radioisotope production, and medical research. The design and commissioning of this demonstration scale facility to investigate the achievable tritium decontamination factor are ongoing. A simple schematic of the CECE process is shown in Figure 1. The key elements of the facility are an electrolyser for conversion of tritiated water to gaseous hydrogen, and a LPCE column where this hydrogen is detritiated via isotopic exchange with liquid water

  15. Advances in propane ammoxidation catalyst technology

    Energy Technology Data Exchange (ETDEWEB)

    Prada Silvy, R.; Grange, P. [Unite de Catalyse et Chimie des Materiaux Divises, Univ. Cathologique de Louvain, Louvain-la-Neuve (Belgium)

    2003-09-01

    Comparison of the catalytic performance of different propane ammoxidation catalyst systems from the patent literature is established in order to identify the most promising formulation towards process commercialization scale. Vanadium aluminum oxynitride material shows the highest acrylonitrile production level per hour and per amount of catalyst with respect to conventional vanadium-molybdate and vanadium- antimonate mixed oxide propane ammoxidation systems. Acrylonitrile, hydrogen cyanide and acetonitrile production from propane ammoxidation is the key factor for obtaining competitive advantages over current propylene technology. (orig.)

  16. Ship-in-a-bottle catalysts

    Science.gov (United States)

    Haw, James F.; Song, Weiguo

    2006-07-18

    In accordance with the present invention there is provided a novel catalyst system in which the catalytic structure is tailormade at the nanometer scale using the invention's novel ship-in-a-bottle synthesis techniques. The invention describes modified forms of solid catalysts for use in heterogeneous catalysis that have a microporous structure defined by nanocages. Examples include zeolites, SAPOs, and analogous materials that have the controlled pore dimensions and hydrothermal stability required for many industrial processes. The invention provides for modification of these catalysts using reagents that are small enough to pass through the windows used to access the cages. The small reagents are then reacted to form larger molecules in the cages.

  17. Nano-catalysts: Bridging the gap between homogeneous and heterogeneous catalysis

    Science.gov (United States)

    Functionalized nanoparticles have emerged as sustainable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. We envisioned a catalyst system, which can bridge the homogenous and heterogeneous system. Postsynthetic surface modifica...

  18. An introduction to catalyst

    International Nuclear Information System (INIS)

    Jeon, Hak Je

    1988-11-01

    This book explains basic conception of catalyst such as definition, velocity of chemical reaction and velocity of catalyst reaction, absorption with absorption energy and chemical absorption, pore structure with the role of pore and measurement of pore structure, catalyst activity on solid structure, electrical property on catalyst activity, choice and design of catalyst, catalytic reaction with reaction velocity and chemical equilibrium and reaction velocity model, measurement of reaction velocity and material analysis, catalyst for mixed compound, catalyst for solid acid and catalyst for supported metal.

  19. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

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

    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...... 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...

  20. Selective catalytic reduction system and process for treating NOx emissions using a palladium and rhodium or ruthenium catalyst

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    2011-07-12

    A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H.sub.2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.

  1. Boron-containing catalysts for dry reforming of methane to synthesis gas

    KAUST Repository

    Takanabe, Kazuhiro

    2018-01-04

    The present invention uses a cobalt catalyst for carbon dioxide reforming of lower alkanes to synthesis gas having a cobalt catalyst on an oxide support where the supported cobalt catalyst has been modified with a boron precursor. The boron-treated cobalt catalyst systems as described herein show significant increases in the conversion of CH4 and CO2 during the dry reforming of methane (DRM) reaction as compared to traditional catalysts. Described herein are supported catalysts and methods of using the catalysts for the dry reforming of methane to synthesis gas, with the supported catalysts in the present invention include a boron-treated cobalt catalyst disposed on an oxide support. Also described herein are processes for preparing the supported catalysts.

  2. Effect of Iminodiacetic Acid-Modified Nieuwland Catalyst on the Acetylene Dimerization Reaction

    Directory of Open Access Journals (Sweden)

    Yanhe You

    2017-12-01

    Full Text Available The iminodiacetic acid-modified Nieuwland catalyst not only improves the conversion of acetylene but also increases the selectivity of monovinylacetylene (MVA. A catalyst system containing 4.5% iminodiacetic acid exhibited excellent performance, and the yield of MVA was maintained at 32% after 24 h, producing an increase in the yield by 12% relative to the Nieuwland catalyst system. Based on a variety of characterization methods analysis of the crystal precipitated from the catalyst solution, it can be inferred that the outstanding performance and lifetime of the catalyst system was due to the presence of iminodiacetic acid, which increases the electron density of Cu+ and adjusts the acidity of the catalytic solution.

  3. Continuous flow hydrogenation using polysilane-supported palladium/alumina hybrid catalysts

    Directory of Open Access Journals (Sweden)

    Shū Kobayashi

    2011-05-01

    Full Text Available Continuous flow systems for hydrogenation using polysilane-supported palladium/alumina (Pd/(PSi–Al2O3 hybrid catalysts were developed. Our original Pd/(PSi–Al2O3 catalysts were used successfully in these systems and the hydrogenation of unsaturated C–C bonds and a nitro group, deprotection of a carbobenzyloxy (Cbz group, and a dehalogenation reaction proceeded smoothly. The catalyst retained high activity for at least 8 h under neat conditions.

  4. Productions of sunflower oil biodiesel and used cooking oil through heterogeneous catalysts compared to conventional homogeneous catalysts

    International Nuclear Information System (INIS)

    Gutiérrez-Zapata, C A; Collazos, C A; Acuña, H E Castellanos; Fernandez, C P; Martínez, D Blanco; Cuervo, J A

    2017-01-01

    This document compares homogeneous and heterogeneous catalysts used by production of biodiesel of sunflower oil and cooking oil used in frying. For this, NaOH was used as a catalyst homogeneous, and K 2 CO 3 and Na 2 CO 3 supported in gamma-alumina (K 2 CO 3 /γ Al 2 O 3 y Na 2 CO 3 /γ-Al 2 O 3 ) were synthesized as heterogeneous catalysts, which were characterized by X-ray diffraction. The transesterification tests were carried out for the sunflower oil and used cooking oil, in a reflux system, to different molar relations methanol/oil, depending on the type of oil and characterization of the same. The reflux system is performed at a temperature of 55-60°C for one hour. Finally, biofuel was characterized and the yield of the reaction was calculated. (paper)

  5. Productions of sunflower oil biodiesel and used cooking oil through heterogeneous catalysts compared to conventional homogeneous catalysts

    Science.gov (United States)

    Gutiérrez-Zapata, C. A.; Blanco Martínez, D.; Collazos, C. A.; Castellanos Acuña, H. E.; Cuervo, J. A.; Fernandez, C. P.

    2017-01-01

    This document compares homogeneous and heterogeneous catalysts used by production of biodiesel of sunflower oil and cooking oil used in frying. For this, NaOH was used as a catalyst homogeneous, and K2CO3 and Na2CO3 supported in gamma-alumina (K2CO3/γ Al2O3 y Na2CO3 /γ-Al2O3) were synthesized as heterogeneous catalysts, which were characterized by X-ray diffraction. The transesterification tests were carried out for the sunflower oil and used cooking oil, in a reflux system, to different molar relations methanol/oil, depending on the type of oil and characterization of the same. The reflux system is performed at a temperature of 55-60°C for one hour. Finally, biofuel was characterized and the yield of the reaction was calculated.

  6. 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.

  7. Catalysts Efficiency Evaluation by using CC Analysis Test

    Directory of Open Access Journals (Sweden)

    Arina Negoitescu

    2011-10-01

    Full Text Available The study emphasizes the necessity of the catalysts efficiency testing. Diagnosis systems using lambda probes are based on the capacity of the catalyst oxygen storage. Comparing the lambda probe signals upstream and downstream of catalyst provides an indication on catalyst activity, although the correlation between oxygen storage capacity and catalyst efficiency is still difficult. Diagnosis for the 1.4 Renault Clio Symbol was accomplished in the Road Vehicles Lab at the Politehnica University of Timisoara using AVL Dicom 4000. The tests showed that the engine worked with lean mixture being necessary a fuel mixture correction calculated by the control unit ECU. A compensation of 0.14 % vol is required for the engine correct operation and emissions integration within permissible limits

  8. New sulfide catalysts for the hydroliquefaction of coal

    NARCIS (Netherlands)

    Vissers, J.P.R.; Oers, van E.M.; Beer, de V.H.J.; Prins, R.

    1987-01-01

    Possibilities for the preparation of new metal sulfide catalyst systems based on carbon carriers having favourable textural and surface properties have been explored, and attention has been given to the characterization (structure) and evaluation (hydrosulfurization activity) of these catalysts. Two

  9. Surface chemistry and catalytic properties of VOX/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    Science.gov (United States)

    González, J.; Chen, L. F.; Wang, J. A.; Manríquez, Ma.; Limas, R.; Schachat, P.; Navarrete, J.; Contreras, J. L.

    2016-08-01

    A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H2O2 as oxidant. ODS activity was found to be proportional to the V5+/(V4+ + V5+) values of the catalysts, indicating that the surface vanadium pentoxide (V2O5) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V2O5) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V2O5/Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  10. 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

  11. Photocatalytic oxidation of organic compounds in a hybrid system composed of a molecular catalyst and visible light-absorbing semiconductor.

    Science.gov (United States)

    Zhou, Xu; Li, Fei; Li, Xiaona; Li, Hua; Wang, Yong; Sun, Licheng

    2015-01-14

    Photocatalytic oxidation of organic compounds proceeded efficiently in a hybrid system with ruthenium aqua complexes as catalysts, BiVO4 as a light absorber, [Co(NH3)5Cl](2+) as a sacrificial electron acceptor and water as an oxygen source. The photogenerated holes in the semiconductor are used to oxidize molecular catalysts into the high-valent Ru(IV)=O intermediates for 2e(-) oxidation.

  12. Novel reaction engineering concepts for catalyst immobilisation in hydroformylation

    Energy Technology Data Exchange (ETDEWEB)

    Cole-Hamilton, D.J.; Desset, S.L.; Muldoon, M.J. [St. Andrews Univ. (United Kingdom). EaStChem, School of Chemistry; Hintermair, U. [St. Andrews Univ. (United Kingdom). EaStChem, School of Chemistry]|[CNRS, Lyon (France). Laboratoire de Chimie Organometallique de Surface; Santini, C.C. [CNRS, Lyon (France). Laboratoire de Chimie Organometallique de Surface

    2006-07-01

    Various methods for the separation of the aldehyde products from the catalyst and any solvent during or after hydroformylation reactions of long chain alkenes are reviewed. The catalyst can be immobilized on a soluble or insoluble support or in a phase that does not mix with the product phase under the separation conditions. Aqueous, fluorous, and ionic liquid biphasic systems as well as systems involving scCO{sub 2} sometimes in conjunction with one or other of the types of solvents listed above. Hybrid systems in which a liquid phase containing the catalyst is supported on a microporous solid support are also discussed. The advantages and disadvantages of the various systems are considered and new results concerning the addition of [1-octyl-3-methylimidazolium]Br to aqueous biphasic systems and the use of supercritical fluids to transport substrates over supported ionic liquid phases are presented. Both of these new approaches give high reaction rates, which for the supported ionic liquid phase catalysts can be maintained for at least 40 h of continuous flow operation. For the aqueous biphasic systems, leaching is low and phase separation is fast. (orig.)

  13. 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

  14. Multi-purpose hydrogen isotopes separation plant design

    Energy Technology Data Exchange (ETDEWEB)

    Boniface, H.A.; Gnanapragasam, N.V.; Ryland, D.K.; Suppiah, S.; Castillo, I. [Atomic Energy of Canada Limited - AECL, Chalk River, ON (Canada)

    2015-03-15

    There is a potential interest at AECL's Chalk River Laboratories to remove tritium from moderately tritiated light water and to reclaim tritiated, downgraded heavy water. With only a few limitations, a single CECE (Combined Electrolysis and Catalytic Exchange) process configuration can be designed to remove tritium from heavy water or light water and upgrade heavy water. Such a design would have some restrictions on the nature of the feed-stock and tritium product, but could produce essentially tritium-free light or heavy water that is chemically pure. The extracted tritium is produced as a small quantity of tritiated heavy water. The overall plant capacity is fixed by the total amount of electrolysis and volume of catalyst. In this proposal, with 60 kA of electrolysis a throughput of 15 kg*h{sup -1} light water for detritiation, about 4 kg*h{sup -1} of heavy water for detritiation and about 27 kg*h{sup -1} of 98% heavy water for upgrading can be processed. Such a plant requires about 1,000 liters of AECL isotope exchange catalyst. The general design features and details of this multi-purpose CECE process are described in this paper, based on some practical choices of design criteria. In addition, we outline the small differences that must be accommodated and some compromises that must be made to make the plant capable of such flexible operation. (authors)

  15. Surface chemistry and catalytic properties of VO{sub X}/Ti-MCM-41 catalysts for dibenzothiophene oxidation in a biphasic system

    Energy Technology Data Exchange (ETDEWEB)

    González, J. [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Chen, L.F., E-mail: lchen@ipn.mx [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Wang, J.A.; Manríquez, Ma.; Limas, R. [ESIQIE, Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional s/n, 07738 Col. Zacatenco, Mexico City (Mexico); Schachat, P.; Navarrete, J. [Dirección de Investigación, Instituto Mexicano del Petróleo, Eje Lázaro Cárdenas 152, 07730 México D.F. (Mexico); Contreras, J.L. [Laboratorio de Catálisis y Polímeros, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-A, Av. San Pablo No. 180, 02200 México D.F. (Mexico)

    2016-08-30

    Highlights: • Oxidative desulfurization of model diesel was tested in a biphasic system. • ODS activity was proportional to the V{sup 5+}/(V{sup 4+} + V{sup 5+}) values of the catalysts. • Lewis acidity was related to vanadium content and catalytic activity. • 99.9% DBT was oxidized using 25%V{sub 2}O{sub 5}/Ti-MCM-41 at 60 °C within 60 min. - Abstract: A series of vanadium oxide supported on Ti-MCM-41 catalysts was synthesized via the incipient impregnation method by varying the vanadia loading from 5 wt% to 10, 15, 20 and 25 wt%. These catalysts were characterized by a variety of advanced techniques for investigating their crystalline structure, textural properties, and surface chemistry information including surface acidity, reducibility, vanadium oxidation states, and morphological features. The catalytic activities of the catalysts were evaluated in a biphasic reaction system for oxidative desulfurization (ODS) of a model diesel containing 300 ppm of dibenzothiophene (DBT) where acetonitrile was used as extraction solvent and H{sub 2}O{sub 2} as oxidant. ODS activity was found to be proportional to the V{sup 5+}/(V{sup 4+} + V{sup 5+}) values of the catalysts, indicating that the surface vanadium pentoxide (V{sub 2}O{sub 5}) was the active phase. Reaction temperature would influence significantly the ODS efficiency; high temperature, i.e., 80 °C, would lead to low ODS reaction due to the partial decomposition of oxidant. All the catalysts contained both Lewis and Brønsted acid sites but the former was predominant. The catalysts with low vanadia loading (5 or 10 wt%V{sub 2}O{sub 5}) had many Lewis acid sites and could strongly adsorb DBT molecule via the electron donation/acceptance action which resulted in an inhibition for the reaction of DBT with the surface peroxometallic species. The catalyst with high vanadia loading (25wt%V{sub 2}O{sub 5}/Ti-MCM-41) showed the highest catalytic activity and could remove 99.9% of DBT at 60 °C within 60 min.

  16. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    Science.gov (United States)

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  17. Selection of catalysts and reactors for hydroprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. [Imaf Group, Ottawa, ON (Canada)

    1998-07-13

    The performance of hydroprocessing units can be influenced by the selection of the catalysts and the type of reactor to suit a particular feed. The catalysts and reactors selected for light feeds differ markedly from those selected for heavy feeds. Fixed-bed reactors have been traditionally used for light feeds. High asphaltene and high metal content feeds are successfully processed using moving-bed and/or ebullated bed reactors. Multi-reactor systems consisting of moving-bed and/or ebullated bed reactors in series with fixed-bed reactors can be used to process difficult feeds. For heavy feeds, the physical properties (e.g. porosity), shape and size of the catalyst particles become crucial parameters. Pretreatment of catalysts by presulfiding improves the performance of the units.

  18. Direct transformation of xylan-type hemicelluloses to furfural via SnCl₄ catalysts in aqueous and biphasic systems.

    Science.gov (United States)

    Wang, Wenju; Ren, Junli; Li, Huiling; Deng, Aojie; Sun, Runcang

    2015-05-01

    Direct catalytic transformation of xylan-type hemicelluloses to furfural in the aqueous system and the biphasic system were comparatively investigated under mild conditions. Screening of several promising chlorides for conversion of beech xylan in the aqueous system revealed the Lewis acid SnCl4 was the most effective catalyst. Comparing to the single aqueous system, the bio-based 2-methyltetrahydrofuran (2-MTHF)/H2O biphasic system was more conducive to the synthesis of furfural, in which the highest furfural yield of 78.1% was achieved by using SnCl4 as catalysts under the optimized reaction conditions (150°C, 120 min). Additionally, the influences of xylan-type hemicelluloses with different chemical and structural features from beech, corncob and bagasse on the furfural production were studied. It was found that furfural yield to some extent was determined by the xylose content in hemicelluloses and also had relationships with the molecular weight of hemicelluloses and the degree of crystallization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Advanced cathode materials for polymer electrolyte fuel cells based on pt/ metal oxides: from model electrodes to catalyst systems.

    Science.gov (United States)

    Fabbri, Emiliana; Pătru, Alexandra; Rabis, Annett; Kötz, Rüdiger; Schmidt, Thomas J

    2014-01-01

    The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials for the next generation PEFC cathodes. In the present work a multilevel approach has been adopted to investigate the kinetics and the activity of Pt nanoparticles supported on SnO2-based metal oxides. Particularly, model electrodes made of SnO2 thin films supporting Pt nanoparticles, and porous catalyst systems made of Pt nanoparticles supported on Sb-doped SnO2 high surface area powders have been investigated. The present results indicate that SnO2-based supports do not modify the oxygen reduction reaction mechanism on the Pt nanoparticle surface, but rather lead to catalysts with enhanced specific activity compared to Pt/carbon systems. Different reasons for the enhancement in the specific activity are considered and discussed.

  20. Co-Production of Electricity and Hydrogen Using a Novel Iron-based Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hilaly, Ahmad; Georgas, Adam; Leboreiro, Jose; Arora, Salil; Head, Megann; Trembly, Jason; Turk, Brian; Gupta, Raghubir

    2011-09-30

    The primary objective of this project was to develop a hydrogen production technology for gasification applications based on a circulating fluid-bed reactor and an attrition resistant iron catalyst. The work towards achieving this objective consisted of three key activities: Development of an iron-based catalyst suitable for a circulating fluid-bed reactor; Design, construction, and operation of a bench-scale circulating fluid-bed reactor system for hydrogen production; Techno-economic analysis of the steam-iron and the pressure swing adsorption hydrogen production processes. This report describes the work completed in each of these activities during this project. The catalyst development and testing program prepared and iron-based catalysts using different support and promoters to identify catalysts that had sufficient activity for cyclic reduction with syngas and steam oxidation and attrition resistance to enable use in a circulating fluid-bed reactor system. The best performing catalyst from this catalyst development program was produced by a commercial catalyst toll manufacturer to support the bench-scale testing activities. The reactor testing systems used during material development evaluated catalysts in a single fluid-bed reactor by cycling between reduction with syngas and oxidation with steam. The prototype SIP reactor system (PSRS) consisted of two circulating fluid-bed reactors with the iron catalyst being transferred between the two reactors. This design enabled demonstration of the technical feasibility of the combination of the circulating fluid-bed reactor system and the iron-based catalyst for commercial hydrogen production. The specific activities associated with this bench-scale circulating fluid-bed reactor systems that were completed in this project included design, construction, commissioning, and operation. The experimental portion of this project focused on technical demonstration of the performance of an iron-based catalyst and a

  1. System and method for controlling ammonia levels in a selective catalytic reduction catalyst using a nitrogen oxide sensor

    Science.gov (United States)

    None

    2017-07-25

    A system according to the principles of the present disclosure includes an air/fuel ratio determination module and an emission level determination module. The air/fuel ratio determination module determines an air/fuel ratio based on input from an air/fuel ratio sensor positioned downstream from a three-way catalyst that is positioned upstream from a selective catalytic reduction (SCR) catalyst. The emission level determination module selects one of a predetermined value and an input based on the air/fuel ratio. The input is received from a nitrogen oxide sensor positioned downstream from the three-way catalyst. The emission level determination module determines an ammonia level based on the one of the predetermined value and the input received from the nitrogen oxide sensor.

  2. Mobis HRH process residue hydroconversion using a recoverable nano-catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Romocki, S.; Rhodey, G. [Mobis Energy Inc., Calgary, AB (Canada)

    2009-07-01

    This presentation described a newly developed pseudo-homogeneous catalyst (PHC) for hydroconversion of heavy hydrocarbon feeds with high levels of sulphur, nitrogen, resins, asphaltenes and metals. An active catalyst is formed in the reaction system, consisting of particles that are 2-9 nm in size and whose properties resemble those of a colloid solution at both room and reaction temperature. Residue processing with this pseudo-homogeneous catalyst system results in better cracking and hydrogenation at lower process severity. The PHC system in heavy residue hydroconversion (HRH) process achieves up to 95 per cent residue conversion at pressures below 7.3 MPa, reaction temperatures between 400 to 460 degrees C, and with feed space velocity between 1 to 2 per hour, thus rendering the PHC catalyst system suitable for deep conversion of hydrocarbon residues. As much as 95 per cent of the catalyst can be recovered and regenerated within the process. Pilot plants are in operation for the hydroconversion of Athabasca vacuum bottoms using this technology. The use of the HRH process in oilsands and refinery operations were discussed along with comparative yields and economics. tabs., figs.

  3. High-throughput heterogeneous catalyst research

    Science.gov (United States)

    Turner, Howard W.; Volpe, Anthony F., Jr.; Weinberg, W. H.

    2009-06-01

    With the discovery of abundant and low cost crude oil in the early 1900's came the need to create efficient conversion processes to produce low cost fuels and basic chemicals. Enormous investment over the last century has led to the development of a set of highly efficient catalytic processes which define the modern oil refinery and which produce most of the raw materials and fuels used in modern society. Process evolution and development has led to a refining infrastructure that is both dominated and enabled by modern heterogeneous catalyst technologies. Refineries and chemical manufacturers are currently under intense pressure to improve efficiency, adapt to increasingly disadvantaged feedstocks including biomass, lower their environmental footprint, and continue to deliver their products at low cost. This pressure creates a demand for new and more robust catalyst systems and processes that can accommodate them. Traditional methods of catalyst synthesis and testing are slow and inefficient, particularly in heterogeneous systems where the structure of the active sites is typically complex and the reaction mechanism is at best ill-defined. While theoretical modeling and a growing understanding of fundamental surface science help guide the chemist in designing and synthesizing targets, even in the most well understood areas of catalysis, the parameter space that one needs to explore experimentally is vast. The result is that the chemist using traditional methods must navigate a complex and unpredictable diversity space with a limited data set to make discoveries or to optimize known systems. We describe here a mature set of synthesis and screening technologies that together form a workflow that breaks this traditional paradigm and allows for rapid and efficient heterogeneous catalyst discovery and optimization. We exemplify the power of these new technologies by describing their use in the development and commercialization of a novel catalyst for the

  4. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C.H.

    1990-10-11

    This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for Fischer-Tropsch (FT) synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the thirteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made on the testing of the system hardware and software. H{sub 2} chemisorption capacities and activity selectivity data were also measured for three iron catalysts promoted with 1% alumina. 47 refs., 8 figs., 1 tab.

  5. Catalytic dehydration of ethanol using transition metal oxide catalysts.

    Science.gov (United States)

    Zaki, T

    2005-04-15

    The aim of this work is to study catalytic ethanol dehydration using different prepared catalysts, which include Fe(2)O(3), Mn(2)O(3), and calcined physical mixtures of both ferric and manganese oxides with alumina and/or silica gel. The physicochemical properties of these catalysts were investigated via X-ray powder diffraction (XRD), acidity measurement, and nitrogen adsorption-desorption at -196 degrees C. The catalytic activities of such catalysts were tested through conversion of ethanol at 200-500 degrees C using a catalytic flow system operated under atmospheric pressure. The results obtained indicated that the dehydration reaction on the catalyst relies on surface acidity, whereas the ethylene production selectivity depends on the catalyst chemical constituents.

  6. Experimental research of technology activating catalysts for SCR DeNOx in boiler

    Science.gov (United States)

    Zeng, Xi; Yang, Zhengde; Li, Yan; Chen, Donglin

    2018-01-01

    In order to improve activity of the catalysts used in SCR DeNOx system of flue gas, a series of catalysts activated by different activating liquids under varied conditions in boiler directly were conducted. Then these catalysts were characterized by SEM, FT-IR and BET technology. And NO conversions of the activated catalysts were studied and compared with that of inactivated catalyst. The above experiment shows that NO conversion of the activated catalyst can be up to 99%, which 30% higher than that of inactivated catalyst, so activity of catalysts were improved greatly. Furthermore, optimal activating liquid labeled L2 and effective technology parameters were gained in the experiment.

  7. Sputtered catalysts

    International Nuclear Information System (INIS)

    Tyerman, W.J.R.

    1978-01-01

    A method is described for preparing a supported catalyst by a sputtering process. A material that is catalytic, or which is a component of a catalytic system, is sputtered on to the surface of refractory oxide particles that are compatible with the sputtered material and the sputtered particles are consolidated into aggregate form. The oxide particles before sputtering should have a diameter in the range 1000A to 50μ and a porosity less than 0.4 ml/g, and may comprise MgO, Al 2 O 3 or SiO 2 or mixtures of these oxides, including hydraulic cement. The particles may possess catalytic activity by themselves or in combination with the catalytic material deposited on them. Sputtering may be effected epitaxially and consolidation may be effected by compaction pelleting, extrusion or spray drying of a slurry. Examples of the use of such catalysts are given. (U.K.)

  8. Highly dispersed metal catalyst

    Science.gov (United States)

    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.

  9. Liquefaction of kraft lignin by hydrocracking with simultaneous use of a novel dual acid-base catalyst and a hydrogenation catalyst.

    Science.gov (United States)

    Wang, Jindong; Li, Wenzhi; Wang, Huizhen; Ma, Qiaozhi; Li, Song; Chang, Hou-Min; Jameel, Hasan

    2017-11-01

    In this study, a novel catalyst, S 2 O 8 2- -KNO 3 /TiO 2 , which has active acidic and basic sites, was prepared and used in lignin hydrocracking with a co-catalyst, Ru/C. Ru/C is an efficient hydrogenation catalyst and S 2 O 8 2- -KNO 3 /TiO 2 is a dual catalyst, which could efficiently degrade lignin. This catalytic hydrogenation system can reduce solid products to less than 1%, while giving a high liquid product yield of 93%. Catalytic hydrocracking of kraft lignin at 320°C for 6h gave 93% liquid product with 0.5% solid product. Most of this liquid product was soluble in petroleum ether (60% of 93%), which is a clear liquid and comprises mainly of monomeric and dimeric degradation products. These results demonstrated that the combination of the two catalysts is an efficient catalyst for liquefaction of lignin, with little char formation (∼1%). This concept has the potential to produce valuable chemicals and fuels from lignin under moderate conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Preparation of supported heterogeneous catalysts by pulse impregnation: Application to Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Haukka, M.; Pakkanen, T.A. (Univ. of Joensuu (Finland))

    1994-07-01

    In this paper, the authors introduce pulse impregnation, a method for preparing supported heterogeneous catalysts by successive impregnation cycles. Pulse impregnation is a method for preparing supported heterogeneous catalysts from the liquid phase. In the pulse-impregnation technique the catalyst surface is grown gradually in consecutive cycles, with each cycle consisting of separate deposition and activation steps. During the deposition step, the catalyst precursor or precursors are deposited onto the support from a suitable solvent. The actual chemically bonded catalyst phase is formed during the activation step (e.g., thermal activation). Pulse impregnation was tested in the separate deposition of 2,2[prime]-bipyridine and Ru[sub 3](CO)[sub 12] onto a silica support, and in the preparation of Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst, in a column-type reactor system. Macroscopically uniform deposition was achieved with both 2,2[prime]-bipyridine and Ru[sub 3](CO)[sub 12]. Various solvent systems were used to control the amount of solute adsorbed during deposition. In the preparation of the Ru[sub 3](CO)[sub 12]/2,2[prime]-bipyridine/SiO[sub 2] catalyst, the ruthenium content increased nearly linearly with the number of preparation cycles. The effects of the preparation method on the catalyst activity was also tested in 1-hexane hydroformylation. 31 refs., 7 figs., 1 tab.

  11. Effect of coke and catalyst structure on oxidative regeneration of hydroprocessing catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. (CANMET, Ottawa, ON (Canada). Energy Research Laboratories)

    1991-04-01

    Two industrial hydroprocessing catalysts used for upgrading an atmospheric residue and a gas oil, respectively were regenerated in a fixed bed using air and 2 vol.% O{sub 2}+N{sub 2} balance mixture. The regeneration in air resulted in a significant sintering of the catalyst's material. The surface area of catalysts regenerated in 2 vol.% O{sub 2} mixture was similar to that of fresh catalysts, whereas a significant loss of surface area was observed after regeneration in air. The X-ray diffraction pattern of catalysts regenerated in 2 vol.% O{sub 2}+N{sub 2} balance mixture was also similar to that of fresh catalysts. 22 refs., 9 figs., 7 tabs.

  12. Online screening of homogeneous catalyst performance using reaction detection mass spectrometry

    NARCIS (Netherlands)

    Martha, C.T.; Elders, N.; Krabbe, J.G.; Kool, J.; Niessen, W.M.A.; Orru, R.V.A.; Irth, H.

    2008-01-01

    An integrated online screening system was developed to rapidly screen homogeneous catalysts for activity toward a selected synthesis. The continuous-flow system comprises standard HPLC pumps for the delivery of substrates, an HPLC autosampler for the injection of homogeneous catalysts, a

  13. Hydrogen production from bio-fuels using precious metal catalysts

    Science.gov (United States)

    Pasel, Joachim; Wohlrab, Sebastian; Rotov, Mikhail; Löhken, Katrin; Peters, Ralf; Stolten, Detlef

    2017-11-01

    Fuel cell systems with integrated autothermal reforming unit require active and robust catalysts for H2 production. Thus, an experimental screening of catalysts for autothermal reforming of commercial biodiesel fuel was performed. Catalysts consisted of a monolithic cordierite substrate, an oxide support (γ-Al2O3) and Pt, Ru, Ni, PtRh and PtRu as active phase. Experiments were run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. Fresh and aged catalysts were characterized by temperature programmed methods and thermogravimetry to find correlations with catalytic activity and stability.

  14. The nanosize catalysts role in the modern hydroprocesses

    International Nuclear Information System (INIS)

    Irisova, K N; Smirnov, V K; Talisman, E L

    2011-01-01

    Introduction of the modern technological procedures operating the catalytic systems with different nanosized characteristics is the only way to fabricate components of commercial oils that meet the current requirements. Specifications to the individual catalysts, which form a catalytic system, differ both in nanostructural features of the support porosity and in distribution of nanosized active site. These specifications are related to the purpose of the process and the role of the catalyst in the process.

  15. Hydroprocessing catalyst development

    Energy Technology Data Exchange (ETDEWEB)

    Boorman, P.M.; Kydd, R.A.; Sorensen, T.S.; Chong, K.; Lewis, J.

    1992-08-01

    Co-Mo and Ni-Mo hydroprocessing catalysts were examined for their activity in removal of sulfur from thiophene in model compounds, and in the cracking and hydrocracking of cumene. Three types of support materials were examined: carbon, modified carbon, and carbon covered alumina. The objective of the study was to examine the correlation between catalyst activity in the hydrodenitrogenation of model compounds, and the resistance of the catalyst to nitrogen poisoning during use in the hydroprocessing of gas oils. The use of model compound testing provided information on the individual catalytic reactions promoted by those materials. Infrared spectroscopy was used to study surface species on the catalysts and to explain many of the trends in activity observed, revealing the role of fluoride and phosphorus as a secondary promoter. Testing of the catalysts in hydrotreating of gas oils allowed comparison of model compound results with those from a real feedstock. The gas oil was also spiked with a model nitrogen compound and the results from catalytic hydrotreating of this material were compared with those from unspiked material. A key finding was that the carbon supported catalysts were the most effective in treating high-nitrogen feeds. The very favorable deactivation properties of carbon and carbon-covered alumina supported catalysts make these promising from an industrial point of view where catalyst deactivation is a limiting factor. 171 refs., 25 figs., 43 tabs.

  16. Computationally Probing the Performance of Hybrid, Heterogeneous, and Homogeneous Iridium-Based Catalysts for Water Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    García-Melchor, Max [SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford CA (United States); Vilella, Laia [Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST),Tarragona (Spain); Departament de Quimica, Universitat Autonoma de Barcelona, Barcelona (Spain); López, Núria [Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Tarragona (Spain); Vojvodic, Aleksandra [SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park CA (United States)

    2016-04-29

    An attractive strategy to improve the performance of water oxidation catalysts would be to anchor a homogeneous molecular catalyst on a heterogeneous solid surface to create a hybrid catalyst. The idea of this combined system is to take advantage of the individual properties of each of the two catalyst components. We use Density Functional Theory to determine the stability and activity of a model hybrid water oxidation catalyst consisting of a dimeric Ir complex attached on the IrO2(110) surface through two oxygen atoms. We find that homogeneous catalysts can be bound to its matrix oxide without losing significant activity. Hence, designing hybrid systems that benefit from both the high tunability of activity of homogeneous catalysts and the stability of heterogeneous systems seems feasible.

  17. Metal-Organic-Framework mediated supported-cobalt catalysts in multiphase hydrogenation reactions

    OpenAIRE

    Sun, X.

    2017-01-01

    The production of most industrially important chemicals involves catalysis. Depending on the difference in phases between the catalysts and reactants, one distinguishes homogenous catalysis and heterogeneous catalysis, with the latter being more attractive in real applications, due to the easy separation of products from catalysts and reusing the latter. In spite of the research and development of heterogeneous catalysts for decades, the exploration for catalysts system with outstanding activ...

  18. Preparation of inorganic hydrophobic catalysts

    International Nuclear Information System (INIS)

    Yang, Yong; Wang, Heyi; Du, Yang

    2009-04-01

    In order to catalyse the oxidation of tritium gas, two inorganic hydrophobic catalysts are prepared. Under room temperature, the catalysed oxidation ratio of 0.3%-1% (V/V) hydrogen gas in air is higher than 95%. Pt-II inorganic hydrophobic catalysts has obviously better catalysing ability than Pt-PTFE and lower ability than Pt-SDB in H 2 -HTO isotopic exchange, because the pressure resistence of Pt-II is much higher than Pt-SDB, it can be used to the CECE cell of heavy water detritium system. (authors)

  19. Full Scale Alternative Catalyst Testing for Bosch Reactor Optimization

    Science.gov (United States)

    Barton, Katherine; Abney, Morgan B.

    2011-01-01

    Current air revitalization technology onboard the International Space Station (ISS) cannot provide complete closure of the oxygen and hydrogen loops. This makes re-supply necessary, which is possible for missions in low Earth orbit (LEO) like the ISS, but unviable for long term space missions outside LEO. In comparison, Bosch technology reduces carbon dioxide with hydrogen, traditionally over a steel wool catalyst, to create water and solid carbon. The Bosch product water can then be fed to the oxygen generation assembly to produce oxygen for crew members and hydrogen necessary to reduce more carbon dioxide. Bosch technology can achieve complete oxygen loop closure, but has many undesirable factors that result in a high energy, mass, and volume system. Finding a different catalyst with an equal reaction rate at lower temperatures with less catalyst mass and longer lifespan would make a Bosch flight system more feasible. Developmental testing of alternative catalysts for the Bosch has been performed using the Horizontal Bosch Test Stand. Nickel foam, nickel shavings, and cobalt shavings were tested at 500 C and compared to the original catalyst, steel wool. This paper presents data and analysis on the performance of each catalyst tested at comparable temperatures and recycle flow rates.

  20. Effects of Cu over Pd based catalysts supported on silica or niobia

    Directory of Open Access Journals (Sweden)

    Roma M.N.S.C.

    2000-01-01

    Full Text Available Palladium and palladium-copper catalysts supported on silica and niobia were characterized by H2 chemisorption and H2-O2 titration. Systems over silica were also analyzed by transmission electron microscopy and EXAFS. The metallic dispersion decreased from 20% to 7% when the content of Pd was increased from 0.5wt.-% to 3wt.-% in monometallic catalysts. The addition of 3 wt.-% Cu to obtain Pd-Cu catalysts caused a remarkable capacity loss of hydrogen chemisorption. TPR analysis suggested an interaction between the two metals and EXAFS characterization of the catalyst supported on silica confirmed the formation of Pd-Cu alloy. Pd/Nb2O5 catalysts showed turnover numbers higher than those obtained with the Pd/SiO2 systems in the cyclohexane dehydrogenation. However, the bimetallic catalysts showed very low turnover numbers.

  1. Radio-Frequency-Controlled Urea Dosing for NH₃-SCR Catalysts: NH₃ Storage Influence to Catalyst Performance under Transient Conditions.

    Science.gov (United States)

    Dietrich, Markus; Hagen, Gunter; Reitmeier, Willibald; Burger, Katharina; Hien, Markus; Grass, Philippe; Kubinski, David; Visser, Jaco; Moos, Ralf

    2017-11-28

    Current developments in exhaust gas aftertreatment led to a huge mistrust in diesel driven passenger cars due to their NO x emissions being too high. The selective catalytic reduction (SCR) with ammonia (NH₃) as reducing agent is the only approach today with the capability to meet upcoming emission limits. Therefore, the radio-frequency-based (RF) catalyst state determination to monitor the NH₃ loading on SCR catalysts has a huge potential in emission reduction. Recent work on this topic proved the basic capability of this technique under realistic conditions on an engine test bench. In these studies, an RF system calibration for the serial type SCR catalyst Cu-SSZ-13 was developed and different approaches for a temperature dependent NH₃ storage were determined. This paper continues this work and uses a fully calibrated RF-SCR system under transient conditions to compare different directly measured and controlled NH₃ storage levels, and NH₃ target curves. It could be clearly demonstrated that the right NH₃ target curve, together with a direct control on the desired level by the RF system, is able to operate the SCR system with the maximum possible NO x conversion efficiency and without NH₃ slip.

  2. 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.

  3. The Pd-catalyzed semihydrogenation of alkynes to Z-alkenes: Catalyst systems and the type of active species

    NARCIS (Netherlands)

    Drost, R.M.

    2014-01-01

    In this thesis studies have been performed on the Pd-catalyzed Z-selective semihydrogenation of alkynes. In Chapter one a general introduction is given. In Chapter two a new NHC-based, easy-to-use catalyst system is developed. The performance of the system is evaluated for a range of alkynes. In

  4. Effect of Catalyst Pellet-Diameter and Basicity on Transesterification of Soybean Oil into Biodiesel using K2O/CaO-ZnO Catalyst over Hybrid Catalytic-Plasma Reactor

    Directory of Open Access Journals (Sweden)

    Istadi I.

    2018-01-01

    Full Text Available This research is aimed to study the effect of catalyst pellet-diameter and catalyst basicity on the transesterification process of soybean oil into biodiesel over a hybrid catalytic-plasma reactor. Various catalyst diameters (3, 5, and 7 mm were tested in this reaction system. Catalyst basicity was also examined by comparing fresh and used catalyst as well as with and without K2O promoter. All catalysts testing were performed in a hybrid plasma-catalytic reactor (dielectric barrier discharge – DBD type. From the results, the synergistic effects roles of the catalyst and the plasma in the transesterification process are important, in which the energetic electrons within plasma assist the reaction on the catalyst surface by an exciting bonded electron. The catalyst basicity was influenced by the composition of CaO on the catalyst as well as roles of the alkaline K2O promoter. Catalyst basicity is important in producing biodiesel with high performance. Yield of fatty acid alkyl ester (FAAE or biodiesel is slightly influenced by the catalyst diameter within the range of diameter studied.

  5. Ledge-flow-controlled catalyst interface dynamics during Si nanowire growth

    DEFF Research Database (Denmark)

    Hofmann, S; Sharma, R; Wirth, CT

    2008-01-01

    understanding of the role of commonly used catalysts and specifically of their interface dynamics1, 2. Although catalytic chemical vapour deposition of nanowires below the eutectic temperature has been demonstrated in many semiconductor–catalyst systems3, 4, 5, 6, growth from solid catalysts is still disputed...... as a comparative benchmark. The dominant coherent Pd silicide/Si growth interface subsequently advances by lateral propagation of ledges, driven by catalytic dissociation of disilane and coupled Pd and Si diffusion. Our results establish an atomistic framework for nanowire assembly from solid catalysts, relevant...

  6. Oxidation of methyl heterocyclic compounds on vanadium oxide catalysts

    International Nuclear Information System (INIS)

    Shimanskaya, M.V.; Lejtis, L.A.; Iovel', I.G.; Gol'dberg, Yu.Sh.; Skolmejstere, R.A.; Golender, L.O.

    1985-01-01

    Data on vapor-phase oxidation of methyl derivatives of thiophene, Δ 2 - thiazo line, pyridine, pyrazine and pyramidine on oxide vanadium-molybdenum catalysts to corresponding heterylaldehydes are generalized. The dependence of catalytic properties of oxide vanadium-molybdenum systems in oxidation reactions of methylheterocyclic compounds on V:Mo ratio in the catalyst is revealed. It is shown that heterocyclic compounds are coordinated by a heteroatom on Lewis centres of V-Mo-O-catalyst primarily with partially reduced vanadium ions

  7. Supramolecular water oxidation with rubda-based catalysts

    KAUST Repository

    Richmond, Craig J.

    2014-11-05

    Extremely slow and extremely fast new water oxidation catalysts based on the Rubda (bda = 2,2′-bipyri-dine-6,6′-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycless"1, respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system p-stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts.

  8. Hydrogen production from bio-fuels using precious metal catalysts

    Directory of Open Access Journals (Sweden)

    Pasel Joachim

    2017-01-01

    Full Text Available Fuel cell systems with integrated autothermal reforming unit require active and robust catalysts for H2 production. Thus, an experimental screening of catalysts for autothermal reforming of commercial biodiesel fuel was performed. Catalysts consisted of a monolithic cordierite substrate, an oxide support (γ-Al2O3 and Pt, Ru, Ni, PtRh and PtRu as active phase. Experiments were run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. Fresh and aged catalysts were characterized by temperature programmed methods and thermogravimetry to find correlations with catalytic activity and stability.

  9. Predictive Modelling of Phase-Transfer Catalyst Systems for Improved and Innovative Design

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Hyung Kim, Sun; Sales-Cruz, Mauricio

    2016-01-01

    Phase-transfer catalyst (PTC) systems contain two immiscible liquid phases with a heterogeneous PTC transferring active ion from one phase to the other for converting the reactant to the desired product, and in the process generating the inactive ion. This type of reacting systems is receiving...... increasing attention as a novel organic synthesis option due to its flexible and easier operation, higher production yield, and ability to eliminate expensive solvents, although, not eliminating the use of solvents. New mathematical models of the PTC system, which includes physical and chemical equilibrium......, reaction mechanism and unit operation has been developed. In the developed model, the PTC system is divided into four sub-systems of aqueous-organic solvent partition, inorganic salt in aqueous phase, PTC in aqueous phase, and PTC in aqueous phase. Each subsystem requires an appropriate thermodynamic model...

  10. Catalyst activity maintenance study for the liquid phase dimethyl ether process

    Energy Technology Data Exchange (ETDEWEB)

    Peng, X.D.; Toseland, B.A.; Underwood, R.P. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1995-12-31

    The co-production of dimethyl ether (DME) and methanol from syngas is a process of considerable commercial attractiveness. DME coproduction can double the productivity of a LPMEOH process when using coal-derived syngas. This in itself may offer chemical producers and power companies increased flexibility and more profitable operation. DME is also known as a clean burning liquid fuel; Amoco and Haldor-Topsoe have recently announced the use of DME as an alternative diesel fuel. Moreover, DME can be an interesting intermediate in the production of chemicals such as olefins and vinyl acetate. The current APCl liquid phase dimethyl ether (LPDME) process utilizes a physical mixture of a commercial methanol synthesis catalyst and a dehydration catalyst (e.g., {gamma}-alumina). While this arrangement provides a synergy that results in much higher syngas conversion per pass compared to the methanol-only process, the stability of the catalyst system suffers. The present project is aimed at reducing catalyst deactivation both by understanding the cause(s) of catalyst deactivation and by developing modified catalyst systems. This paper describes the current understanding of the deactivation mechanism.

  11. Catalyst development and systems analysis of methanol partial oxidation for the fuel processor - fuel cell integration

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E; Mizsey, P; Hottinger, P; Truong, T B; Roth, F von; Schucan, Th H [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Methanol partial oxidation (pox) to produce hydrogen for mobile fuel cell applications has proved initially more successful than hydrocarbon pox. Recent results of catalyst screening and kinetic studies with methanol show that hydrogen production rates have reached 7000 litres/hour/(litre reactor volume) for the dry pox route and 12,000 litres/hour/(litre reactor volume) for wet pox. These rates are equivalent to 21 and 35 kW{sub th}/(litre reactor volume) respectively. The reaction engineering problems remain to be solved for dry pox due to the significant exotherm of the reaction (hot spots of 100-200{sup o}C), but wet pox is essentially isothermal in operation. Analyses of the integrated fuel processor - fuel cell systems show that two routes are available to satisfy the sensitivity of the fuel cell catalysts to carbon monoxide, i.e. a preferential oxidation reactor or a membrane separator. Targets for individual system components are evaluated for the base and best case systems for both routes to reach the combined 40% efficiency required for the integrated fuel processor - fuel cell system. (author) 2 figs., 1 tab., 3 refs.

  12. Communicating catalysts

    Science.gov (United States)

    Weckhuysen, Bert M.

    2018-06-01

    The beauty and activity of enzymes inspire chemists to tailor new and better non-biological catalysts. Now, a study reveals that the active sites within heterogeneous catalysts actively cooperate in a fashion phenomenologically similar to, but mechanistically distinct, from enzymes.

  13. Recombination Catalysts for Hypersonic Fuels

    Science.gov (United States)

    Chinitz, W.

    1998-01-01

    The goal of commercially-viable access to space will require technologies that reduce propulsion system weight and complexity, while extracting maximum energy from the products of combustion. This work is directed toward developing effective nozzle recombination catalysts for the supersonic and hypersonic aeropropulsion engines used to provide such access to space. Effective nozzle recombination will significantly reduce rk=le length (hence, propulsion system weight) and reduce fuel requirements, further decreasing the vehicle's gross lift-off weight. Two such catalysts have been identified in this work, barium and antimony compounds, by developing chemical kinetic reaction mechanisms for these materials and determining the engine performance enhancement for a typical flight trajectory. Significant performance improvements are indicated, using only 2% (mole or mass) of these compounds in the combustor product gas.

  14. Methods of making textured catalysts

    Science.gov (United States)

    Werpy, Todd [West Richland, WA; Frye, Jr., John G.; Wang, Yong [Richland, WA; Zacher, Alan H [Kennewick, WA

    2010-08-17

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  15. Magnetic nanoparticles conjugated to chiral imidazolidinone as recoverable catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Mondini, Sara [Consiglio Nazionale delle Ricerche, Laboratorio di Nanotecnologie, Istituto di Scienze e Tecnologie Molecolari (Italy); Puglisi, Alessandra; Benaglia, Maurizio, E-mail: maurizio.benaglia@unimi.it; Ramella, Daniela [Università degli Studi di Milano, Dipartimento di Chimica (Italy); Drago, Carmelo [Consiglio Nazionale delle Ricerche, Istituto di Chimica Biomolecolare (Italy); Ferretti, Anna M.; Ponti, Alessandro, E-mail: alessandro.ponti@istm.cnr.it [Consiglio Nazionale delle Ricerche, Laboratorio di Nanotecnologie, Istituto di Scienze e Tecnologie Molecolari (Italy)

    2013-11-15

    The immobilization of an ad hoc designed chiral imidazolidin-4-one onto iron oxide magnetic nanoparticles (MNPs) is described, to afford MNP-supported MacMillan’s catalyst. Morphological and structural analysis of the materials, during preparation, use, and recycle, has been carried out by transmission electron microscopy. The supported catalyst was tested in the Diels–Alder reaction of cyclopentadiene with cinnamic aldehyde, affording the products in good yields and enantiomeric excesses up to 93 %, comparable to those observed with the non-supported catalyst. Recovery of the chiral catalyst has been successfully performed by simply applying an external magnet to achieve a perfect separation of the MNPs from the reaction product. The recycle of the catalytic system has been also investigated. Noteworthy, this immobilized MacMillan’s catalyst proved to be able to efficiently promote the reaction in pure water.

  16. Magnetic nanoparticles conjugated to chiral imidazolidinone as recoverable catalyst

    International Nuclear Information System (INIS)

    Mondini, Sara; Puglisi, Alessandra; Benaglia, Maurizio; Ramella, Daniela; Drago, Carmelo; Ferretti, Anna M.; Ponti, Alessandro

    2013-01-01

    The immobilization of an ad hoc designed chiral imidazolidin-4-one onto iron oxide magnetic nanoparticles (MNPs) is described, to afford MNP-supported MacMillan’s catalyst. Morphological and structural analysis of the materials, during preparation, use, and recycle, has been carried out by transmission electron microscopy. The supported catalyst was tested in the Diels–Alder reaction of cyclopentadiene with cinnamic aldehyde, affording the products in good yields and enantiomeric excesses up to 93 %, comparable to those observed with the non-supported catalyst. Recovery of the chiral catalyst has been successfully performed by simply applying an external magnet to achieve a perfect separation of the MNPs from the reaction product. The recycle of the catalytic system has been also investigated. Noteworthy, this immobilized MacMillan’s catalyst proved to be able to efficiently promote the reaction in pure water

  17. Multiphase catalysts for selective reduction of NOx with hydrocarbons

    International Nuclear Information System (INIS)

    Maisuls, S.E.

    2000-01-01

    catalyst with Rh was studied and the results are summarized in Chapter 6. Chapter 7 presents a comparison between the Co-Pt and Co-Rh systems. Finally, we evaluate the results of this study and general conclusions with suggestions for the design of an optimal deNOx catalyst. refs

  18. In-situ hydrodeoxygenation of phenol by supported Ni catalyst-explanation for catalyst performance

    DEFF Research Database (Denmark)

    Wang, Ze; Zeng, Ying; Lin, Weigang

    2017-01-01

    In-situ hydrodeoxygenation of phenol with aqueous hydrogen donor over supported Ni catalyst was investigated. The supported Ni catalysts exerted very poor performance, if formic acid was used as the hydrogen donor. Catalyst modification by loading K, Na, Mg or La salt could not make the catalyst...... performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....

  19. Non-PGM cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Elvington, M. [Savannah River Consulting, Aiken, SC (United States); Ganesan, P. [Savannah River Consulting, Aiken, SC (United States)

    2017-09-27

    A unique approach has been developed to probe the non-PGM catalyst active site for the Oxygen Reduction Reaction (ORR) for PEMFCs. Iron based functionalities have been engineered into a variety of catalysts to evaluate their impact on activity for the ORR. A series of high surface area catalysts were synthesized and the impact of the chemical structure on the electrochemical and electrocatalytic properties was investigated. Elemental and surface analyses of the prepared catalysts reveal the incorporation of iron in a targeted and controlled manner. A high surface area framework catalyst was prepared that shows exceptional activity, comparable to state-of-the-art materials. The results of this research project provided critical seed data for the newly awarded ElectroCat project, which focuses on rationally designed framework catalysts for the oxygen reduction reaction.

  20. 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...... of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water....

  1. Transition Metal Catalyzed Hydroarylation of Multiple Bonds: Exploration of Second Generation Ruthenium Catalysts and Extension to Copper Systems

    Energy Technology Data Exchange (ETDEWEB)

    T. Brent Gunnoe

    2011-02-17

    Catalysts provide foundational technology for the development of new materials and can enhance the efficiency of routes to known materials. New catalyst technologies offer the possibility of reducing energy and raw material consumption as well as enabling chemical processes with a lower environmental impact. The rising demand and expense of fossil resources has strained national and global economies and has increased the importance of accessing more efficient catalytic processes for the conversion of hydrocarbons to useful products. The goals of the research are to develop and understand single-site homogeneous catalysts for the conversion of readily available hydrocarbons into useful materials. A detailed understanding of these catalytic reactions could lead to the development of catalysts with improved activity, longevity and selectivity. Such transformations could reduce the environmental impact of hydrocarbon functionalization, conserve energy and valuable fossil resources and provide new technologies for the production of liquid fuels. This project is a collaborative effort that incorporates both experimental and computational studies to understand the details of transition metal catalyzed C-H activation and C-C bond forming reactions with olefins. Accomplishments of the current funding period include: (1) We have completed and published studies of C-H activation and catalytic olefin hydroarylation by TpRu{l_brace}P(pyr){sub 3}{r_brace}(NCMe)R (pyr = N-pyrrolyl) complexes. While these systems efficiently initiate stoichiometric benzene C-H activation, catalytic olefin hydroarylation is hindered by inhibition of olefin coordination, which is a result of the steric bulk of the P(pyr){sub 3} ligand. (2) We have extended our studies of catalytic olefin hydroarylation by TpRu(L)(NCMe)Ph systems to L = P(OCH{sub 2}){sub 3}CEt. Thus, we have now completed detailed mechanistic studies of four systems with L = CO, PMe{sub 3}, P(pyr){sub 3} and P(OCH{sub 2}){sub 3}CEt

  2. Vibration measurements of automobile catalyst

    Science.gov (United States)

    Aatola, Seppo

    1994-09-01

    Vibration of catalyst cell, which is inside the casing of the catalyst, is difficult to measure with usual measuring instrumentation. When catalyst is in use, there is hot exhaust gas flow though the catalyst cell and temperature of the cell is approximately +900 degree(s)C. Therefore non-contact Laser- Doppler-Vibrometer was used to measure vibration velocity of the catalyst cell. The laser beam was directed towards the cell through pipe which was put through and welded to the casing of the catalyst. The outer end of the pipe was screw down with a tempered class to prevent exhaust gas flow from the pipe. The inner end of the pipe was open and few millimeters away from the measuring point. Catalyst was attached to the engine with two ways, rigidly close to the engine and flexible under the engine. The engine was running in test bench under controlled conditions. Vibration measurements were carried out during constant running speeds of the engine. Vibration signals were captured and analyzed with FFT-analyzer. Vibration of catalyst cell was strongest at running speed of 5000 rpm, from 10 to 20 g (1 g equals 9.81 ms-2), when catalyst was attached rigidly close to the engine. At running speed of 3000 rpm, vibration of catalyst cell was from 2 to 3 g in most cases, when catalyst was attached either rigidly or flexible to the engine. It is estimated that in real life, i.e. when catalyst is attached to car with same engine, vibration of catalyst cell at running speed of 5000 rpm is somewhere between 1 and 10 g. At running speed of 3000 rpm, which may be more often used when driving car (car speed approximately 100 kmh-1), vibration of catalyst cell is probably few g's.

  3. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  4. 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.

  5. Characterization of catalysts by Moessbauer spectroscopy: An application to the study of Fischer-Tropsch, hydrotreating and super Claus catalysts

    International Nuclear Information System (INIS)

    Kraan, A.M. van der; Boellaard, E.; Craje, M.W.J.

    1993-01-01

    Moessbauer spectroscopy is an excellent in-situ technique for the identification of phases present in catalysts. Applied to metallic iron catalysts used in the Fischer-Tropsch reaction it reveals a detailed picture of the carburization process and provides insight into the relation between the properties of the catalytic material and its activity. The influence of a support and the effect of alloying iron with an (in)active metal on the catalytic performance is discussed for Fe, Cu-Fe and Ni-Fe systems. In addition, Moessbauer spectroscopy is used for the identification of 'Co-sulfide' species present in sulfided Co and CoMo catalysts applied in one of the largest chemical processes in the world, the hydrotreatment of crude oil. A structural model is proposed. Finally, the contribution of Moessbauer spectroscopic studies to the development of a new catalyst for cleaning of Claus tail gas via selective oxidation of hydrogen sulfide to elemental sulfur is discussed. (orig.)

  6. 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.

  7. Polypropylene obtained through zeolite supported catalysts

    International Nuclear Information System (INIS)

    Bastos, Queli C.; Marques, Maria de Fatima V.

    2004-01-01

    Propylene polymerizations were carried out with φ 2 C(Flu)(Cp)ZrCl 2 and SiMe 2 (Ind)2ZrCl 2 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 f 2 C(Flu)(Cp)ZrCl 2 , SiO 2 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 stereo regularity. (author)

  8. Design of sintering-stable heterogeneous catalysts

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata

    One of the major issues in the use of metal nanoparticles in heterogeneous catalysis is sintering. Sintering occurs at elevated temperatures because of increased mobility of nanoparticles, leading to their agglomeration and, as a consequence, to the deactivation of the catalyst. It is an emerging...... problem especially for the noble metals-based catalysis. These metals being expensive and scarce, it is worth developing catalyst systems which preserve their activity over time. Encapsulation of nanoparticles inside zeolites is one of the ways to prevent sintering. Entrapment of nanoparticles inside...

  9. Poly(Ionic Liquid: A New Phase in a Thermoregulated Phase Separated Catalysis and Catalyst Recycling System of Transition Metal-Mediated ATRP

    Directory of Open Access Journals (Sweden)

    Lan Yao

    2018-03-01

    Full Text Available Poly(ionic liquids (PILs have become the frontier domains in separation science because of the special properties of ionic liquids as well as their corresponding polymers. Considering their function in separation, we designed and synthesized a thermoregulated PIL. That is, this kind of PIL could separate with an organic phase which dissolves the monomers at ambient temperature. When heated to the reaction temperature, they become a homogeneous phase, and they separate again when the temperature falls to the ambient temperature after polymerization. Based on this, a thermoregulated phase separated catalysis (TPSC system for Cu-based atom transfer radical polymerization (ATRP was constructed. The copper catalyst (CuBr2 used here is easily separated and recycled in situ just by changing the temperature in this system. Moreover, even when the catalyst had been recycled five times, the controllability over resultant polymers is still satisfying. Finally, only 1~2 ppm metal catalyst was left in the polymer solution phase, which indicates the really high recycling efficiency.

  10. Oscillatory behaviour of isomers of hydroxybenzoic acid with and without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Masood A.; Rastogi, R.P.; Peerzada, G.M. [University of Kashmir, Srinagar (India). Dept. of Chemistry]. E-mail: nath_masood@yahoo.co.in

    2009-07-01

    The present work establishes and compares the oscillatory behaviour of mono-, di- and trihydroxybenzoic acids as organic substrates in acidic bromate (1.0 mol L{sup -1} H{sub 2}SO{sub 4}) without catalyst and in the presence of Mn{sup 2+} ion as the main catalyst. The oscillations are also affected by other catalyst such as Fe{sup 2+} ion. Further, the oscillations start diminishing in mixed catalyst systems. The experimental parameters were obtained potentiometrically and the results have been interpreted on the basis of FKN mechanism. (author)

  11. Complex catalysts from self-repairing ensembles to highly reactive air-based oxidation systems

    Science.gov (United States)

    Craig L. Hill; Laurent Delannoy; Dean C. Duncan; Ira A. Weinstock; Roman F. Renneke; Richard S. Reiner; Rajai H. Atalla; Jong Woo Han; Daniel A. Hillesheim; Rui Cao; Travis M. Anderson; Nelya M. Okun; Djamaladdin G. Musaev; Yurii V. Geletii

    2007-01-01

    Progress in four interrelated catalysis research efforts in our laboratory are summarized: (1) catalytic photochemical functionalization of unactivated CeH bonds by polyoxometalates (POMs); (2) self-repairing catalysts; (3) catalysts for air-based oxidations under ambient conditions; and (4) terminal oxo complexes of the late-transition metal elements and their...

  12. Wafer scale integration of catalyst dots into nonplanar microsystems

    DEFF Research Database (Denmark)

    Gjerde, Kjetil; Kjelstrup-Hansen, Jakob; Gammelgaard, Lauge

    2007-01-01

    In order to successfully integrate bottom-up fabricated nanostructures such as carbon nanotubes or silicon, germanium, or III-V nanowires into microelectromechanical systems on a wafer scale, reliable ways of integrating catalyst dots are needed. Here, four methods for integrating sub-100-nm...... diameter nickel catalyst dots on a wafer scale are presented and compared. Three of the methods are based on a p-Si layer utilized as an in situ mask, an encapsulating layer, and a sacrificial window mask, respectively. All methods enable precise positioning of nickel catalyst dots at the end...

  13. Tritium inventories and tritium safety design principles for the fuel cycle of ITER

    International Nuclear Information System (INIS)

    Cristescu, I.R.; Cristescu, I.; Doerr, L.; Glugla, M.; Murdoch, D.

    2007-01-01

    Within the tritium plant of ITER a total inventory of about 2-3 kg will be necessary to operate the machine in the DT phase. During plasma operation, tritium will be distributed in the different sub-systems of the fuel cycle. A tool for tritium inventory evaluation within each sub-system of the fuel cycle is important with respect to both the process of licensing ITER and also for operation. It is very likely that measurements of total tritium inventories may not be possible for all sub-systems; however, tritium accounting may be achieved by modelling its hold-up within each sub-system and by validating these models in real-time against the monitored flows and tritium streams between the sub-systems. To get reliable results, an accurate dynamic modelling of the tritium content in each sub-system is necessary. A dynamic model (TRIMO) for tritium inventory calculation reflecting the design of each fuel cycle sub-systems was developed. The amount of tritium needed for ITER operation has a direct impact on the tritium inventories within the fuel cycle sub-systems. As ITER will function in pulses, the main characteristics that influence the rapid tritium recovery from the fuel cycle as necessary for refuelling are discussed. The confinement of tritium within the respective sub-systems of the fuel cycle is one of the most important safety objectives. The design of the deuterium/tritium fuel cycle of ITER includes a multiple barrier concept for the confinement of tritium. The buildings are equipped with a vent detritiation system and re-circulation type room atmosphere detritiation systems, required for tritium confinement barrier during possible tritium spillage events. Complementarily to the atmosphere detritiation systems, in ITER a water detritiation system for tritium recovery from various sources will also be operated

  14. Steam Reforming of Acetic Acid over Co-Supported Catalysts: Coupling Ketonization for Greater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, Stephen D. [Energy and Environmental; Spies, Kurt A. [Energy and Environmental; Mei, Donghai [Energy and Environmental; Kovarik, Libor [Energy and Environmental; Kutnyakov, Igor [Energy and Environmental; Li, Xiaohong S. [Energy and Environmental; Lebarbier Dagle, Vanessa [Energy and Environmental; Albrecht, Karl O. [Energy and Environmental; Dagle, Robert A. [Energy and Environmental

    2017-09-11

    We report on the markedly improved stability of a novel 2-bed catalytic system, as compared to a conventional 1-bed steam reforming catalyst, for the production of H2 from acetic acid. The 2-bed catalytic system comprises of i) a basic oxide ketonization catalyst for the conversion of acetic acid to acetone, and a ii) Co-based steam reforming catalyst, both catalytic beds placed in sequence within the same unit operation. Steam reforming catalysts are particularly prone to catalytic deactivation when steam reforming acetic acid, used here as a model compound for the aqueous fraction of bio-oil. Catalysts comprising MgAl2O4, ZnO, CeO2, and activated carbon (AC) both with and without Co-addition were evaluated for conversion of acetic acid and acetone, its ketonization product, in the presence of steam. It was found that over the bare oxide support only ketonization activity was observed and coke deposition was minimal. With addition of Co to the oxide support steam reforming activity was facilitated and coke deposition was significantly increased. Acetone steam reforming over the same Co-supported catalysts demonstrated more stable performance and with less coke deposition than with acetic acid feedstock. DFT analysis suggests that over Co surface CHxCOO species are more favorably formed from acetic acid versus acetone. These CHxCOO species are strongly bound to the Co catalyst surface and could explain the higher propensity for coke formation from acetic acid. Based on these findings, in order to enhance stability of the steam reforming catalyst a dual-bed (2-bed) catalyst system was implemented. Comparing the 2-bed and 1-bed (Co-supported catalyst only) systems under otherwise identical reaction conditions the 2-bed demonstrated significantly improved stability and coke deposition was decreased by a factor of 4.

  15. Apparatus and Process for Controlled Nanomanufacturing Using Catalyst Retaining Structures

    Science.gov (United States)

    Nguyen, Cattien (Inventor)

    2013-01-01

    An apparatus and method for the controlled fabrication of nanostructures using catalyst retaining structures is disclosed. The apparatus includes one or more modified force microscopes having a nanotube attached to the tip portion of the microscopes. An electric current is passed from the nanotube to a catalyst layer of a substrate, thereby causing a localized chemical reaction to occur in a resist layer adjacent the catalyst layer. The region of the resist layer where the chemical reaction occurred is etched, thereby exposing a catalyst particle or particles in the catalyst layer surrounded by a wall of unetched resist material. Subsequent chemical vapor deposition causes growth of a nanostructure to occur upward through the wall of unetched resist material having controlled characteristics of height and diameter and, for parallel systems, number density.

  16. Potential application of palladium nanoparticles as selective recyclable hydrogenation catalysts

    International Nuclear Information System (INIS)

    Mukherjee, DebKumar

    2008-01-01

    The search for more efficient catalytic systems that might combine the advantages of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis is one of the most exciting challenges of modern chemistry. More recently with the advances of nanochemistry, it has been possible to prepare soluble analogues of heterogeneous catalysts. These nanoparticles are generally stabilized against aggregation into larger particles by electrostatic or steric protection. Herein we demonstrate the use of room temperature ionic liquid for the stabilization of palladium nanoparticles that are recyclable catalysts for the hydrogenation of carbon-carbon double bonds and application of these catalysts to the selective hydrogenation of internal or terminal C=C bonds in unsaturated primary alcohols. The particles suspended in room temperature ionic liquid show no metal aggregation or loss of catalytic activity even on prolonged use

  17. 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

  18. In-situ catalytic upgrading of biomass pyrolysis vapor: Using a cascade system of various catalysts in a multi-zone fixed bed reactor

    International Nuclear Information System (INIS)

    Asadieraghi, Masoud; Wan Daud, Wan Mohd Ashri

    2015-01-01

    Highlights: • A cascade system of different catalysts exhibited the best performance to produce high quality bio-oil. • Meso-HZSM-5, Ga (1 wt.%)/meso-HZSM-5 and Cu (5 wt.%)/SiO 2 were employed in a cascade system. • The incorporation of the appropriate gallium amount to meso-HZSM-5 enhanced the aromatics selectivity. • Meso-HZSM-5 indicated a very good activity in bio-oil upgrading. - Abstract: The in-situ catalytic upgrading of palm kernel shell (PKS) fast pyrolysis vapors was performed over each individual meso-H-ZSM-5, Ga/meso-HZSM-5 and Cu/SiO 2 catalyst or a cascade system of them in a multi-zone fixed bed reactor. The effects of mesoporosity creation into the parent H-ZSM-5 catalyst and also gallium incorporation into mesoporous H-ZSM-5 on the produced bio-oil chemical composition and distribution were studied. Key upgrading reactions for different oxygenated compounds in pyrolysis oil (small oxygenates, lignin derived and sugar derived components), including aldol condensation, alkylation, hydrogenation, aromatization, and deoxygenation were discussed. The catalysts were characterized using SEM, XRF, XRD, N 2 adsorption and NH 3 -TPD methods. Furthermore, the produced bio-oils (catalytic and non-catalytic) were analyzed using GC–MS, FTIR, CHNS/O elemental analyzer and Karl Fischer titration. Production of the upgraded bio-oil with lower content of oxygenated compound was the main objective of this investigation. Among different catalysts, meso-H-ZSM-5 zeolite demonstrated a very good activity in aromatization and deoxygenation during the upgrading of pyrolytic vapors, although it decreased the bio-oil yield (32.6 wt.%). The gallium incorporation into the meso-HZSM-5 zeolite increased the bio-oil yield from 32.6 wt.% (meso-HZSM-5) to 35.8 wt.% (using 1.0 wt.% Ga). Furthermore, the aromatics selectivity was enhanced when the appropriate amount of gallium (1.0 wt.%) was introduced. A cascade system of various catalysts comprising meso-HZSM-5, Ga (1

  19. Advanced development of catalysts by using the high-brilliance synchrotron radiation in SPring-8

    International Nuclear Information System (INIS)

    2006-10-01

    The advanced development of catalysts by using the high-brilliance synchrotron radiation in SPring-8 is described: (1) the industrial use of SPring-8, (2) the analytical methods of catalyst using SPring-8 (XAFS, powder X-ray diffraction, thin film X-ray scattering, X-ray imaging, infrared analysis, X-ray fluorescence analysis, and photoelectron spectroscopy etc.), (3) the history of synchrotron radiation and catalyst investigations, (4) the new advanced measuring methods of catalyst using synchrotron radiation (various X-ray spectroscopic methods, and application of XAFS to highly-disperse systems of catalyst), and (5) the new advanced development of catalysts using synchrotron radiation and its applications (motor-car catalysts, light catalysts, fuel cells, nanotechnology, and trace amounts of catalyst in wastes). (M.H.)

  20. Computational model for the tritium inventory management in a nuclear plant

    International Nuclear Information System (INIS)

    Zamfirache, M.; Bornea, A.; Stefanescu, I.; Stefan, L.; Bidica, N.; Vasut, F.; David, C.

    2010-01-01

    Full text: ICIT Rm. Valcea has built an experimental pilot plant having as the main objective the development of a technology for detritiation of heavy water processed in CANDU-type reactors at the nuclear power plant in Cernavoda, Romania. The aspects related to safeguards and safety for such a detritiation installation being of great importance, a complex computational model has been developed. The model allows real-time calculation of tritium inventory in a working installation. The applied detritiation technology is catalyzed isotopic exchange coupled with cryogenic distillation. The computational model was developed as based on the experience obtained in the pilot installation operation. The model uses a set of coefficients specific for isotopic exchange processes. The coefficients were experimentally determined in the pilot installation. The model is included in the monitoring system and uses as input data the parameters acquired in real-time from automation system of the pilot installation. A friendly interface has been created to visualize the final results as data or graphs. (authors)

  1. The generation of efficient supported (Heterogeneous) olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, Robert H

    2013-04-05

    Over the past decade, a new family of homogeneous metathesis catalysts has been developed that will tolerate most organic functionalities as well as water and air. These homogeneous catalysts are finding numerous applications in the pharmaceutical industry as well as in the production of functional polymers. In addition the catalysts are being used to convert seed oils into products that can substitute for those that are now made from petroleum products. Seed oils are unsaturated, contain double bonds, and are a ready source of linear hydrocarbon fragments that are specifically functionalized. To increase the number of applications in the area of biomaterial conversion to petrol chemicals, the activity and efficiency of the catalysts need to be as high as possible. The higher the efficiency of the catalysts, the lower the cost of the conversion and a larger number of practical applications become available. Active supported catalysts were prepared and tested in the conversion of seed oils and other important starting materials. The outcome of the work was successful and the technology has been transferred to a commercial operation to develop viable applications of the discovered systems. A biorefinery that converts seed oils is under construction in Indonesia. The catalysts developed in this study will be considered for the next generation of operations.

  2. 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.

  3. Moessbauer investigations of the Fe-Cu-Mn catalysts for Fischer-Tropsch synthesis

    International Nuclear Information System (INIS)

    Spanu, V.; Filoti, G.; Ilie, I.; Zamfirescu, E.

    1990-01-01

    In the selective process of the syngas conversion to synthetic gasoline a bifunctional catalytic system has to be used. It was obtained by combination a Fischer-Tropsch catalyst with the HZSM-5 zeolite. The phase compositions of the precursor and the fresh catalyst were established as well as the optimum thermal treatment. The catalyst was reduced in pure H 2 or in a H 2 +CO mixture. The influence of the reduction and reaction conditions on the catalyst structure was investigated. (orig.)

  4. Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

    Science.gov (United States)

    Valizadeh, S.; Rasoulifard, M. H.; Dorraji, M. S. Seyed

    2014-11-01

    The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag3PO4 formation. Apparent reaction rate constant (Kapp) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H2O2, Co-M-HAP(II)/H2O2 and M-HAP (I)/UV systems, respectively.

  5. Sustainable Applications of Magnetic Nano-catalysts and Graphitic Carbon Nitrides (presentation)

    Science.gov (United States)

    Homogeneous catalysts, known for chemo-, regio- and enantioselectivity, have better contact with the reactants but the catalyst separation creates barriers. Heterogeneous systems enable better separation although at the cost of reduction in the availability of active sites. Becau...

  6. Superior mercury-free catalysts for acetylene hydrochlorination to VCM. Achieving high productivities and long catalyst life-time

    Energy Technology Data Exchange (ETDEWEB)

    Liebens, A.T.; Piccinini, M. [Solvay S.A., Bruxelles (Belgium)

    2013-11-01

    New mercury-free catalytic systems based on the use of ionic liquids (IL) and noble metals (e.g. Pd, Au) have been evaluated for the hydrochlorination reaction of acetylene to produce Vinyl Chloride Monomer (VCM). Two different approaches have been investigated: gas-liquid homogeneous catalytic systems in the presence of molten IL/Metal and heterogeneous gas-solid ones using solid materials. For the latter case, very positive results have been obtained using SILP-type catalysts (SILP: Supported Ionic Liquid Phase) where IL/Metal were deposited onto a solid mesoporous support. Remarkably, both systems display very high Space Time Yield (STY) and breakthrough life-time stability. No deactivation is observed even after 500 h on stream indicating the strong advantages of these new materials compared to most investigated Au/C supported systems. The development of heterogeneous catalysts was preferred as the scale-up of gas-liquid technology implies important CAPEX investments to convert current plants from gas-solid to gas-liquid equipment. (orig.)

  7. A Comparative Study of Carbon Nanotubes Synthesized from Co/Zn/Al and Fe/Ni/Al Catalyst

    Directory of Open Access Journals (Sweden)

    Ezekiel Dixon Dikio

    2011-01-01

    Full Text Available The catalyst systems Fe/Ni/Al and Co/Zn/Al were synthesized and used in the synthesis of carbon nanotubes. The carbon nanotubes produced were characterized by Field Emission Scanning Electron Microscope (FE-SEM, Energy Dispersive x-ray Spectroscopy (EDS, Raman spectroscopy, Thermogravimetric Analysis (TGA and Transmission Electron Microscope (TEM. A comparison of the morphological profile of the carbon nanotubes produced from these catalysts indicates the catalyst system Fe/Ni/Al to have produced higher quality carbon nanotubes than the catalyst system Co/Zn/Al.

  8. Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt

    1996-01-01

    Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...

  9. Methods and catalysts for making biodiesel from the transesterification and esterification of unrefined oils

    Science.gov (United States)

    Yan, Shuli [Detroit, MI; Salley, Steven O [Grosse Pointe Park, MI; Ng, K Y. Simon [West Bloomfield, MI

    2012-04-24

    A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system according to one aspect of the present disclosure represents a class of zinc and lanthanum oxide heterogeneous catalysts that include different ratios of zinc oxide to lanthanum oxides (Zn:La ratio) ranging from about 10:0 to 0:10. The Zn:La ratio in the catalyst is believed to have an effect on the number and reactivity of Lewis acid and base sites, as well as the transesterification of glycerides, the esterification of fatty acids, and the hydrolysis of glycerides and biodiesel.

  10. Characterization and Regeneration of Pt-Catalysts Deactivated in Municipal Waste Flue Gas

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Kustov, Arkadii; Due-Hansen, Johannes

    2006-01-01

    Severe deactivation was observed for industrially aged catalysts used in waste incineration plants and tested in lab-scale. Possible compounds that cause deactivation of these Pt-based CO oxidation catalysts have been studied. Kinetic observations of industrial and model catalysts showed...... that siloxanes were the most severe catalyst poisons, although acidic sulfur compounds also caused deactivation. Furthermore, a method for on-site regeneration without shutdown of the catalytic flue gas cleaning system has been developed, i.e. an addition of H-2/N-2 gas to the off-gas can completely restore...... the activity of the deactivated catalysts. (c) 2006 Elsevier B.V. All rights reserved....

  11. Gaseous exchange reaction of deuterium between hydrogen and water on hydrophobic catalyst supporting platinum

    International Nuclear Information System (INIS)

    Izawa, Hirozumi; Isomura, Shohei; Nakane, Ryohei.

    1979-01-01

    The deuterium exchange reaction between hydrogen and water in the gas phase where the fed hydrogen gas is saturated with water vapor is studied experimentally by use of the proper hydrophobic catalysts supporting platinum. It is found that the activities of those catalysts for this reaction system are very high compared with the other known ones for the systems in which gas and liquid should coexist on catalyst surfaces, and that the apparent catalytic activity becomes larger as the amount of platinum supported on a catalyst particle increases. By analyses of the data the following informations are obtained. The exchange reaction can be expressed by a first order reversible reaction kinetics. The pore diffusion in the catalyst particles has significant effect on the overall reaction mechanisms. (author)

  12. Hydroformylation of 1-Hexene over Rh/Nano-Oxide Catalysts

    Directory of Open Access Journals (Sweden)

    Sari Suvanto

    2013-03-01

    Full Text Available The effect of nanostructured supports on the activity of Rh catalysts was studied by comparing the catalytic performance of nano- and bulk-oxide supported Rh/ZnO, Rh/SiO2 and Rh/TiO2 systems in 1-hexene hydroformylation. The highest activity with 100% total conversion and 96% yield of aldehydes was obtained with the Rh/nano-ZnO catalyst. The Rh/nano-ZnO catalyst was found to be more stable and active than the corresponding rhodium catalyst supported on bulk ZnO. The favorable morphology of Rh/nano-ZnO particles led to an increased metal content and an increased number of weak acid sites compared to the bulk ZnO supported catalysts. Both these factors favored the improved catalytic performance. Improvements of catalytic properties were obtained also with the nano-SiO2 and nano-TiO2 supports in comparison with the bulk supports. All of the catalysts were characterized by scanning electron microscope (SEM, inductively coupled plasma mass spectrometry (ICP-MS, BET, powder X-ray diffraction (PXRD and NH3- temperature-programmed desorption (TPD.

  13. Influence of hydrogen treatment on SCR catalysts

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    stream, i.e. by in situ treatment of the Pt-catalyst by reductive H2-gas. However, the introduction of H2 gas in the gas stream could also affect other units in the tail pipe gas cleaning system. Of special interest in this study is the effect of hydrogen gas on the performance of the selective catalytic...... reduction (SCR) process, i.e. the catalytic removal of NOx from the flue gas. A series of experiments was conducted to reveal the impact on the NO SCR activity of a industrial DeNOX catalyst (3%V2O5-7%WO3/TiO2) by treatment of H2. Standard conditions were treatment of the SCR catalyst for 60 min with three...... different concentrations of H2 (0-2%) in a 8% O2/N2 mixture, where the SCR activity was measured before and after the hydrogen treatment. The results show that the activity of the SCR catalyst is only negligible affected during exposure to the H2/O2 gas and in all cases it returned reversibly to the initial...

  14. Regeneration of a deactivated USY alkylation catalyst using supercritical isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; David N. Ghompson; Kyle C. Burch

    2005-01-01

    Off-line, in-situ alkylation activity recovery from a completely deactivated solid acid catalyst was examined in a continuous-flow reaction system employing supercritical isobutane. A USY zeolite catalyst was initially deactivated during the liquid phase alkylation of butene with isobutane in a single-pass reactor and then varying amounts of alkylation activity were recovered by passing supercritical isobutane over the catalyst bed at different reactivation conditions. Temperature, pressure and regeneration time were found to play important roles in the supercritical isobutane regeneration process when applied to a completely deactivated USY zeolite alkylation catalyst. Manipulation of the variables that influence solvent strength, diffusivity, surface desorption, hydride transfer rates, and coke aging, strongly influence regeneration effectiveness.

  15. Spent catalyst waste management. A review. Part 1. Developments in hydroprocessing catalyst waste reduction and use

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, M.; Stanislaus, A. [Petroleum Refining Department, Petroleum Research and Studies Center, Kuwait Institute for Scientific Research, P.O. Box 24885, 13109-Safat (Kuwait)

    2008-04-15

    Solid catalysts containing metals, metal oxides or sulfides, which play a key role in the refining of petroleum to clean fuels and many other valuable products, become solid wastes after use. In many refineries, the spent catalysts discarded from hydroprocessing units form a major part of these solid wastes. Disposal of spent hydroprocessing catalysts requires compliance with stringent environmental regulations because of their hazardous nature and toxic chemicals content. Various options such as minimizing spent catalyst waste generation by regeneration and reuse, metals recovery, utilization to produce useful materials and treatment for safe disposal, could be considered to deal with the spent catalyst environmental problem. In this paper, information available in the literature on spent hydroprocessing catalyst waste reduction at source by using improved more active and more stable catalysts, regeneration, rejuvenation and reuse of deactivated catalysts in many cycles, and reusing in other processes are reviewed in detail with focus on recent developments. Available methods for recycling of spent hydroprocessing catalysts by using them as raw materials for the preparation of active new catalysts and many other valuable products are also reviewed. (author)

  16. 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

  17. Supramolecular water oxidation with Ru-bda-based catalysts.

    Science.gov (United States)

    Richmond, Craig J; Matheu, Roc; Poater, Albert; Falivene, Laura; Benet-Buchholz, Jordi; Sala, Xavier; Cavallo, Luigi; Llobet, Antoni

    2014-12-22

    Extremely slow and extremely fast new water oxidation catalysts based on the Ru-bda (bda=2,2'-bipyridine-6,6'-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycles s(-1) , respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system π-stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Origin of Life and the Phosphate Transfer Catalyst

    Science.gov (United States)

    Piast, Radosław W.; Wieczorek, Rafał M.

    2017-03-01

    In this paper, we revisit several issues relevant to origin-of-life research and propose a Phosphate Transfer Catalyst hypothesis that furthers our understanding of some of the key events in prebiotic chemical evolution. In the Phosphate Transfer Catalyst hypothesis, we assume the existence of hypothetical metallopeptides with phosphate transfer activity that use abundant polyphosphates as both substrates and energy sources. Nonspecific catalysis by this phosphate transfer catalyst would provide a variety of different products such as phosphoryl amino acids, nucleosides, polyphosphate nucleotides, nucleic acids, and aminoacylated nucleic acids. Moreover, being an autocatalytic set and metabolic driver at the same time, it could possibly replicate itself and produce a collective system of two polymerases; a nucleic acid able to catalyze peptide bond formation and a peptide able to polymerize nucleic acids. The genetic code starts at first as a system that reduces the energy barrier by bringing substrates (2'/3' aminoacyl-nucleotides) together, an ancestral form of the catalysis performed by modern ribosomes.

  19. Catalytic activity of dual catalysts system based on nano-manganese oxide and cobalt octacyanophthalocyanine toward four-electron reduction of oxygen in alkaline media

    International Nuclear Information System (INIS)

    Zhang, Dun; Chi, Dahe; Okajima, Takeyoshi; Ohsaka, Takeo

    2007-01-01

    The electrocatalysis of the dual functional catalysts system composed of electrolytic nano-manganese oxide (nano-MnOx) and cobalt octacyanophthalocyanine (CoPcCN) toward 4-electron reduction of oxygen (O 2 ) in alkaline media was studied. Nano-MnOx electrodeposited on the CoPcCN monolayer-modified glassy carbon (GC) electrode was clarified as the nano-rods with ca. 10-20 nm diameter by scanning electron microscopy. The peak current for O 2 reduction at the dual catalysts-modified GC electrode increases largely and the peak potential shifts by ca. 160 mV to the positive direction in cyclic voltammograms compared with those obtained at the bare GC electrode. The Koutecky-Levich plots indicate that the O 2 reduction at the dual catalysts-modified GC electrode is an apparent 4-electron process. Collection efficiencies obtained at the dual catalysts-modified GC electrode are much lower than those at the GC electrode and are almost similar to those at the Pt nano-particles modified GC electrode. The obtained results demonstrate that the dual catalysts system possesses a bifuctional catalytic activity for redox-mediating 2-electron reduction of O 2 to HO 2 - by CoPcCN as well as catalyzing the disproportionation of HO 2 - to OH - and O 2 by nano-MnOx, and enables an apparent 4-electron reduction of O 2 at a relatively low overpotential in alkaline media. In addition, it has been found that the cleaning of the dual catalysts-modified electrode by soaking in 0.1 M sulfuric acid solution enhances its catalytic activity toward the reduction of O 2

  20. Hydroprocessing catalysts utilization and regeneration schemes

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    The catalyst reactor inventory represents an important part of the cost of hydroprocessing operation. The selection of a suitable catalyst and reactor is influenced by feedstock properties. Processes ensuring an uninterrupted operation during catalyst addition and withdrawal are preferred for processing high asphaltene and metal content feedstocks. The spent catalyst can be regenerated and returned to the operation if the extent of its deactivation is not high. The regeneration may be performed either in-situ or off-site. The former is suitable for fixed bed reactors whereas the catalyst from ebullated bed reactors must be regenerated off-site. The regeneration of spent catalysts heavily loaded with metals such as V, Ni and Fe may not be economic. Such catalysts may be suitable for metal reclamation. An environmentally safe method for catalyst disposal must be found if neither regeneration nor metal reclamation from spent catalysts can be performed.

  1. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

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

    2012-01-01

    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......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......–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...

  2. 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

  3. Catalyst in alternate energy resources for producing environment friendly clean energy

    International Nuclear Information System (INIS)

    Hussain, S.T.; Atta, M.A.

    1998-01-01

    Carbon monoxide, a by-product of the Chemical Process Industries, is a deadly poisonous gas; if released into the atmosphere causes irreparable damage to the environment. A bimetallic catalyst system Ru: Mn doped with different concentrations of 'K' (Potassium) and supported on high surface area alumina support was prepared by co impregnation method, dispersed and reduced at 450 deg. C under hydrogen flow using a closed reactor system at atmospheric pressure for the utilization of poisonous CO gas to produce environmental friendly clean energy. Fischer Tropsch catalyst, when subjected to CO/hydrogenation, gives methane and other hydrocarbon products. The main purpose of this research work was two fold: 1. The powder catalyst when dispersed/reduced on a high surface area oxide support spreads on the surface of the system in a different orientations and shapes. The particle size of the prepared catalysts ranges from 5.0-25.0 nm. The whole system forms a complicated mixture of numerous particles and hence becomes very complicated to study. The characterisation of these randomly oriented particles having different sizes and shapes is a difficult job. This required sensitive UHV spectroscopic techniques like SSIMS, XPS, EEls, XRD and TEM. Their operations needs strong skills. Hence the first aim was to utilize these techniques for the characterization of the prepared catalysts and to establish the usefulness of these techniques in studying such complicated systems. 2. Since Ru is a very good Fischer Tropsch catalyst for the production of aliphatic hydrocarbons product. Our other aim was to find out whether if by surface modification through additives or by surface reconstructing through chemical treatment, we could alter the path of this CO/hydrogenation reaction to produce potentially important unsaturated/aromatic hydrocarbon products. This would serve our dual purpose in which we could use poisonous CO for useful purpose. Hence 'K' potassium as surface modifier is

  4. Reuse of Hydrotreating Spent Catalyst

    International Nuclear Information System (INIS)

    Habib, A.M.; Menoufy, M.F.; Amhed, S.H.

    2004-01-01

    All hydro treating catalysts used in petroleum refining processes gradually lose activity through coking, poisoning by metal, sulfur or halides or lose surface area from sintering at high process temperatures. Waste hydrotreating catalyst, which have been used in re-refining of waste lube oil at Alexandria Petroleum Company (after 5 years lifetime) compared with the same fresh catalyst were used in the present work. Studies are conducted on partial extraction of the active metals of spent catalyst (Mo and Ni) using three leaching solvents,4% oxidized oxalic acid, 10% aqueous sodium hydroxide and 10% citric acid. The leaching experiments are conducting on the de coked extrude [un crushed] spent catalyst samples. These steps are carried out in order to rejuvenate the spent catalyst to be reused in other reactions. The results indicated that 4% oxidized oxalic acid leaching solution gave total metal removal 45.6 for de coked catalyst samples while NaOH gave 35% and citric acid gave 31.9 % The oxidized leaching agent was the most efficient leaching solvent to facilitate the metal removal, and the rejuvenated catalyst was characterized by the unchanged crystalline phase The rejuvenated catalyst was applied for hydrodesulfurization (HDS) of vacuum gas oil as a feedstock, under different hydrogen pressure 20-80 bar in order to compare its HDS activity

  5. 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...

  6. Radiological safety system based on real-time tritium-in-air monitoring indoors and in effluents

    International Nuclear Information System (INIS)

    Bidica, N.; Sofalca, N; Balteanu, O.; Srefan, I.

    2006-01-01

    Exposure to tritium is an important health hazard in any tritium processing facility so that implementing a real-time tritium monitoring system is necessary for its operation in safety conditions. The tritium processing facility operators need to be informed at any time about the in-air tritium concentration indoors or in the stack effluents, in order to detect immediately any leaks in tritium containments, or any releases inside the buildings or to the environment. This information is very important for adopting if necessary protection measures and correcting actions as quickly as possible. In this paper we describe an improved real-time tritium monitoring system designed for the Heavy Water Detritiation Pilot Plant of National Institute for Cryogenics and Isotopes Separation, Rm. Valcea, Romania. The design of the Radiological Safety System implemented for the ICIT Water Detritiation Pilot Plant is intended to provide the maximum safety level based on the ALARA concept. The main functions of tritium monitoring system are: - monitoring the working areas and gaseous effluents by determination of the tritium-in-air activity concentration; - local and remote data display; - assessing of environment dose equivalent rates and dose equivalents in the working environment (for personnel exposure control and work planning); - assessing the total tritium activity released to the environment through ventilation exhaust stack; - safety functions, i.e., local and remote, locking/unlocking personnel access, process shut-down in emergency conditions and start of the air cleaning systems. With all these features our tritium monitoring system is really a safety system adequate for personnel and environmental protection. (authors)

  7. Studies about the transfer phenomena of tritium from liquid to gaseous phase in a catalyst and ordered packing successive system

    International Nuclear Information System (INIS)

    Bornea, Anisia; Cristescu, Ion; Zamfirache, Marius; Varlam, Carmen

    2002-01-01

    The processes for hydrogen isotope separation are very important for nuclear technology. One of the most important processes for tritium separation, is the catalyst isotope exchange water-hydrogen. In a column of isotope exchange tritium is transferred from liquid phase (tritiated heavy water) in gaseous phase (hydrogen). In the experimental setup, which was used, the column of catalytic isotope exchange is filled with successive layers of catalyst and ordered packing. The catalyst consists of 95.5 wt.% of PTFE, 4.1 wt. % of carbon and 0.40 wt. % of platinum and was made of Raschig rings 10 x 10 x 2 mm. The ordered packing was of B7 type and consists of a phosphor bronze wire mesh of 0.18 x 0.48 mm dimension. We analysed the transfer phenomena of tritium from liquid to gaseous phase, in this system. The mathematical model presented in the paper allowed computing experimental data for testing the catalyst performances. In this way the speed constants which characterized the isotopic exchange on the catalysis bed ks, and the distillation on the ordered packing kd, were expressed as function of experimental concentrations and hydrodynamic conditions. (authors)

  8. Use of ionic liquids as coordination ligands for organometallic catalysts

    Science.gov (United States)

    Li, Zaiwei [Moreno Valley, CA; Tang, Yongchun [Walnut, CA; Cheng,; Jihong, [Arcadia, CA

    2009-11-10

    Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

  9. Effects of particulates, heavy metals and acid gas on the removals of NO and PAHs by V2O5-WO3 catalysts in waste incineration system

    International Nuclear Information System (INIS)

    Chang, Feng-Yim; Chen, Jyh-Cherng; Wey, Ming-Yen; Tsai, Shih-An

    2009-01-01

    This study investigated the activities of prepared and commercial V 2 O 5 -WO 3 catalysts for simultaneous removals of NO and polycyclic aromatic hydrocarbons (PAHs) and the influences of particulates, heavy metals, SO 2 , and HCl on the performances of catalysts. The experiments were carried out in a laboratory-scale waste incineration system equipped with a catalyst reactor. The DREs of PAHs by prepared and commercial V 2 O 5 -WO 3 catalysts were 64% and 72%, respectively. Increasing the particulate concentrations in flue gas suppressed the DRE of PAHs, but increasing the carbon content on surface of catalysts promotes the NO conversions. The DRE of PAHs by the catalysts was significantly decreased by the increased concentrations of heavy metal Cd, but was promoted by high concentration of Pb. The influence level of SO 2 was higher than HCl on the performances of V 2 O 5 -WO 3 catalysts for PAHs removal, but was lower than HCl for NO removal. Prepared and commercial V 2 O 5 -WO 3 catalysts have similar trends on the effects of particulates, heavy metals, SO 2 , and HCl. The results of ESCA analysis reveal that the presences of these pollutants on the surface of catalysts did not change the chemical state of V and W.

  10. Effect of precipitating agent on the catalytic behaviour of precipitated iron catalysts

    International Nuclear Information System (INIS)

    Motjope, T.R.; Dlamini, H.T.; Pollak, H.; Coville, N.J.

    1999-01-01

    Iron precipitated catalysts have been prepared using different precipitating agents (NH 4 OH, K 2 CO 3 ) at different pH values. In situ Moessbauer (MES) study of the reduced catalyst prepared using NH 4 OH revealed the presence of superparamagnetic Fe 2+ , Fe 3+ and magnetically split α-Fe only, whereas the catalyst prepared with K 2 CO 3 also showed an extra magnetic sextuplet of Fe 3 O 4 . For both catalyst systems, in situ MES revealed that during Fischer-Tropsch synthesis α-Fe was converted into ε'-Fe 2,2 C and finally into χ-Fe 2,5 C when the synthesis time was increased. The rate of formation of hydrocarbons was observed to increase with the increase in the degree of carburisation with the NH 4 OH catalyst showing a higher rate of reaction. The K 2 CO 3 catalyst exhibited higher olefin selectivity than the NH 4 OH catalyst under similar pH conditions

  11. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Anthony Marshall [Univ. of California, Berkeley, CA (United States)

    2006-05-20

    In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

  12. Development and Comparison of the Substrate Scope of Pd-Catalysts for the Aerobic Oxidation of Alcohols

    Science.gov (United States)

    Schultz, Mitchell J.; Hamilton, Steven S.; Jensen, David R.; Sigman, Matthew S.

    2009-01-01

    Three catalysts for aerobic oxidation of alcohols are discussed and the effectiveness of each is evaluated for allylic, benzylic, aliphatic, and functionalized alcohols. Additionally, chiral nonracemic substrates as well as chemoselective and diastereoselective oxidations are investigated. In this study, the most convenient system for the Pd-catalyzed aerobic oxidation of alcohols is Pd(OAc)2 in combination with triethylamine. This system functions effectively for the majority of alcohols tested and uses mild conditions (3 to 5 mol % of catalyst, room temperature). Pd(IiPr)(OAc)2(H2O) (1) also successfully oxidizes the majority of alcohols evaluated. This system has the advantage of significantly lowering catalyst loadings but requires higher temperatures (0.1 to 1 mol % of catalyst, 60 °C). A new catalyst is also disclosed, Pd(IiPr)(OPiv)2 (2). This catalyst operates under very mild conditions (1 mol %, room temperature, and air as the O2 source) but with a more limited substrate scope. PMID:15844968

  13. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-03-31

    In this reporting period, a fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of production since the reaction is highly exothermic. Consequently, heavy wax products must be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase FTS. The separation problem is further compounded by catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. Existing pilot-scale equipment was modified to include a filtration test apparatus. After undergoing an extensive plant shakedown period, filtration tests with cross-flow filter modules using simulant FTS wax slurry were conducted. The focus of these early tests was to find adequate mixtures of polyethylene wax to simulate FTS wax. Catalyst particle size analysis techniques were also developed. Initial analyses of the slurry and filter permeate particles will be used by the research team to design improved filter media and cleaning strategies.

  14. 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

  15. Hydroxide catalysts for lignin depolymerization

    Science.gov (United States)

    Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-10-17

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  16. Hydroxide catalysts for lignin depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  17. Development of a Practical Hydrogen Storage System Based on Liquid Organic Hydrogen Carriers and a Homogeneous Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Craig [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Brayton, Daniel [Hawaii Hydrogen Carriers, LLC, Honolulu, HI (United States); Jorgensen, Scott W. [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.; Hou, Peter [General Motors, LLC, Warren, MI (United States). Research and Development Center. Chemical and Material Systems Lab.

    2017-03-24

    The objectives of this project were: 1) optimize a hydrogen storage media based on LOC/homogeneous pincer catalyst (carried out at Hawaii Hydrogen Carriers, LLC) and 2) develop space, mass and energy efficient tank and reactor system to house and release hydrogen from the media (carried out at General Motor Research Center).

  18. Tritium systems for the TITAN reversed-field pinch fusion reactor design

    International Nuclear Information System (INIS)

    Martin, R.C.; Sze, D.K.; Bartlit, J.R.; Gierszewski, P.J.

    1987-01-01

    Tritium systems for the TITAN reversed-field pinch (RFP) fusion reactor study have been designed for two blanket concepts. The TITAN-1 design uses a self-cooled liquid-lithium blanket. The TITAN-2 design uses a self-cooled aqueous-solution blanket, with lithium nitrate dissolved in the water for tritium breeding. Tritium inventory, release, and safety margins are within regulatory limits, at acceptable costs. Major issues for TITAN-1 are plasma-driven permeation, the need for a secondary coolant loop, tritium storage requirements, redundancy in the plasma exhaust system, and minimal isotopic distillation of the exhaust. TITAN-1 fuel cleanup, reprocessing, and air detritiation systems are described in detail

  19. Hydrous titanium oxide-supported catalysts

    International Nuclear Information System (INIS)

    Dosch, R.G.; Stohl, F.V.; Richardson, J.T.

    1990-01-01

    Catalysts were prepared on hydrous titanium oxide (HTO) supports by ion exchange of an active metal for Na + ions incorporated in the HTO support during preparation by reaction with the parent Ti alkoxide. Strong active metal-HTO interactions as a result of the ion exchange reaction can require significantly different conditions for activation as compared to catalysts prepared by more widely used incipient wetness methods. The latter catalysts typically involve conversion or while the HTO catalysts require the alteration of electrostatic bonds between the metal and support with subsequent alteration of the support itself. In this paper, the authors discuss the activation, via sulfidation or reduction, of catalysts consisting of Co, Mo, or Ni-Mo dispersed on HTO supports by ion exchange. Correlations between the activation process and the hydrogenation, hydrodeoxygenation, and hydrodesulfurization activities of the catalysts are presented

  20. Iron Contamination Mechanism and Reaction Performance Research on FCC Catalyst

    Directory of Open Access Journals (Sweden)

    Zhaoyong Liu

    2015-01-01

    Full Text Available FCC (Fluid Catalytic Cracking catalyst iron poisoning would not only influence units’ product slate; when the poisoning is serious, it could also jeopardize FCC catalysts’ fluidization in reaction-regeneration system and further cause bad influences on units’ stable operation. Under catalytic cracking reaction conditions, large amount of iron nanonodules is formed on the seriously iron contaminated catalyst due to exothermic reaction. These nodules intensify the attrition between catalyst particles and generate plenty of fines which severely influence units’ smooth running. A dense layer could be formed on the catalysts’ surface after iron contamination and the dense layer stops reactants to diffuse to inner structures of catalyst. This causes extremely negative effects on catalyst’s heavy oil conversion ability and could greatly cut down gasoline yield while increasing yields of dry gas, coke, and slurry largely. Research shows that catalyst’s reaction performance would be severely deteriorated when iron content in E-cat (equilibrium catalyst exceeds 8000 μg/g.

  1. 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.

  2. Magnetic catalyst bodies

    NARCIS (Netherlands)

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

    1999-01-01

    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

  3. XPS analysis of supported catalysts prepared in water-in-oil microemulsion system

    International Nuclear Information System (INIS)

    Mohd Ambar Yarmo; Wong Hoi Jin; Tan Chew Khim; Anita Ramli; Shahidan Radiman

    2002-01-01

    Catalysts supported on γ-alumina prepared by water-in-oil microemulsion were studied by X-ray photoelectron spectroscopy for comparison with catalysts prepared by wet impregnation. Comparable shifts to higher binding energies indicated a metal-support interaction where metal obtained via microemulsion is very small in size and highly dispersed. The positive binding energy shifts could be explained from a net unit positive charge remaining on the cluster in the photoemission final state in addition to the metallic screening from a redistribution of states within the bands. (Author)

  4. In-line localized monitoring of catalyst activity in selective catalytic NO.sub.x reduction systems

    Science.gov (United States)

    Muzio, Lawrence J [Laguna Niguel, CA; Smith, Randall A [Huntington Beach, CA

    2009-12-22

    Localized catalyst activity in an SCR unit for controlling emissions from a boiler, power plant, or any facility that generates NO.sub.x-containing flue gases is monitored by one or more modules that operate on-line without disrupting the normal operation of the facility. Each module is positioned over a designated lateral area of one of the catalyst beds in the SCR unit, and supplies ammonia, urea, or other suitable reductant to the catalyst in the designated area at a rate that produces an excess of the reductant over NO.sub.x on a molar basis through the designated area. Sampling probes upstream and downstream of the designated area draw samples of the gas stream for NO.sub.x analysis, and the catalyst activity is determined from the difference in NO.sub.x levels between the two probes.

  5. Recovery of Cobalt from leach solution of spent oil Hydrodesulphurization catalyst using a synergistic system consisting of VersaticTM10 and Cyanex®272

    Science.gov (United States)

    Yuliusman; Ramadhan, I. T.; Huda, M.

    2018-03-01

    Catalyst are often used in the petroleum refinery industry, especially cobalt-based catalyst such as CoMoX. Every year, Indonesia’s oil industry produces around 1350 tons of spent hydrodesulphurization catalyst in which cobalt makes up for 7%wt. of them. Cobalt is a non-renewable and highly valuable resource. Taking into account the aforementioned reasons, this research was made to recover cobalt from spent hydrodesulphurization catalyst so that it can be reused by industries needing them. The methods used in the recovery of cobalt from the waste catalyst leach solution are liquid-liquid extraction using a synergistic system of VersaticTM 10 and Cyanex®272. Based on the experiments done using the aforementioned methods and materials, the optimum condition for the extraction process: concentration of VersaticTM 10 of 0.35 M, Cyanex®272 of 0.25 M, temperature of 23-25°C (room temperature), and pH of 6 with an extraction percentage of 98.80% and co-extraction of Ni at 93.51%.

  6. Construction and commissioning of a hydrogen cryogenic distillation system for tritium recovery at ICIT Rm. Valcea

    Energy Technology Data Exchange (ETDEWEB)

    Ana, George, E-mail: george.ana@icsi.ro [Institute for Cryogenic and Isotopic Technologies, Rm. Valcea (Romania); Cristescu, Ion [Karlsruhe Istitute for Technologies, Tritium Laboratory, Eggenstein-Leopoldshaffen (Germany); Draghia, Mirela [ISTECH, Timisoara (Romania); Bucur, Ciprian; Balteanu, Ovidiu; Vijulie, Mihai; Popescu, Gheorghe; Costeanu, Claudiu; Sofilca, Nicolae; Stefan, Iulia; Daramus, Robert; Niculescu, Alina; Oubraham, Anisoara; Spiridon, Ionut; Vasut, Felicia; Moraru, Carmen; Brad, Sebastian [Institute for Cryogenic and Isotopic Technologies, Rm. Valcea (Romania); Pasca, Gheorghe [ISTECH, Timisoara (Romania)

    2016-05-15

    Highlights: • Cryogenic distillation (CD) process is being employed for tritium separation from tritiated hydrogen mixtures. • Process control and safety phylosophy with the detritiation plant from Rm. Vâlcea. • Tests undertaken prior to commissioning of the CD system from Rm. Vâlcea. • Preliminary experiments with the CD system (non-radiological). - Abstract: Cryogenic distillation (CD) of hydrogen in combination with Liquid Phase Catalytic Exchange (LPCE) or Combined Electrolytic Catalytic Exchange (CECE) process is used for tritium removal/recovery from tritiated water. Tritiated water is being obtained after long time operation of CANDU reactors, or in case of ITER mainly by the Detritiation System (DS). The cryogenic distillation system (CDS) used to remove/recover tritium from a hydrogen stream consists of a cascade of cryogenic distillation columns and a refrigeration unit which provides the cooling capacity for the condensers of CD columns. The columns, together with the condensers and the process heat-exchangers are accommodated in a vacuumed cold box. In the particularly case of the ICIT Plant, the cryogenic distillation cascade consists of four columns with diameters between 100–7 mm and it has been designed to process up to 10 mc/h of tritiated deuterium. This paper will present the steps undertaken for construction and commissioning of a pilot plant for tritium removal/recovery by cryogenic distillation of hydrogen. The paper will show besides preliminary data obtained during commissioning, also general characteristics of the plant and its equipments.

  7. A NEW TYPE OF HIGHLY-ACTIVE POLYMER-BOUND RHODIUM HYDROFORMYLATION CATALYST

    NARCIS (Netherlands)

    JONGSMA, T; KIMKES, P; CHALLA, G; VANLEEUWEN, PWNM

    1992-01-01

    A new route of attaching phosphites to a (co)polymer chain is described. These copolymers are used for the preparation of a rhodium phosphite hydroformylation catalyst. The catalytic activity of this polymer-bound system is identical to that of the low molecular weight analogue. The catalysts show a

  8. Supported Catalysts for CO2 Methanation: A Review

    Directory of Open Access Journals (Sweden)

    Patrizia Frontera

    2017-02-01

    Full Text Available CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

  9. Radiation modification of vanadium catalyst for anthracene oxidation

    International Nuclear Information System (INIS)

    Norek, J.; Vymetal, J.; Mucka, V.; Pospisil, M.; Cabicar, J.

    1985-01-01

    Vanadium pentoxide on a suitable carrier is often used as catalyst for the oxidation of anthracene in the gaseous phase to 9,10-anthraquinone. The activity and selectivity of the catalyst may be affected by irradiation. The effects were studied of gamma radiation on the properties of the catalyst where the active system was a V 2 O 5 -KOH-K 2 SO 4 mixture on a Al 2 O 3 +SiO 2 carrier. The 60 Co radiation source had an activity of 185 TBq; the carrier of the catalyst was irradiated at a dose rate of 3.05, 1.98 and 0.084 kGy/h to a total dose of 10 kGy. Irradiation increased the selectivity of the catalyst such that in the oxidation temperature optimum of 300 to 400 degC the yield of 9,10-anthraquinone increased by 4.6 to 4.8 %mol. to roughly 90 %mol.; a significant reduction of the content of acid components (phthalanhydride) in the oxidation product also occurred. This effect remained unchanged for 5 months after irradiation. A reduction of selectivity was observed at lower dose rates only in the temperature range between 400 and 480 degC. (A.K.)

  10. Improved Automotive NO (x) Aftertreatment System: Metal Ammine Complexes as NH3 Source for SCR Using Fe-Containing Zeolite Catalysts

    DEFF Research Database (Denmark)

    Johannessen, Tue; Schmidt, Henning; Frey, Anne Mette

    2009-01-01

    Ammonia storage is a challenge in the selective catalytic reduction of NO (x) in vehicles. We propose a new system, based on metal ammines as the ammonia source. In combination with iron containing zeolites as the SCR catalyst it should be possible to obtain a low temperature system for NO (x...

  11. 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.

  12. Overview of the tritium system of Ignitor

    International Nuclear Information System (INIS)

    Rizzello, C.; Tosti, S.

    2008-01-01

    Among the recent design activities of the Ignitor program, the analysis of the tritium system has been carried out with the aim to describe the main equipments and the operations needed for supplying the deuterium-tritium mixtures and recovering the plasma exhaust. In fact, the tritium system of Ignitor provides for injecting deuterium-tritium mixtures into the vacuum chamber in order to sustain the fusion reaction: furthermore, it generally manages and controls the tritium and the tritiated materials of the machine fuel cycle. Main functions consist of tritium storage and delivery, tritium injection, tritium recovery from plasma exhaust, treatment of the tritiated wastes, detritiation of the contaminated atmospheres, tritium analysis and accountability. In this work an analysis of the designed tritium system of Ignitor is summarized

  13. Comparison of sodium borohydride hydrolysis kinetics on Co-based nanocomposite catalysts

    International Nuclear Information System (INIS)

    Hristov, Georgi; Chorbadzhiyska, Elitsa; Mitov, Mario; Rashkov, Rashko; Hubenova, Yolina

    2011-01-01

    In this study, we compared the results, obtained with several Co-based nanocomposites (CoMnB, CoNiMnB and CoNiMoW) produced by electrodeposition on Ni-foam, as catalysts for the sodium borohydride hydrolysis reaction. Based on the comparative analyses, we propose CoNiMnB electrodeposits as most suitable catalysts for development of Hydrogen-on-Demand (HOD) system, while CoNiMoW ones as potential anodes for Direct Borohydride Fuel Cells (DBFCs). Keywords: Hydrogen-on-Demand (HOD), Nanocomposites, Hydrolysis, Catalyst, Kinetic

  14. Fischer-Tropsch Synthesis over Iron Manganese Catalysts: Effect of Preparation and Operating Conditions on Catalyst Performance

    Directory of Open Access Journals (Sweden)

    Ali A. Mirzaei

    2009-01-01

    molar basis which is the most active catalyst for the conversion of synthesis gas to light olefins. The effects of different promoters and supports with loading of optimum support on the catalytic performance of catalysts are also studied. It was found that the catalyst containing 50%Fe/50%Mn/5 wt.%Al2O3 is an optimum-modified catalyst. The catalytic performance of optimal catalyst has been studied in operation conditions such as a range of reaction temperatures, H2/CO molar feed ratios and a range of total pressures. Characterization of both precursors and calcined catalysts is carried out by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, BET specific surface area and thermal analysis methods such as TGA and DSC.

  15. Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

    International Nuclear Information System (INIS)

    Valizadeh, S.; Rasoulifard, M.H.; Dorraji, M.S. Seyed

    2014-01-01

    Graphical abstract: - Highlights: • Photocatalytic degradation of dye by Ag modified HAP under visible light. • Study of Fenton like degradation of dye by transition metal ions modified HAP. • Comparison of catalytic systems according to Langmuir-Hinshelwood kinetic expression. - Abstract: The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag 3 PO 4 formation. Apparent reaction rate constant (K app ) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H 2 O 2 , Co-M-HAP(II)/H 2 O 2 and M-HAP (I)/UV systems, respectively

  16. Deactivation and regeneration of refinery catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.

    1979-08-01

    A discussion covers the mechanisms of catalyst aging, poisoning, coke deposition, and metals deposition; feedstock pretreatment to extend catalyst life; the effects of operating conditions; the effects of catalyst composition and structure on its stability; nonchemical deactivation processes; and methods of catalyst regeneration, including coke burn-off and solvent extraction.

  17. Part I: A Comparative Thermal Aging Study on the Regenerability of Rh/Al2O3 and Rh/CexOy-ZrO2 as Model Catalysts for Automotive Three Way Catalysts

    Directory of Open Access Journals (Sweden)

    Qinghe Zheng

    2015-10-01

    Full Text Available The rhodium (Rh component in automotive three way catalysts (TWC experiences severe thermal deactivation during fuel shutoff, an engine mode (e.g., at downhill coasting used for enhancing fuel economy. In a subsequent switch to a slightly fuel rich condition, in situ catalyst regeneration is accomplished by reduction with H2 generated through steam reforming catalyzed by Rh0 sites. The present work reports the effects of the two processes on the activity and properties of 0.5% Rh/Al2O3 and 0.5% Rh/CexOy-ZrO2 (CZO as model catalysts for Rh-TWC. A very brief introduction of three way catalysts and system considerations is also given. During simulated fuel shutoff, catalyst deactivation is accelerated with increasing aging temperature from 800 °C to 1050 °C. Rh on a CZO support experiences less deactivation and faster regeneration than Rh on Al2O3. Catalyst characterization techniques including BET surface area, CO chemisorption, TPR, and XPS measurements were applied to examine the roles of metal-support interactions in each catalyst system. For Rh/Al2O3, strong metal-support interactions with the formation of stable rhodium aluminate (Rh(AlO2y complex dominates in fuel shutoff, leading to more difficult catalyst regeneration. For Rh/CZO, Rh sites were partially oxidized to Rh2O3 and were relatively easy to be reduced to active Rh0 during regeneration.

  18. Design of Embedded Metal Catalysts via Reverser Micro-Emulsion System: a Way to Suppress Catalyst Deactivation by Metal Sintering

    KAUST Repository

    Al Mana, Noor

    2016-01-01

    are embedded inside the protecting shell have attracted a lot of researchers working in the field of catalysis owing to their enhanced physical and chemical properties suppress catalyst deactivation. Also, a new active site generated at the interface between

  19. Pre-Conceptual Design for Northstar ⁹⁹Mo Process Tritium Removal System

    Energy Technology Data Exchange (ETDEWEB)

    Nobile, Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reichert, Heidi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hollis, William Kirk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taylor, Craig Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gordon, John Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    In this report we describe a preliminary concept for a Tritium Removal System (TRS) to remove tritium that is generated in the ⁹⁹Mo production process. Preliminary calculations have been performed to evaluate an approximate size for the system. The concept described utilizes well-established detritiation technology based on catalytic oxidation of tritium and tritiated hydrocarbons to water in a high temperature (400 °C) reactor and capture of water in a molecular sieve bed. The TRS concept involves use of a single system that would cycle through each of the seven online target systems and remove tritium that has been accumulated after one week’s run time. The TRS would perform cleanup operations on each target system for a period of approximately 24 hours. This would occur while the system is still online and just prior to target replacement, so tritium levels would at their minimum values for target replacement. In the concept, during normal operation a small fraction (1%) of the helium recirculating in the system would be diverted through the TRS and returned to the flow loop. With this approach sufficient levels of detritiation can be accomplished in a 24 hour period. In the study it was found that because of the need to maintain low oxygen levels in the system (<100 ppm) this increases the size of the catalytic reactor. As a result of this finding, consideration should be given to other methods for removing tritium from the system. Other methods such as catalytic exchange of tritium with an unsaturated organic compound and subsequent trapping on activated carbon or molecular sieve could offer advantages of reducing reactor size and operation at lower reactor temperature. However the most significant advantage of such an approach would be the ability to operate in very low oxygen environments, which would eliminate any concerns for oxidation of the target.

  20. Metal Phosphate-Supported Pt Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Xiaoshuang Qian

    2014-12-01

    Full Text Available Oxides (such as SiO2, TiO2, ZrO2, Al2O3, Fe2O3, CeO2 have often been used to prepare supported Pt catalysts for CO oxidation and other reactions, whereas metal phosphate-supported Pt catalysts for CO oxidation were rarely reported. Metal phosphates are a family of metal salts with high thermal stability and acid-base properties. Hydroxyapatite (Ca10(PO46(OH2, denoted as Ca-P-O here also has rich hydroxyls. Here we report a series of metal phosphate-supported Pt (Pt/M-P-O, M = Mg, Al, Ca, Fe, Co, Zn, La catalysts for CO oxidation. Pt/Ca-P-O shows the highest activity. Relevant characterization was conducted using N2 adsorption-desorption, inductively coupled plasma (ICP atomic emission spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, CO2 temperature-programmed desorption (CO2-TPD, X-ray photoelectron spectroscopy (XPS, and H2 temperature-programmed reduction (H2-TPR. This work furnishes a new catalyst system for CO oxidation and other possible reactions.

  1. Transesterification of jatropha oil with methanol over Mg–Zn mixed metal oxide catalysts

    International Nuclear Information System (INIS)

    Lee, H.V.; Taufiq-Yap, Y.H.; Hussein, M.Z.; Yunus, R.

    2013-01-01

    A design was developed for the transesterification reaction of non-edible Jatropha Curcas oil using a heterogeneous catalysis system to replace the use of a homogeneous catalytic reaction. Investigations were conducted on solid MgO–ZnO mixed metal oxide catalyst bases with different atomic ratios of magnesium to zinc (Mg/Zn). These catalysts were characterized by BET (Brunauer–Emmer–Teller) surface area analysis, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), and the alkalinity of the catalysts was studied by Temperature Programmed Desorption of carbon dioxide (TPD-CO 2 ). The physicochemical properties of the MgO–ZnO binary system were superior to those of the individual bulk oxides of MgO and ZnO. In addition, the formation of a binary system between MgO and ZnO established an effective method for transesterification processes. In this study, the effects of stoichiometric composition and surface characteristics on the transesterification activity of MgO–ZnO were investigated. The catalysts exhibited high catalytic activity (∼80%) with reliable reusability for biodiesel production. -- Highlights: ► Transesterification reaction of non-edible jatropha oil using solid base catalyst. ► MgO–ZnO binary system showed superior effect than the individual MgO and ZnO. ► More than 80% of FAME yield was achieved under mild condition. ► MgO–ZnO catalyst showed reliable reusability throughout 5 runs. ► Fuel properties of prepared biodiesel were complying with the biodiesel standards.

  2. Oxidative desulfurization of synthetic diesel using supported catalysts. Part 3. Support effect on vanadium-based catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cedeno-Caero, Luis; Gomez-Bernal, Hilda; Fraustro-Cuevas, Adriana; Guerra-Gomez, Hector D.; Cuevas-Garcia, Rogelio [UNICAT, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria 04510, Mexico D.F. (Mexico)

    2008-04-15

    Oxidesulfurization (ODS) of benzothiophenic compounds prevailing in diesel was conducted with hydrogen peroxide in presence of various catalysts, using a model diesel and actual diesel fuel. ODS activities of dibenzothiophenes (DBTs) in hexadecane for a series of V{sub 2}O{sub 5} catalysts supported on alumina, titania, ceria, niobia and silica, were evaluated. Results show that the oxidation activity of DBTs depends on the support used. It was observed that the sulfone yield is not proportional to textural properties or V content. For all catalysts, ODS of benzothiophene (BT), dibenzothiophene (DBT), 4-methyl dibenzothiophene (4-MDBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) decreased in the following order: DBT > 4-MDBT > 4,6-DMDBT > BT. This trend does not depend on the catalyst used or the textural properties of the catalysts and supports. In presence of indole ODS activities diminish, except with catalysts supported on alumina-titania mixed oxide, whereas with V{sub 2}O{sub 5}/TiO{sub 2} catalyst the performance is the highest. ODS of Mexican diesel fuel was carried out in presence of this catalyst and S level was diminished in about 99%. (author)

  3. Reduction and Analysis of Low Temperature Shift Heterogeneous Catalyst for Water Gas Reaction in Ammonia Production

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2013-09-01

    Full Text Available In order to obtain additional quantities of hydrogen after the reforming reactions of natural gas and protect the ammonia synthesis catalyst, it is crucial to achieve and maintain maximum possible activity, selectivity and stability of the low temperature shift catalyst for conversion of water gas reaction during its lifetime. Whereas the heterogeneous catalyst comes in oxidized form, it is of the utmost importance to conduct the reduction procedure properly. The proper reduction procedure and continuous analysis of its performance would ensure the required activity, selectivity and stability throughout the catalyst’s service time. For the proper reduction procedure ofthe low temperature shift catalyst, in addition to process equipment, also necessary is a reliable and realistic system for temperature measurements, which will be effective for monitoring the exothermal temperature curves through all catalyst bed layers. For efficiency evaluation of low shift temperature catalyst reduction and its optimization, it is necessary to determine at regular time intervals the temperature approach to equilibrium and temperature profiles of individual layers by means of "S" and "die off" temperature exothermal curves. Based on the obtained data, the optimum inlet temperature could be determined, in order to maximally extend the service life of the heterogeneous catalyst as much as possible, and achieve the optimum equilibrium for conversion of the water gas. This paper presents the methodology for in situ reduction of the low temperature shift heterogeneous catalyst and the developed system for monitoring its individual layers to achieve the minimum possible content of carbon monoxide at the exit of the reactor. The developed system for temperature monitoring through heterogeneous catalyst layers provides the proper procedure for reduction and adjustment of optimum process working conditions for the catalyst by the continuous increase of reactor inlet

  4. Reduce NOx Emissions by Adsorber-Reduction Catalyst on Lean Burn Gasoline Engine

    Directory of Open Access Journals (Sweden)

    Dongpeng Yue

    2013-09-01

    Full Text Available The effect of a new catalyst system composed of traditional three way catalyst converter and adsorber-reduction catalysis converter on the emission characteristics and BSFC (Breake Specific Fuel Consumption- BSFCof a lean burn gasoline engine operated were investigated in this paper under different schemes of catalyst converter arrangement and different speeds and loads. The results show that the position of Three Way Catalyst is before the NOx adsorber Catalyst was the best scheme of catalyst converter arrangement. Which has the highest converter efficiency of reduction NOx emission in lean burn gasoline engine. The effects of speed on the exhaust emission and BSFC were also related to the ratio of lean burn time to rich burn time and the absolute value of both time of the adsorber-reduction catalyst converter. The load of the engine was the main influential factor to the exhaust emission characteristics and BSFC of lean burn gasoline engine, and the more load of the engine was, the more NOx emission , the less NOx conversion rate (CNOx and the better BSFC were.

  5. Methanol Steam Reforming Promoted by Molten Salt-Modified Platinum on Alumina Catalysts

    Science.gov (United States)

    Kusche, Matthias; Agel, Friederike; Ní Bhriain, Nollaig; Kaftan, Andre; Laurin, Mathias; Libuda, Jörg; Wasserscheid, Peter

    2014-01-01

    We herein describe a straight forward procedure to increase the performance of platinum-on-alumina catalysts in methanol steam reforming by applying an alkali hydroxide coating according to the “solid catalyst with ionic liquid layer” (SCILL) approach. We demonstrate by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed desorption (TPD) studies that potassium doping plays an important role in the catalyst activation. Moreover, the hygroscopic nature and the basicity of the salt modification contribute to the considerable enhancement in catalytic performance. During reaction, a partly liquid film of alkali hydroxides/carbonates forms on the catalyst/alumina surface, thus significantly enhancing the availability of water at the catalytically active sites. Too high catalyst pore fillings with salt introduce a considerable mass transfer barrier into the system as indicated by kinetic studies. Thus, the optimum interplay between beneficial catalyst modification and detrimental mass transfer effects had to be identified and was found on the applied platinum-on-alumina catalyst at KOH loadings around 7.5 mass %. PMID:25124120

  6. Isotope exchange in oxide-containing catalyst

    Science.gov (United States)

    Brown, Kenneth G. (Inventor); Upchurch, Billy T. (Inventor); Hess, Robert V. (Inventor); Miller, Irvin M. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Hoyt, Ronald F. (Inventor)

    1989-01-01

    A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

  7. Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system.

    Science.gov (United States)

    Torella, Joseph P; Gagliardi, Christopher J; Chen, Janice S; Bediako, D Kwabena; Colón, Brendan; Way, Jeffery C; Silver, Pamela A; Nocera, Daniel G

    2015-02-24

    Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations.

  8. Efficient solar-to-fuels production from a hybrid microbial–water-splitting catalyst system

    Science.gov (United States)

    Torella, Joseph P.; Gagliardi, Christopher J.; Chen, Janice S.; Bediako, D. Kwabena; Colón, Brendan; Way, Jeffery C.; Silver, Pamela A.; Nocera, Daniel G.

    2015-01-01

    Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations. PMID:25675518

  9. Bifunctional cobalt F-T catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.G.; Coughlin, P.K.; Yang, C.L.; Rabo, J.A.

    1986-03-01

    Results on the catalytic screening of Fischer-Tropsch catalysts containing shape selective components are reported. Catalysts consist of promoted cobalt intimately contacted with Union Carbide molecular sieves and were tested using a Berty type internally recycled reactor. Methods of preparation, promoters and shape selective components were varied and aimed at improving catalyst performance. Catalysts were developed demonstrating high C/sub 5/ + yields with high olefin content and low methane production while maintaining stability under both low and high H/sub 2/:CO ratio conditions.

  10. 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...

  11. Catalyst support effects on hydrogen spillover

    Science.gov (United States)

    Karim, Waiz; Spreafico, Clelia; Kleibert, Armin; Gobrecht, Jens; Vandevondele, Joost; Ekinci, Yasin; van Bokhoven, Jeroen A.

    2017-01-01

    Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. The phenomenon has been much studied and its occurrence on reducible supports such as titanium oxide is established, yet questions remain about whether hydrogen spillover can take place on nonreducible supports such as aluminium oxide. Here we use the enhanced precision of top-down nanofabrication to prepare controlled and precisely tunable model systems that allow us to quantify the efficiency and spatial extent of hydrogen spillover on both reducible and nonreducible supports. We place multiple pairs of iron oxide and platinum nanoparticles on titanium oxide and aluminium oxide supports, varying the distance between the pairs from zero to 45 nanometres with a precision of one nanometre. We then observe the extent of the reduction of the iron oxide particles by hydrogen atoms generated on the platinum using single-particle in situ X-ray absorption spectromicroscopy applied simultaneously to all particle pairs. The data, in conjunction with density functional theory calculations, reveal fast hydrogen spillover on titanium oxide that reduces remote iron oxide nanoparticles via coupled proton-electron transfer. In contrast, spillover on aluminium oxide is mediated by three-coordinated aluminium centres that also interact with water and that give rise to hydrogen mobility competing with hydrogen desorption; this results in hydrogen spillover about ten orders of magnitude slower than on titanium oxide and restricted to very short distances from the platinum particle. We anticipate that these observations will improve our understanding of hydrogen storage and catalytic reactions involving hydrogen, and that our approach to creating and probing model catalyst systems will provide opportunities for studying the origin of synergistic effects in supported catalysts that combine multiple functionalities.

  12. Oxygen-reducing catalyst layer

    Science.gov (United States)

    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.

  13. Practical, economical, and eco-friendly starch-supported palladium catalyst for Suzuki coupling reactions.

    Science.gov (United States)

    Baran, Talat

    2017-06-15

    In catalytic systems, the support materials need to be both eco friendly and low cost as well as having high thermal and chemical stability. In this paper, a novel starch supported palladium catalyst, which had these outstanding properties, was designed and its catalytic activity was evaluated in a Suzuki coupling reaction under microwave heating with solvent-free and mild reaction conditions. The starch supported catalyst gave remarkable reaction yields after only 5min as a result of the coupling reaction of the phenyl boronic acid with 23 different substrates, which are bearing aril bromide, iodide, and chloride. The longevity of the catalyst was also investigated, and the catalyst could be reused for 10 runs. The starch supported Pd(II) catalyst yielded remarkable TON (up to 25,000) and TOF (up to 312,500) values by using a simple, fast and eco-friendly method. In addition, the catalytic performance of the catalyst was tested against different commercial palladium catalysts, and the green starch supported catalyst had excellent selectivity. The catalytic tests showed that the novel starch based palladium catalyst proved to be an economical and practical catalyst for the synthesis of biaryl compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. 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

  15. POLYETHYLENEIMINE (PEI ON SILICA AS CATALYST IN KNOEVENAGEL AND MICHAEL REACTIONS

    Directory of Open Access Journals (Sweden)

    FATIHA ZAOUI

    2017-03-01

    Full Text Available After the synthesis of polyethylenimine supported on silica, it has been used as a new and efficient catalyst in Knoevenagel and Michael condensations. The presence of the polyethylenimine in the catalytic system together with silica displays an acido-basic character allows a better catalytic activity in the condensations. Carried out under microwave irradiation, without organic solvent and during short time, the syntheses are respectful towards green chemistry. The solid catalyst can be easily reused. This catalyst has the acido-basic character at the same time.

  16. Development of the ELEX process for tritium separation at reprocessing plants

    International Nuclear Information System (INIS)

    Bruggeman, A.; Meynendonckx, L.; Parmentier, C.; Goossens, W.R.A.; Baetsle, L.H.

    1985-01-01

    The ELEX process for isotopic enrichment and separation of tritium from aqueous reprocessing effluents is described. After the development of an appropriate hydrophobic catalyst and the study of the separate constituent steps of the ELEX process, an integrated bench-scale installation with a detritiation capacity of 10 mol water per hour was constructed. It comprises essentially a 1.5 kW electrolyser and two 2 cm diameter by 3 m high exchange columns. In this mini-pilot the ELEX process was successfully demonstrated by detritiating more than 1000 dm 3 water containing up to 100 mCi tritium per dm 3 , which is the feed concentration expected for application of the process in a reprocessing plant. The process decontamination factor was always larger than 100 and the overall tritium balance could be kept within the experimental errors of the various measurements. Depending on the duration of the runs, the volume reduction factor was between 10 and 15, but this factor will become much higher when the present electrolyser will be replaced by the low-volume one now under construction at S.C.K./C.E.N. The technical availability of the mini-pilot amounted to 99% or more for the last experiments. During the nearly 6000 hours of operation there were no tritium contamination problems. At present the construction of a 280 mol.h -1 or 0.12 m 3 H 2 O (HTO) per day pilot detritiation installation nears completion. In this unit, which will have a total tritium inventory of maximum 1000 Ci, the ELEX process will be demonstrated with a volume reduction factor of 100 and a process decontamination factor of 100. Again the feed concentration will be 100 Ci tritium per m 3 . In the future this installation will be supplemented with a pre-treatment unit for the removal of fission products, organics and nitric acid

  17. Catalysts for cleaner combustion of coal, wood and briquettes sulfur dioxide reduction options for low emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.V. [Global Environmental Solutions, Inc., Morton Grove, IL (United States)

    1995-12-31

    Coal fired, low emission sources are a major factor in the air quality problems facing eastern European cities. These sources include: stoker-fired boilers which feed district heating systems and also meet local industrial steam demand, hand-fired boilers which provide heat for one building or a small group of buildings, and masonary tile stoves which heat individual rooms. Global Environmental Systems is marketing through Global Environmental Systems of Polane, Inc. catalysts to improve the combustion of coal, wood or fuel oils in these combustion systems. PCCL-II Combustion Catalysts promotes more complete combustion, reduces or eliminates slag formations, soot, corrosion and some air pollution emissions and is especially effective on high sulfur-high vanadium residual oils. Glo-Klen is a semi-dry powder continuous acting catalyst that is injected directly into the furnace of boilers by operating personnel. It is a multi-purpose catalyst that is a furnace combustion catalyst that saves fuel by increasing combustion efficiency, a cleaner of heat transfer surfaces that saves additional fuel by increasing the absorption of heat, a corrosion-inhibiting catalyst that reduces costly corrosion damage and an air pollution reducing catalyst that reduces air pollution type stack emissions. The reduction of sulfur dioxides from coal or oil-fired boilers of the hand fired stoker design and larger, can be controlled by the induction of the Glo-Klen combustion catalyst and either hydrated lime or pulverized limestone.

  18. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    Science.gov (United States)

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Metal catalysts fight back

    OpenAIRE

    George Marsh

    1998-01-01

    In recent years organometallic catalysts, especially metallocenes, have been a major focus of attention in terms of polymerisation chemistry. But the news earlier this year of a family of iron-based catalysts able to rival the effectiveness of both conventional and metallocene catalysts in the polymerisation of ethylene has excited the plastics industry. Because of the impact of this discovery and its potential as a route to lower-priced commodity plastics in the future, it may be useful at t...

  20. Rejuvenation of the SCR catalyst at Mehrum

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Y.; Inatsume, Y.; Morita, I.; Kato, Y.; Yokoyama, K.; Ito, K. [Babcock Hitachi K.K., Kure-shi, Hiroshima-ken (Japan)

    2004-07-01

    Babcock Hitachi K.K. (BHK) received the contract of the rejuvenation of the SCR catalyst at the 750 MW coal-fired Mehrum Power Station (in Hohenhameln, Germany) in March 2003. The contractual coverage was 160 m{sup 3} of the entire catalyst layer. The catalyst, which had been in operation for 16 years since 1987, was originally supplied by BHK. The rejuvenation process developed for the Mehrum project consisted of two major steps: the first is to dust off the catalyst and remove the catalyst poison, and the second step is to add active material to enhance the catalyst activity. The catalyst must be dried after each washing. In order to minimize transportation cost and time, the rejuvenation work was done at the Mehrum station site. The scope of the rejuvenation work was shared between the owner and BHK. It took about one and a half months to complete the (total) on-site rejuvenation worked. The performance of the rejuvenated catalyst was superior to show the same level of activity as the unused catalyst and maintain the same SO{sub 2} conversion rate as the spent catalyst. This paper gives the details of the spent coal-fired SCR catalyst rejuvenation work. 13 figs., 1 tab.

  1. Productions of palm oil bio diesel whit heterogeneous basic catalysts compared to conventional homogeneous catalysts

    International Nuclear Information System (INIS)

    Rios, Luis A; Franco C, Alexander; Zuleta S, Ernesto

    2009-01-01

    The conventional process to produce biodiesel involves the presence of homogeneous basic catalysts. However, these catalysts have disadvantages associated to the need of purification steps, which increase the cost of the final product and generate pollution problems caused by the effluents. This paper compares different homogeneous and heterogeneous catalysts for the biodiesel production from palm oil. For this, heterogeneous catalysts supported on alumina were prepared and characterized by nitrogen adsorption, scanning electron microscopy, energy dispersive X ray spectroscopy and X ray diffraction. Transesterification of palm oil with methanol was accomplished at 60 celsius degrade and one hour, varying methanol/oil ratio, the type of catalyst and its concentration. Yields of the reaction and purity of the so obtained biodiesel were evaluated. Comparing the catalysts performance, based on the amount, was found that sodium methoxide (CH 3 ONa) and potassium carbonate supported on alumina (K 2 CO 3 /Al 2 O 3 ) were the catalysts that give the higher purity of biodiesel (96.8 and 95.85% respectively). When was determined the active site quality, by dividing the performance by each mole of active sites, it was found that calcined Na 2 SO 4 /Al 2 O 3 has the most active sites.

  2. Amphiphilic phase-transforming catalysts for transesterification of triglycerides

    Science.gov (United States)

    Nawaratna, Gayan Ivantha

    Heterogeneous catalytic reactions that involve immiscible liquid-phase reactants are challenging to conduct due to limitations associated with mass transport. Nevertheless, there are numerous reactions such as esterification, transesterification, etherification, and hydrolysis where two immiscible liquid reactants (such as polar and non-polar liquids) need to be brought into contact with a catalyst. With the intention of alleviating mass transport issues associated with such systems but affording the ability to separate the catalyst once the reaction is complete, the overall goal of this study is geared toward developing a catalyst that has emulsification properties as well as the ability to phase-transfer (from liquid-phase to solid-phase) while the reaction is ongoing and evaluating the effectiveness of such a catalytic process in a practical reaction. To elucidate this concept, the transesterification reaction was selected. Metal-alkoxides that possess acidic and basic properties (to catalyze the reaction), amphiphilic properties (to stabilize the alcohol/oil emulsion) and that can undergo condensation polymerization when heated (to separate as a solid subsequent to the completion of the reaction) were used to test the concept. Studies included elucidating the effect of metal sites and alkoxide sites and their concentration effects on transesterification reaction, effect of various metal alkoxide groups on the phase stability of the reactant system, and kinetic effects of the reaction system. The studies revealed that several transition-metal alkoxides, especially, titanium and yttrium based, responded positively to this reaction system. These alkoxides were able to be added to the reaction medium in liquid phase and were able to stabilize the alcohol/oil system. The alkoxides were selective to the transesterification reaction giving a range of ester yields (depending on the catalyst used). It was also observed that transition-metal alkoxides were able to be

  3. Toluene degradation by non-thermal plasma combined with a ferroelectric catalyst.

    Science.gov (United States)

    Liang, Wen-Jun; Ma, Lin; Liu, Huan; Li, Jian

    2013-08-01

    Degradation of toluene in a gas by non-thermal plasma with a ferroelectric catalyst was studied at normal temperature and atmospheric pressure. Spontaneous polarization material (BaTiO3) and photocatalyst (TiO2) were added into plasma system simultively. Toluene degradation efficiency and specific energy density during the discharge process were investigated. Furthermore, byproducts and degradation mechanisms of toluene were also investigated. The toluene degradation efficiency increased when non-thermal plasma technology was combined with the catalyst. The toluene degradation efficiencies of the different catalysts tested were in the following order: BaTiO3/TiO2>BaTiO3>TiO2>no catalyst. A mass ratio of 2.38:1 was optimum for the BaTiO3 and TiO2 catalyst. The outlet gas was analyzed by gas chromatography and Fourier transform infrared spectroscopy, and the main compounds detected were CO2, H2O, O3 and benzene ring derivatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Novel metalloporphyrin catalysts for the oxidation of hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Showalter, M.C.; Nenoff, T.M.; Shelnutt, J.A.

    1996-11-01

    Work was done for developing biomimetic oxidation catalysts. Two classes of metalloporphyrin catalysts were studied. The first class of catalysts studied were a novel series of highly substituted metalloporphyrins, the fluorinated iron dodecaphenylporphyrins. These homogeneous metalloporphyrin catalysts were screened for activity as catalysts in the oxidation of hydrocarbons by dioxygen. Results are discussed with respect to catalyst structural features. The second type of catalysts studied were heterogeneous catalysts consisting of metalloporphyrins applied to inorganic supports. Preliminary catalytic testing results with these materials are presented.

  5. Assessment of the cryogenic distillation system in Cernavoda tritium removal facility

    International Nuclear Information System (INIS)

    Pasca, Gheorghe; Draghia, Mirela; Porcariu, Florina; Ana, George

    2010-01-01

    Full text: This paper aims at presenting an assessment of the Cryogenic Distillation system (CD) in the Cernavoda Tritium Removal Facility (CTRF). The cryogenic distillation system is one of the key components of the CTRF which comprises other systems as: the liquid phase catalytic exchange system, designed to transfer tritium from heavy water to a deuterium stream to be fed into the CD system; the atmosphere detritiation system; the tritium recovery system; the tritium/hydrogen monitoring system; the central interlocking system; the tritium extraction and storage system. Thus, the need to build a tritium separation and recovery system results from economic opportunities offered both by heavy water reuse and tritium production, but, at the same time, it offers an alternative for the storage of tritiated heavy water as radioactive waste. (authors)

  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...... 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...

  7. Regeneration of Pt-catalysts deactivated in municipal waste flue gas with H2/N2 and the effect of regeneration step on the SCR catalyst

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Rasmussen, Søren Birk; Kustov, Arkadii

    Municipal waste flue gas was previously found to deactivate the Pt-based CO oxidation catalyst severely. In the specific case studied, siloxanes were found to cause the deactivation. An on-site method for complete regeneration of the catalyst activity was found without shutdown of the flue gas...... stream, i.e. by in situ treatment of the Pt-catalyst by reductive H2-gas. However, introduction of H2 gas in the gas stream could also affect other units in the tail pipe gas cleaning system. Of special interest here, is the effect of hydrogen gas on the performance of the deNOx + SCR catalytic process...

  8. Development status of the cryogenic distillation system in Cernavoda Tritium Removal Facility

    International Nuclear Information System (INIS)

    Draghia, Mirela; Ana, George; Pasca, Gheorghe; Porcariu, Florina

    2009-01-01

    Full text: The reference design technology for the heavy water detritiation plant of Cernavoda CANDU station is based on combination of Liquid Phase Catalytic Exchange (LPCE) and Cryogenic Distillation (CD) processes. Based on this technology, tritium is transferred from the heavy water to a deuterium stream in the catalyzed isotopic exchange process, LPCE, followed by a final enrichment within the cryogenic distillation cascade. The final step is the tritium storage on metallic hydride. The basic function of the Cryogenic Distillation System (CDS) is the separation of tritium from the tritiated deuterium coming from the LPCE column in the following conditions: - the final product has to be tritium with a concentration of at least 99%; - it must be provided a detritiation factor of at least 100 (the ration between the tritium concentration in the deuterium stream fed to the CD system and the tritium concentration in the returned stream to the LPCE); - the deuterium must be enriched up to 99.995%, by removing the protium; - provisions for safe discharge of the entire inventory of the CD cascade into buffer vessels shall be implemented. To summarize, the present status of the project consists of technical documentation for all the components of CDS, including the P and ID (Pipping and Instrumentation Diagram), preliminary data sheets, technical specifications, drawings for the major components as the buffer vessels, coldbox, etc, and 3D models as well for almost all the components. (authors)

  9. 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)

  10. Edge termination of MoS2 and CoMoS catalyst particles

    DEFF Research Database (Denmark)

    Byskov, Line Sjolte; Nørskov, Jens Kehlet; Clausen, B. S.

    2000-01-01

    The edge termination of MoS2 and CoMoS catalyst particles is studied by density functional calculations. We show that for structures without vacancies Mo-terminated edges have the lowest edge energies. Creation of vacancies, which are believed to be active sites in these catalyst systems, leads...

  11. High Throughput In Situ XAFS Screening of Catalysts

    International Nuclear Information System (INIS)

    Tsapatsaris, Nikolaos; Beesley, Angela M.; Weiher, Norbert; Tatton, Helen; Schroeder, Sven L. M.; Dent, Andy J.; Mosselmans, Frederick J. W.; Tromp, Moniek; Russu, Sergio; Evans, John; Harvey, Ian; Hayama, Shu

    2007-01-01

    We outline and demonstrate the feasibility of high-throughput (HT) in situ XAFS for synchrotron radiation studies. An XAS data acquisition and control system for the analysis of dynamic materials libraries under control of temperature and gaseous environments has been developed. The system is compatible with the 96-well industry standard and coupled to multi-stream quadrupole mass spectrometry (QMS) analysis of reactor effluents. An automated analytical workflow generates data quickly compared to traditional individual spectrum acquisition and analyses them in quasi-real time using an HT data analysis tool based on IFFEFIT. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on γ-Al2O3, and for the in situ characterization of Au catalysts supported on Al2O3 and TiO2

  12. 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

    with compositions 25Fe75Ni and 50Fe50Ni showed significantly better activity and in some cases also a higher selectivity to methane compared with the traditional monometallic Ni and Fe catalysts. A catalyst with composition 25Fe75Ni was found to be the most active in CO hydrogenation for the MgAl2O4 support at low...... metal loadings. At high metal concentrations, the maximum for the methanation activity was found for catalysts with composition 50Ni50Fe both on the MgAl2O4 and Al2O3 supports. This difference can be attributed to a higher reducibility of the constituting metals with increasing metal concentration......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. Here...

  13. Effect of aluminum alkyls on a homogeneous and silica-supported phenoxy-imine titanium catalyst for ethylene trimerization

    NARCIS (Netherlands)

    Karbach, Fabian F.; Severn, John R.; Duchateau, Robbert

    A phenoxy-imine titanium catalyst (FI-catalyst) for selective ethylene trimerization was immobilized on methyl aluminoxane (MAO) pretreated silica and its activity and selectivity was compared with that of the corresponding homogeneous catalyst system. The homogeneous and heterogeneous ethylene

  14. Separation of Hydridocarbonyltris(triphenylphosphine) Rhodium (I) Catalyst Using Solvent Resistant Nano filtration Membrane

    International Nuclear Information System (INIS)

    Razak, N.S.A.; Hilmi Mukhtar; Maizatul, S. Shaharun; Mohd, F. Taha

    2013-01-01

    An investigation was conducted into the nano filtration of rhodium tris(triphenyl-phosphine) [HRh(CO)(PPh3)3] catalyst used in the hydroformylation of olefins. The large size of the catalyst (>400 Da) - relative to other components of the reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (STARMEMTM 122 and STARMEMTM 240) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. The morphology of the membrane was studied by field emission scanning electron microscopy (FESEM). The solvent flux and membrane rejection of HRh(CO)(PPh3)3 was then determined for the catalyst-solvent-membrane combination in a dead-end pressure cell. Good HRh(CO)(PPh3)3 rejection (>0.93) coupled with good solvent fluxes (>72 L/ m 2 h 1 at 2.0 MPa) were obtained in one of the systems tested. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting the solvent flux. (author)

  15. 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.

  16. Thioetherification of chloroheteroarenes: a binuclear catalyst promotes wide scope and high functional-group tolerance.

    Science.gov (United States)

    Platon, Mélanie; Wijaya, Novi; Rampazzi, Vincent; Cui, Luchao; Rousselin, Yoann; Saeys, Mark; Hierso, Jean-Cyrille

    2014-09-22

    A constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six- and five-membered 2-chloroheteroarenes (i.e., functionalized pyridine, pyrazine, quinoline, pyrimidine, furane, and thiazole) and 3-bromoheteroarenes (i.e., pyridine and furane). Electron-rich congested thiophenols and fluorinated thiophenols are also suitable partners. The coupling of unprotected amino-2-chloropyridines with thiophenol and the successful employment of synthetically valuable chlorothiophenols are described with the same catalyst system. DFT studies attribute the high performance of this binuclear palladium catalyst to the decreased stability of thiolate-containing resting states. Palladium loading was as low as 0.2 mol %, which is important for industrial application and is a step forward in solving catalyst activation/deactivation problems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. 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.

  18. Enhanced activity of Pt/CNTs anode catalyst for direct methanol fuel cells using Ni2P as co-catalyst

    Science.gov (United States)

    Li, Xiang; Luo, Lanping; Peng, Feng; Wang, Hongjuan; Yu, Hao

    2018-03-01

    The direct methanol fuel cell is a promising energy conversion device because of the utilization of the state-of-the-art platinum (Pt) anode catalyst. In this work, novel Pt/Ni2P/CNTs catalysts were prepared by the H2 reduction method. It was found that the activity and stability of Pt for methanol oxidation reaction (MOR) could be significantly enhanced while using nickel phosphide (Ni2P) nanoparticles as co-catalyst. X-ray photoelectron spectroscopy revealed that the existence of Ni2P affected the particle size and electronic distribution of Pt obviously. Pt/CNTs catalyst, Pt/Ni2P/CNTs catalysts with different Ni2P amount were synthesized, among which Pt/6%Ni2P/CNTs catalyst exhibited the best MOR activity of 1400 mAmg-1Pt, which was almost 2.5 times of the commercial Pt/C-JM catalyst. Moreover, compared to other Pt-based catalysts, this novel Pt/Ni2P/CNTs catalyst also exhibited higher onset current density and better steady current density. The result of this work may provide positive guidance to the research on high efficiency and stability of Pt-based catalyst for direct methanol fuel cells.

  19. Rare earth metals for automotive exhaust catalysts

    International Nuclear Information System (INIS)

    Shinjoh, Hirohumi

    2006-01-01

    The usage of rare earth metals for automotive exhaust catalysts is demonstrated in this paper. Rare earth metals have been widely used in automotive catalysts. In particular, three-way catalysts require the use of ceria compounds as oxygen storage materials, and lanthana as both a stabilizer of alumina and a promoter. The application for diesel catalysts is also illustrated. Effects of inclusion of rare earth metals in automotive catalysts are discussed

  20. Alkaline Ionic Liquid Modified Pd/C Catalyst as an Efficient Catalyst for Oxidation of 5-Hydroxymethylfurfural

    Directory of Open Access Journals (Sweden)

    Zou Bin

    2018-01-01

    Full Text Available Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL modified Pd/C catalyst (Pd/C-OH−. Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54 mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL could be a substitute and promotion for homogeneous base (NaOH. Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373 K for 24 h.

  1. Platinum Group Metal-free Catalysts for Hydrogen Evolution Reaction in Microbial Electrolysis Cells.

    Science.gov (United States)

    Yuan, Heyang; He, Zhen

    2017-07-01

    Hydrogen gas is a green energy carrier with great environmental benefits. Microbial electrolysis cells (MECs) can convert low-grade organic matter to hydrogen gas with low energy consumption and have gained a growing interest in the past decade. Cathode catalysts for the hydrogen evolution reaction (HER) present a major challenge for the development and future applications of MECs. An ideal cathode catalyst should be catalytically active, simple to synthesize, durable in a complex environment, and cost-effective. A variety of noble-metal free catalysts have been developed and investigated for HER in MECs, including Nickel and its alloys, MoS 2 , carbon-based catalysts and biocatalysts. MECs in turn can serve as a research platform to study the durability of the HER catalysts. This personal account has reviewed, analyzed, and discussed those catalysts with an emphasis on synthesis and modification, system performance and potential for practical applications. It is expected to provide insights into the development of HER catalysts towards MEC applications. © 2017 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hydrogen production by biomass steam gasification in fluidized bed reactor with Co catalyst

    International Nuclear Information System (INIS)

    Kazuhiko Tasaka; Atsushi Tsutsumi; Takeshi Furusawa

    2006-01-01

    The catalytic performances of Co/MgO catalysts were investigated in steam gasification of cellulose and steam reforming of tar derived from cellulose gasification. For steam reforming of cellulose tar in a secondary fixed bed reactor, 12 wt.% Co/MgO catalyst attained more than 80% of tar reduction. The amount of produced H 2 and CO 2 increased with the presence of catalyst, and kept same level during 2 hr at 873 K. It is indicated that steam reforming of cellulose tar proceeds sufficiently over Co/MgO catalyst. For steam gasification of cellulose in a fluidized bed reactor, it was found that tar reduction increases with Co loading amount and 36 wt.% Co/MgO catalyst showed 84% of tar reduction. The amounts of produced gas kept for 2 hr indicating that 36 wt.% Co/MgO catalyst is stable during the reaction. It was concluded that these Co catalysts are promising systems for the steam gasification of cellulose and steam reforming of cellulose tar. (authors)

  3. Carbonaceous deposits on naptha reforming catalysts

    International Nuclear Information System (INIS)

    Redwan, D.S.

    1999-01-01

    Carbonaceous deposits on naphtha reforming catalysts play a decisive role in limiting process performance. The deposits negatively after catalyst activity, selectivity and the production cycle of a semi regenerative reformer. The magnitude of negative effect of those deposits is directly proportional to their amounts and complexity. Investigations on used reforming catalysts samples reveal that the amount and type (complexity of the chemical nature) of carbonaceous deposits are directly proportional to the catalysts life on stream and the severity of operating conditions. In addition, the combustibility behavior of carbonaceous deposits on the catalyst samples taken from different reformers are found to be different. Optimal carbon removal, for in situ catalyst regeneration, requires the specific conditions be developed, based on the results of well designed and properly performed investigations of the amount and type of carbonaceous deposits. (author)

  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. A BGO detector for Positron Emission Profiling in catalysts

    International Nuclear Information System (INIS)

    Mangnus, A.V.G.; Cunningham, R.H.; Santen, R.A. van; Voigt, M.J.A. de

    1995-01-01

    As part of a project to study the reaction kinetics in catalysts, a detector system has been designed and built. The detector will measure in one dimension the activity distribution of positron emitters in catalyst reactors under operational conditions as a function of time. The detector consists of two arrays of ten BGO crystals each and has the flexibility to measure with high sensitivity the activity profile in various reactor sizes; the position resolution that can be reached is 3 mm. (orig.)

  6. Supramolecular water oxidation with rubda-based catalysts

    KAUST Repository

    Richmond, Craig J.; Matheu, Roc; Poater, Albert; Falivene, Laura; Benet-Buchholz, Jordi; Sala, Xavier; Cavallo, Luigi; Llobet, Antoni A.

    2014-01-01

    Extremely slow and extremely fast new water oxidation catalysts based on the Rubda (bda = 2,2′-bipyri-dine-6,6′-dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycless"1, respectively. Detailed analyses

  7. Increasing the lifetime of fuel cell catalysts

    NARCIS (Netherlands)

    Latsuzbaia, R.

    2015-01-01

    In this thesis, I discuss a novel idea of fuel cell catalyst regeneration to increase lifetime of the PEM fuel cell electrode/catalyst operation and, therefore, reduce the catalyst costs. As many of the catalyst degradation mechanisms are difficult to avoid, the regeneration is alternative option to

  8. Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

    KAUST Repository

    Wilhelm, Michael E.; Anthofer, Michael H.; Reich, Robert M.; D'Elia, Valerio; Basset, Jean-Marie; Herrmann, Wolfgang A.; Cokoja, Mirza; Kü hn, Fritz

    2014-01-01

    The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

  9. Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

    KAUST Repository

    Wilhelm, Michael E.

    2014-02-19

    The application of niobium(v) chloride and several imidazolium bromides as catalyst systems for the cycloaddition of propylene oxide (PO) with carbon dioxide to propylene carbonate (PC) is reported. A set of 31 different imidazolium bromides has been synthesized with varying substituents at all five imidazolium ring atoms, of which 17 have not been reported before. The impact of different substitution patterns (steric and electronic changes and solubility in PO) at the imidazolium ring on the catalytic activity was investigated. The optimisation of the catalyst structure allows for the valorisation of carbon dioxide under mild reaction conditions with high reaction rates in very good yield and selectivity for PC. This journal is © the Partner Organisations 2014.

  10. Raising distillate selectivity and catalyst life time in Fischer-Tropsch synthesis by using a novel dual-bed reactor

    International Nuclear Information System (INIS)

    Tavasoli, A.; Sadaghiani, K.; Khodadadi, A. A.; Mortazavi, Y.

    2007-01-01

    In a novel dual bed reactor Fischer-Tropsch synthesis was studied by using two diff rent cobalt catalysts. An alkali-promoted cobalt catalyst was used in the first bed of a fixed-bed reactor followed by a Raiment promoted cobalt catalyst in the second bed. The activity, product selectivity and accelerated deactivation of the system were assessed and compared with a conventional single bed reactor system. The methane selectivity in the dual-bed reactor was about 18.9% less compared to that of the single-bed reactor. The C 5+ selectivity for the dual-bed reactor was 10.9% higher than that of the single-bed reactor. Accelerated deactivation of the catalysts in the dual-bed reactor was 42% lower than that of the single-bed reactor. It was revealed that the amount of catalysts activity recovery after regeneration at 400 d eg C in the dual-bed system is higher than that of the single-bed system

  11. Oxidation of mercury across selective catalytic reduction catalysts in coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Constance L. Senior [Reaction Engineering International, Salt Lake City, UT (United States)

    2006-01-15

    A kinetic model for predicting the amount of mercury (Hg) oxidation across selective catalytic reduction (SCR) systems in coal-fired power plants was developed and tested. The model incorporated the effects of diffusion within the porous SCR catalyst and the competition between ammonia and Hg for active sites on the catalyst. Laboratory data on Hg oxidation in simulated flue gas and slipstream data on Hg oxidation in flue gas from power plants were modeled. The model provided good fits to the data for eight different catalysts, both plate and monolith, across a temperature range of 280-420{sup o}C, with space velocities varying from 1900 to 5000 hr{sup -1}. Space velocity, temperature, hydrochloric acid content of the flue gas, ratio of ammonia to nitric oxide, and catalyst design all affected Hg oxidation across the SCR catalyst. The model can be used to predict the impact of coal properties, catalyst design, and operating conditions on Hg oxidation across SCRs. 20 refs., 9 figs., 2 tabs.

  12. Hydroprocessing using regenerated spent heavy hydrocarbon catalyst

    International Nuclear Information System (INIS)

    Clark, F.T.; Hensley, A.L. Jr.

    1992-01-01

    This patent describes a process for hydroprocessing a hydrocarbon feedstock. It comprises: contacting the feedstock with hydrogen under hydroprocessing conditions with a hydroprocessing catalyst wherein the hydroprocessing catalyst contains a total contaminant metals build-up of greater than about 4 wt. % nickel plus vanadium, a hydrogenation component selected from the group consisting of Group VIB metals and Group VIII metals and is regenerated spent hydroprocessing catalyst regenerated by a process comprising the steps: partially decoking the spent catalyst in an initial coke-burning step; impregnating the partially decoked catalyst with a Group IIA metal-containing impregnation solution; and decoking the impregnated catalyst in a final coke-burning step wherein the impregnated catalyst is contacted with an oxygen-containing gas at a temperature of about 600 degrees F to about 1400 degrees F

  13. The Stability of Supported Gold Catalysts

    NARCIS (Netherlands)

    Masoud, Nazila

    2018-01-01

    Gold has supreme cultural and financial value and, in form of nanoparticles smaller than 10 nm, is a unique catalyst for different industrially relevant reactions. Intriguing properties of the gold catalysts have spurred demand in the chemical industry for Au catalysts, the application of which

  14. Catalysis Science Initiative: Catalyst Design by Discovery Informatics

    Energy Technology Data Exchange (ETDEWEB)

    Delgass, William Nicholas [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Abu-Omar, Mahdi [Purdue Univ., West Lafayette, IN (United States) Department of Chemistry; Caruthers, James [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Ribeiro, Fabio [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Thomson, Kendall [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Schneider, William [Univ. of Notre Dame, IN (United States)

    2016-07-08

    Catalysts selectively enhance the rates of chemical reactions toward desired products. Such reactions provide great benefit to society in major commercial sectors such as energy production, protecting the environment, and polymer products and thereby contribute heavily to the country’s gross national product. Our premise is that the level of fundamental understanding of catalytic events at the atomic and molecular scale has reached the point that more predictive methods can be developed to shorten the cycle time to new processes. The field of catalysis can be divided into two regimes: heterogeneous and homogeneous. For the heterogeneous catalysis regime, we have used the water-gas shift (WGS) reaction (CO + H2O + CO2 + H2O) over supported metals as a test bed. Detailed analysis and strong coupling of theory with experiment have led to the following conclusions: • The sequence of elementary steps goes through a COOH intermediate • The CO binding energy is a strong function of coverage of CO adsorbed on the surface in many systems • In the case of Au catalysts, the CO adsorption is generally too weak on surface with close atomic packing, but the enhanced binding at corner atoms (which are missing bonding partners) of cubo-octahedral nanoparticles increases the energy to a near optimal value and produces very active catalysts. • Reaction on the metal alone cannot account for the experimental results. The reaction is dual functional with water activation occurring at the metal-support interface. It is clear from our work that the theory component is essential, not only for prediction of new systems, but also for reconciling data and testing hypotheses regarding potential descriptors. Particularly important is the finding that the interface between nano-sized metal particles and the oxides that are used to support them represent a new state of matter in the sense that the interfacial bonding perturbs the chemical state of both metals atoms and the support

  15. Templating Routes to Supported Oxide Catalysts by Design

    Energy Technology Data Exchange (ETDEWEB)

    Notestein, Justin M. [Northwestern Univ., Evanston, IL (United States)

    2016-09-08

    The rational design and understanding of supported oxide catalysts requires at least three advancements, in order of increasing complexity: the ability to quantify the number and nature of active sites in a catalytic material, the ability to place external controls on the number and structure of these active sites, and the ability to assemble these active sites so as to carry out more complex functions in tandem. As part of an individual investigator research program that is integrated with the Northwestern University Institute for Catalysis in Energy Processes (ICEP) as of 2015, significant advances were achieved in these three areas. First, phosphonic acids were utilized in the quantitative assessment of the number of active and geometrically-available sites in MOx-SiO2 catalysts, including nanocrystalline composites, co-condensed materials, and grafted structures, for M=Ti, Zr, Hf, Nb, and Ta. That work built off progress in understanding supported Fe, Cu, and Co oxide catalysts from chelating and/or multinuclear precursors to maximize surface reactivity. Secondly, significant progress was made in the new area of using thin oxide overcoats containing ‘nanocavities’ from organic templates as a method to control the dispersion and thermal stability of subsequently deposited metal nanoparticles or other catalytic domains. Similar methods were used to control surface reactivity in SiO2-Al2O3 acid catalysts and to control reactant selectivity in Al2O3-TiO2 photocatalysts. Finally, knowledge gained from the first two areas has been combined to synthesize a tandem catalyst for hydrotreating reactions and an orthogonal tandem catalyst system where two subsequent reactions in a reaction network are independently controlled by light and heat. Overall, work carried out under this project significantly advanced the knowledge of synthesis-structure-function relationships in supported

  16. 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.

  17. FCC catalyst technologies expand limits of process capability

    International Nuclear Information System (INIS)

    Leiby, S.

    1992-01-01

    This paper reports that over the past 30 or so years, many improvements in fluid catalytic cracking (FCC) operation have been achieved as the result of innovations in catalyst formulation. During the 1990s, new environmental regulations on issues such as reformulated gasoline will place new demands on both the refining industry and catalyst suppliers. An overview of cracking catalyst technology therefore seems in order. Today, high-technology innovations by catalyst manufacturers are rapid, but profit margins are slim. Catalyst formulations are shrouded in secrecy and probably depend almost as much on art as on science. Special formulations for specific cracking applications get the greatest emphasis today. To illustrate this point, OGJ's Worldwide Catalyst Report lists over 200 FCC catalyst designations. Catalysts containing components to enhance gasoline octane now account for about 70% of total U.S. FCC catalyst usage

  18. Development of compact tritium confinement system using gas separation membrane

    International Nuclear Information System (INIS)

    Hayashi, Takumi; Okuno, Kenji

    1994-01-01

    In order to develop more compact and cost-effective tritium confinement system for fusion reactor, a new system using gas separation membranes has been studied at the Tritium Process Laboratory in the Japan Atomic Energy Research Institute. The preliminary result showed that the gas separation membrane system could reduce processing volume of tritium contaminated gas to more than one order of magnitude compared with the conventional system, and that most of tritiated water vapor (humidity) could be directly recovered by water condenser before passing through dryer such as molecular sieves. More detail investigations of gas separation characteristics of membrane were started to design ITER Atmospheric Detritiation System (ADS). Furthermore, a scaled polyimide membrane module (hollow-filament type) loop was just installed to investigate the actual tritium confinement performance under various ITER-ADS conditions. (author)

  19. Catalyst Deactivation and Regeneration in Low Temperature Ethanol Steam Reforming with Rh/CeO2-ZrO2 Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hyun-Seog; Platon, Alex; Wang, Yong; King, David L.

    2006-08-01

    Rh/CeO2-ZrO2 catalysts with various CeO2/ZrO2 ratios have been applied to H2 production from ethanol steam reforming at low temperatures. The catalysts all deactivated with time on stream (TOS) at 350 C. The addition of 0.5% K has a beneficial effect on catalyst stability, while 5% K has a negative effect on catalytic activity. The catalyst could be regenerated considerably even at ambient temperature and could recover its initial activity after regeneration above 200 C with 1% O2. The results are most consistent with catalyst deactivation due to carbonaceous deposition on the catalyst.

  20. 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...

  1. The nature of the process of alkylation of isobutane by butenes in zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Patrilyak, K.I.; Bayburskiy, V.L.; Bortyshevskiy, V.A.; Galich, P.N.; Gutyrya, V.S.; Manza, I.A.

    1983-01-01

    The change in the concentration of butenes is studied in a reaction of alkylation of isobutane by butenes in a zeolite catalyst (Kt) in individual zones of a reactor relative to the length of the process. It is shown that the system is characterized by the presence of a period of development of the catalyst, whose length is a function of the conditions of catalyst activation and is from 15 to 20 minutes to 1 hour. Isomerization of butene-1 into butene-2 is discovered. It is shown that the most obvious isomerization is expressed for a catalyst sample active in nonoptimal conditions. The change in the concentration of the butenes in time in individual zones of the catalyst has a wavy nature.

  2. Catalytic decomposition of trichloroethylene over Pt-/Ni-catalyst under microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Takashima, Hideaki; Karches, Martin [Chemiace Laboratory, 36-13 Hon-cho, Hachioji 192-0066 (Japan); Kanno, Yoshinori [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan)], E-mail: kanno@yamanashi.ac.jp

    2008-01-30

    Microwave (MW)-activated catalytic reactor system was studied and the results were compared with that of a conventional system based on the thermal activation method. Trichloroethylene (TCE) was decomposed under various MW-powers supply. Results showed that there is an optimum film thickness that was loaded on supports in MW heating system. The threshold may be within 1-3 {mu}m. Lower temperature cannot activate the catalyst, while higher temperature results in carbon deposition and catalyst deactivation. This means that the dechlorination reaction needs to fix an optimum film MW-power supply in order to avoid the deposition of carbon on the surface of the active phase. MW-activated system is also worth compensating the conventional system in VOCs decomposition reaction.

  3. System Li2O-MoO3 as a catalyst of oxygen (air) electrode

    International Nuclear Information System (INIS)

    Gavdzik, A.; Gajda, S.; Sofronkov, A.

    2000-01-01

    Potential of electrode on the basis of system Li x Mo 2-x O 6 (x 0.1-0.5) in alkaline solution saturated by oxygen was studied by the method of polarization curves recording. It is ascertained that the value of stationary potential characteristic of the electrode described under the conditions mentioned is determined by reversible reaction between oxygen and water molecules, resulting in formation of hydroxyl and hydrogen peroxide anions. Practicability of using the solid solutions on the basis of molybdenum oxide with additions of lithium oxide as a catalyst of oxygen (air) electrode in electrochemical current sources is demonstrated [ru

  4. The formation and influence of carbon on cobalt-based Fischer-Tropsch synthesis catalysts : an integrated review

    NARCIS (Netherlands)

    Moodley, D.J.; Loosdrecht, van de J.; Saib, A.M.; Niemantsverdriet, J.W.; Davis, B.H.; Occelli, M.L.; Speight, J.G.

    2010-01-01

    Cobalt-based Fischer-Tropsch synthesis (FTS) catalysts are the systems of choice for use in gas-to-liquid (GTL) processes. As with most catalysts, cobalt systems gradually lose their activity with increasing time on stream. There are various mechanisms that have been proposed for the deactivation of

  5. Petroleum residue upgrading with dispersed catalysts. Part 1. Catalysts activity and selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Panariti, N.; Del Bianco, A.; Del Piero, G. [ENITECNOLOGIE S.p.A, Via Maritano 26, 20097 San Donato Mil. (Italy); Marchionna, M. [SNAMPROGETTI S.p.A, Via Maritano 26, 20097 San Donato Mil. (Italy)

    2000-12-04

    The results of a study aimed at the identification of the relevant chemical aspects involved in the process of upgrading heavy feedstocks in the presence of dispersed catalysts are discussed. The catalytic activity of different compounds was compared in terms of products yields and quality. Moreover, a detailed and systematic characterization of the catalysts recovered at the end of the reactions was achieved. The experimental work provided quite a large set of data, allowing to investigate the factors that may affect catalyst activity (precursor solubility, rate of activation, degree of dispersion, presence of promoters, etc.). The results of this study demonstrate that the best performances are obtained by the microcrystalline molybdenite generated in situ by oil-soluble precursors. The nature of the organic ligand does not play a very relevant role in influencing the hydrogenation activity. The presence of phosphorus, however, significantly enhances hydrodemetallation, at least in terms of vanadium removal. Bimetallic precursors show a slight synergistic effect towards the hydrodesulfurization reaction. Microsized powdered catalyst precursors have a much lower catalytic activity compared to the oil-soluble ones.

  6. Intermediate Ethanol Blends Catalyst Durability Program

    Energy Technology Data Exchange (ETDEWEB)

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  7. DEVELOPMENT OF PRECIPITATED IRON FISCHER-TROPSCH CATALYSTS

    International Nuclear Information System (INIS)

    Bukur, Dragomir B.; Lang, X.; Chokkaram, S.; Nowicki, L.; Wei, G.; Ding, Y.; Reddy, B.; Xiao, S.

    1999-01-01

    Despite the current worldwide oil glut, the US will ultimately require large-scale production of liquid (transportation) fuels from coal. Slurry phase Fischer-Tropsch (F-T) technology, with its versatile product slate, may be expected to play a major role in production of transportation fuels via indirect coal liquefaction. Some of the F-T catalysts synthesized and tested at Texas A and M University under DOE Contract No. DE-AC22-89PC89868 were more active than any other known catalysts developed for maximizing production of high molecular weight hydrocarbons (waxes). The objectives of the present contract were to demonstrate repeatability of catalyst performance and reproducibility of preparation procedures of two of these catalysts on a laboratory scale. Improvements in the catalyst performance were attempted through the use of: (a) higher reaction pressure and gas space velocity to maximize the reactor productivity; (b) modifications in catalyst preparation steps; and (c) different pretreatment procedures. Repeatability of catalyst performance and reproducibility of catalyst synthesis procedure have been successfully demonstrated in stirred tank slurry reactor tests. Reactor space-time-yield was increased up to 48% by increasing reaction pressure from 1.48 MPa to 2.17 MPa, while maintaining the gas contact time and synthesis gas conversion at a constant value. Use of calcination temperatures above 300 C, additional CaO promoter, and/or potassium silicate as the source of potassium promoter, instead of potassium bicarbonate, did not result in improved catalyst performance. By using different catalyst activation procedures they were able to increase substantially the catalyst activity, while maintaining low methane and gaseous hydrocarbon selectivities. Catalyst productivity in runs SA-0946 and SA-2186 was 0.71 and 0.86 gHC/g-Fe/h, respectively, and this represents 45-75% improvement in productivity relative to that achieved in Rheinpreussen's demonstration plant

  8. Highly Stable and Active Catalyst for Sabatier Reactions

    Science.gov (United States)

    Hu, Jianli; Brooks, Kriston P.

    2012-01-01

    Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

  9. Experimental investigation of attrition resistance of zeolite catalysts in two particle gas-solid-solid fluidization system

    International Nuclear Information System (INIS)

    Nawaz, Z.; Ziaoping, T.; Shu, Q.; Wei, F.; Naveed, S.

    2010-01-01

    In the study of mechanical degradation of 34 ZSM-5 and SAPO catalysts, using the gas jet attrition - ASTM standard fluidized bed test (D-5757), the effect of particle size and its quantitative analysis in co-fluidization environment was investigated on the air jet index (AJI) basis. In gas-solid-solid fluidized bed reactors (GSS-FBR), two different sized particles were fluidized under isothermal conditions. In case of ZSM-5 and SAPO-34, significant attrition resistance was observed, which was attributed to small pore size and specific structural strength of the mobile framework image (MFI) and chabasite (CHA) structures, respectively. The optimum AJI for SAPO-34 and ZSM-5 (of particle size 0.2 mm) in GSS-fluidization system was observed to be 0.0118 and 0.0062, respectively. In co-fluidization, deviations from Gwyn relationship were observed due to change in impact of collision. Therefore, zeolites are recommended as suitable catalysts or catalytic supports (for doping of expensive metals) and for commercial use in GSS-FBR. (author)

  10. Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

    KAUST Repository

    Al-ShaikhAli, Anaam H.

    2016-11-30

    Liquid organic chemical hydride is a promising candidate for hydrogen storage and transport. Methylcyclohexane (MCH) to toluene (TOL) cycle has been considered as one of the feasible hydrogen carrier systems, but selective dehydrogenation of MCH to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based catalysts. Mono-metallic Ni based catalyst is a well-known dehydrogenation catalyst, but the major drawback with Ni is its hydrogenolysis activity to cleave C-C bonds, which leads to inferior selectivity towards dehydrogenation of MCH to TOL. This study elucidate addition of the second metal to Ni based catalyst to improve the TOL selectivity. Herein, ubiquitous bi-metallic nanoparticles catalysts were investigated including (Ni–M, M: Ag, Zn, Sn or In) based catalysts. Among the catalysts investigated, the high TOL selectivity (> 99%) at low conversions was achieved effectively using the supported NiZn catalyst under flow of excess H2. In this work, a combined study of experimental and computational approaches was conducted to determine the main role of Zn over Ni based catalyst in promoting the TOL selectivity. A kinetic study using mono- and bimetallic Ni based catalysts was conducted to elucidate reaction mechanism and site requirement for MCH dehydrogenation reaction. The impact of different reaction conditions (feed compositions, temperature, space velocity and stability) and catalyst properties were evaluated. This study elucidates a distinctive mechanism of MCH dehydrogenation to TOL reaction over the Ni-based catalysts. Distinctive from Pt catalyst, a nearly positive half order with respect to H2 pressure was obtained for mono- and bi-metallic Ni based catalysts. This kinetic data was consistent with rate determining step as (somewhat paradoxically) hydrogenation

  11. A New Energy-Saving Catalytic System: Carbon Dioxide Activation by a Metal/Carbon Catalyst.

    Science.gov (United States)

    Yun, Danim; Park, Dae Sung; Lee, Kyung Rok; Yun, Yang Sik; Kim, Tae Yong; Park, Hongseok; Lee, Hyunjoo; Yi, Jongheop

    2017-09-22

    The conversion of CO 2 into useful chemicals is an attractive method to reduce greenhouse gas emissions and to produce sustainable chemicals. However, the thermodynamic stability of CO 2 means that a lot of energy is required for its conversion into chemicals. Here, we suggest a new catalytic system with an alternative heating system that allows minimal energy consumption during CO 2 conversion. In this system, electrical energy is transferred as heat energy to the carbon-supported metal catalyst. Fast ramping rates allow high operating temperatures (T app =250 °C) to be reached within 5 min, which leads to an 80-fold decrease of energy consumption in methane reforming using CO 2 (DRM). In addition, the consumed energy normalized by time during the DRM reaction in this current-assisted catalysis is sixfold lower (11.0 kJ min -1 ) than that in conventional heating systems (68.4 kJ min -1 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Ionic Liquids as Solvents for Rhodium and Platinum Catalysts Used in Hydrosilylation Reaction

    Directory of Open Access Journals (Sweden)

    Witold Zielinski

    2016-08-01

    Full Text Available A group of imidazolium and pyridinium based ionic liquids has been synthetized, and their ability to dissolve and activate the catalysts used in hydrosilylation reaction of 1-octane and 1,1,1,3,5,5,5-heptamethyltrisiloxane was investigated. An organometallic catalyst as well as inorganic complexes of platinum and rhodium dissolved in ionic liquids were used, forming liquid solutions not miscible with the substrates or with the products of the reaction. The results show that application of such a simple biphasic catalytic system enables reuse of ionic liquid phase with catalysts in multiple reaction cycles reducing the costs and decreasing the amount of catalyst needed per mole of product.

  13. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

    2008-09-01

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  14. Active carbon catalyst for heavy oil upgrading

    Energy Technology Data Exchange (ETDEWEB)

    Fukuyama, Hidetsugu; Terai, Satoshi [Technology Research Center, Toyo Engineering Corporation, 1818 Azafujimi, Togo, Mobara-shi, Chiba 297-00017 (Japan); Uchida, Masayuki [Business Planning and Exploring Department, Overseas Business Development and Marketing Division, Toyo Engineering Corporation, 2-8-1 Akanehama, Narashino-shi, Chiba 275-0024 (Japan); Cano, Jose L.; Ancheyta, Jorge [Maya Crude Treatment Project, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico D.F. 07730 (Mexico)

    2004-11-24

    The active carbon (AC) catalyst was studied by hydrocracking of Middle Eastern vacuum residue (VR) for heavy oil upgrading. It was observed that the active carbon has the affinity to heavy hydrocarbon compounds and adsorption selectivity to asphaltenes, and exhibits better ability to restrict the coke formation during the hydrocracking reaction of VR. The mesopore of active carbon was thought to play an important role for effective conversion of heavy hydrocarbon compounds into lighter fractions restricting carbon formation. The performance of the AC catalyst was examined by continuous hydrocracking by CSTR for the removal of such impurities as sulfur and heavy metals (nickel and vanadium), which are mostly concentrated in the asphaltenes. The AC catalyst was confirmed to be very effective for the removal of heavy metals from Middle Eastern VR, Maya/Istmo VR and Maya VR. The extruded AC catalysts were produced by industrial manufacturing method. The application test of the extruded AC catalyst for ebullating-bed reactor as one of the commercially applicable reactors was carried out at the ebullating-bed pilot plant for 500h. The ebullition of the extruded AC catalyst was successfully traced and confirmed by existing {gamma}-ray density meter. The extruded AC catalyst showed stable performance with less sediment formation at an equivalent conversion by conventional alumina catalyst at commercial ebullating-bed unit. The degradation of the AC catalyst at the aging test was observed to be less than that of the conventional alumina catalyst. Thus, the AC catalyst was confirmed to be effective and suitable for upgrading of heavy oil, especially such heavy oils as Maya, which contains much heavy metals.

  15. Reactivation of a tin oxide-containing catalyst

    Science.gov (United States)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, Kenneth G. (Inventor); Hess, Robert V. (Inventor); Schryer, David R. (Inventor); Sidney, Barry D. (Inventor); Wood, George M. (Inventor); Paulin, Patricia A. (Inventor)

    1989-01-01

    A method for the reactivation of a tin oxide-containing catalyst of a CO.sub.2 laser is provided. First, the catalyst is pretreated by a standard procedure. When the catalyst experiences diminished activity during usage, the heated zone surrounding the catalyst is raised to a temperature which is the operating temperature of the laser and 400.degree. C. for approximately one hour. The catalyst is exposed to the same laser gas mixture during this period. The temperature of the heated zone is then lowered to the operating temperature of the CO.sub.2 laser.

  16. Modified Fe{sub 3}O{sub 4}- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

    Energy Technology Data Exchange (ETDEWEB)

    Valizadeh, S., E-mail: valizadehsolmaz@yahoo.com; Rasoulifard, M.H., E-mail: m_h_rasoulifard@znu.ac.ir; Dorraji, M.S. Seyed, E-mail: dorraji@znu.ac.ir

    2014-11-15

    Graphical abstract: - Highlights: • Photocatalytic degradation of dye by Ag modified HAP under visible light. • Study of Fenton like degradation of dye by transition metal ions modified HAP. • Comparison of catalytic systems according to Langmuir-Hinshelwood kinetic expression. - Abstract: The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag{sub 3}PO{sub 4} formation. Apparent reaction rate constant (K{sub app}) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H{sub 2}O{sub 2}, Co-M-HAP(II)/H{sub 2}O{sub 2} and M-HAP (I)/UV systems, respectively.

  17. Palladium(II/Cationic 2,2’-Bipyridyl System as a Highly Efficient and Reusable Catalyst for the Mizoroki-Heck Reaction in Water

    Directory of Open Access Journals (Sweden)

    Fu-Yu Tsai

    2010-01-01

    Full Text Available A water-soluble and air-stable Pd(NH32Cl2/cationic 2,2’-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu3N as a base. The reaction was conducted at 140 °C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated aryl iodides with butyl and ethyl acrylates, providing the corresponding products in good to excellent yields with very high turnover numbers. In the case of styrene, Mizoroki-Heck coupling products were obtained in good to high yields by using a greater catalyst loading (1 mol % and TBAB as a phase-transfer agent. After extraction, the residual aqueous solution could be reused several times with only a slight decrease in its activity, making the Mizoroki-Heck reaction “greener”.

  18. Removal of VOCs by hybrid electron beam reactor with catalyst bed

    International Nuclear Information System (INIS)

    Kim, Jinkyu; Han, Bumsoo; Kim, Yuri; Lee, J.H.; Park, C.R.; Kim, J.C.; Kim, J.C.; Kim, K.J.

    2004-01-01

    Electron beam decomposition of volatile organic compounds (VOCs) was studied in order to obtain information for developing effective treatment method of off-gases from industries. We have examined the combination of electron beam and catalyst honeycomb which is either 1% platinum based or ceramic honeycomb- based aluminum oxide, using a hybrid reactor in order to improve removal efficiency and CO 2 formation; and to suppress undesirable by-product formation e.g. O 3 , aerosol, H x C y. , and tar. The experiments were conducted using a pilot-scale treatment system (maximum capacity; 1800 N m 3 /h) that fitted the field size to scale up from the traditional laboratory scale system for VOC removal with electron beam irradiation. Toluene was selected as a typical VOC that was irradiated to investigate product formation, effect of ceramic and catalyst, and factors effecting overall efficiency of degradation. Styrene was selected as the most odorous compound among the VOCs of interest. It was found that VOCs could be destroyed more effectively using a hybrid system with catalyst bed than with electron beam irradiation only

  19. Acetic Acid Formation by Selective Aerobic Oxidation of Aqueous Ethanol over Heterogeneous Ruthenium Catalysts

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Hanning, Christopher William

    2012-01-01

    Heterogeneous catalyst systems comprising ruthenium hydroxide supported on different carrier materials, titania, alumina, ceria, and spinel (MgAl2O4), were applied in selective aerobic oxidation ethanol to form acetic acid, an important bulk chemical and food ingredient. The catalysts were...

  20. 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...... along with our recent in situ TEM studies on the sintering of Ni/MgAl2O4 catalysts. These results suggest that the rapid loss of catalyst activity in the earliest stages of catalyst sintering could result from Ostwald ripening rather than through particle migration and coalescence. The smallest...

  1. Catalyst for hydrocarbon conversion

    International Nuclear Information System (INIS)

    Duhaut, P.; Miquel, J.

    1975-01-01

    A description is given for a catalyst and process for hydrocarbon conversions, e.g., reforming. The catalyst contains an alumina carrier, platinum, iridium, at least one metal selected from uranium, vanadium, and gallium, and optionally halogen in the form of metal halide of one of the aforesaid components. (U.S.)

  2. 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.

  3. 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....

  4. Iron-Mediated Homogeneous ICAR ATRP of Methyl Methacrylate under ppm Level Organometallic Catalyst Iron(III Acetylacetonate

    Directory of Open Access Journals (Sweden)

    Jian Wu

    2016-01-01

    Full Text Available Atom Transfer Radical Polymerization (ATRP is an important polymerization process in polymer synthesis. However, a typical ATRP system has some drawbacks. For example, it needs a large amount of transition metal catalyst, and it is difficult or expensive to remove the metal catalyst residue in products. In order to reduce the amount of catalyst and considering good biocompatibility and low toxicity of the iron catalyst, in this work, we developed a homogeneous polymerization system of initiators for continuous activator regeneration ATRP (ICAR ATRP with just a ppm level of iron catalyst. Herein, we used oil-soluble iron (III acetylacetonate (Fe(acac3 as the organometallic catalyst, 1,1′-azobis (cyclohexanecarbonitrile (ACHN with longer half-life period as the thermal initiator, ethyl 2-bromophenylacetate (EBPA as the initiator, triphenylphosphine (PPh3 as the ligand, toluene as the solvent and methyl methacrylate (MMA as the model monomer. The factors related with the polymerization system, such as concentration of Fe(acac3 and ACHN and polymerization kinetics, were investigated in detail at 90 °C. It was found that a polymer with an acceptable molecular weight distribution (Mw/Mn = 1.43 at 45.9% of monomer conversion could be obtained even with 1 ppm of Fe(acac3, making it needless to remove the residual metal in the resultant polymers, which makes such an ICAR ATRP process much more industrially attractive. The “living” features of this polymerization system were further confirmed by chain-extension experiment.

  5. Nuclear Fusion Fuel Cycle Research Perspectives

    International Nuclear Information System (INIS)

    Chung, Hongsuk; Koo, Daeseo; Park, Jongcheol; Kim, Yeanjin; Yun, Sei-Hun

    2015-01-01

    As a part of the International Thermonuclear Experimental Reactor (ITER) Project, we at the Korea Atomic Energy Research Institute (KAERI) and our National Fusion Research Institute (NFRI) colleagues are investigating nuclear fusion fuel cycle hardware including a nuclear fusion fuel Storage and Delivery System (SDS). To have a better knowledge of the nuclear fusion fuel cycle, we present our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). To have better knowledge of the nuclear fusion fuel cycle, we presented our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). Our efforts to enhance the tritium confinement will be continued for the development of cleaner nuclear fusion power plants

  6. Kinetic modelling of slurry polymerization of ethylene with a polymer supported Ziegler-Natta catalyst (hydrogen)

    Energy Technology Data Exchange (ETDEWEB)

    Shariati, A.

    1996-12-31

    The kinetics of polymerization of ethylene catalyzed by a polymer supported Ziegler-Natta catalyst were investigated in a semi-batch reactor system. The influences of six polymerization variables were investigated using a central composite design. The variables were monomer partial pressure, catalyst loading, co-catalyst loading, catalyst particle size and hydrogen to monomer ratio. The influence of temperature on rate and polymer properties were investigated. Empirical models were fitted to the experimental data to quantify the effects of the polymerization variables on the rate characteristics and polymer properties. The rate of polymerization exhibited a first order dependency with respect to monomer partial pressure, but a nonlinear relationship with respect to catalyst loading. In the absence of hydrogen, the polymerization rate showed a non-decaying profile at the centre point conditions for the other variables. Catalyst loading and catalyst particle size had a negligible effect on weight-and-number-average molecular weights, while increasing co-catalysts loading lowered the molecular weights, as did increased temperature and hydrogen concentration. refs., figs.

  7. Molybdenum-containing acidic catalysts to convert cellulosic biomass to glycolic acid

    KAUST Repository

    Han, Yu

    2014-09-30

    Embodiments of the present invention include methods and compositions related to catabolic conversion of cellulosic biomass to glycolic acid using molybdenum-containing acidic catalysts. The invention includes the use of heteropoly and isopoly acids and salts as the molybdenum-containing multi-functional catalysts for biomass conversion. In embodiments of the invention, the reactions employ successive hydrolysis, retro-aldol fragmentation, and selective oxidation in a noble metal-free system.

  8. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts

    Directory of Open Access Journals (Sweden)

    R. Prasad

    2011-05-01

    Full Text Available CuO-CeO2 systems have been proposed as a promising catalyst for low temperature diesel-soot oxidation. CuO-CeO2 catalysts prepared by various methods were examined for air oxidation of the soot in a semi batch tubular flow reactor. The air oxidation of soot was carried out under tight contact with soot/catalyst ratio of 1/10. Air flow rate was 150 ml/min, soot-catalyst mixture was 110 mg, heating rate was 5 0C/min. Prepared catalysts were calcined at 500 0C and their stability was examined by further heating to 800 0C for 4 hours. It was found that the selectivity of all the catalysts was nearly 100% to CO2 production. It was observed that the activity and stability of the catalysts greatly influenced by the preparation methods. The strong interaction between CuO and CeO2 is closely related to the preparation route that plays a crucial role in the soot oxidation over the CuO-CeO2 catalysts. The ranking order of the preparation methods of the catalysts in the soot oxidation performance is as follows: sol-gel > urea nitrate combustion > Urea gelation method > thermal decomposition > co-precipitation. Copyright © 2011 BCREC UNDIP. All rights reserved.(Received: 27th June 2010, Revised: 7th August 2010; Accepted: 13rd October 2010[How to Cite: R. Prasad, V.R. Bella. (2011. Comparison of Preparation Methods of Copper Based PGMFree Diesel-Soot Oxidation Catalysts. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 15-21. doi:10.9767/bcrec.6.1.822.15-21][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.822.15-21 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/822 | View in 

  9. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION; SEMIANNUAL

    International Nuclear Information System (INIS)

    Michael T. Klein

    2000-01-01

    There are several aspects of the Direct Coal Liquefaction process which are not fully understood and which if better understood might lead to improved yields and conversions. Among these questions are the roles of the catalyst and the solvent. While the solvent is known to act by transfer of hydrogen atoms to the free radicals formed by thermal breakdown of the coal in an uncatalyzed system, in the presence of a solid catalyst as is now currently practiced, the yields and conversions are higher than in an uncatalyzed system. The role of the catalyst in this case is not completely understood. DOE has funded many projects to produce ultrafine and more active catalysts in the expectation that better contact between catalyst and coal might result. This approach has met with limited success probably because mass transfer between two solids in a fluid medium i.e. the catalyst and the coal, is very poor. It is to develop an understanding of the role of the catalyst and solvent in Direct Liquefaction that this project was initiated. Specifically it was of interest to know whether direct contact between the coal and the catalyst was important. By separating the solid catalyst in a stainless steel basket permeable to the solvent but not the coal in the liquefaction reactor, it was shown that the catalyst still maintains a catalytic effect on the liquefaction process. There is apparently transfer of hydrogen atoms from the catalyst through the basket wall to the coal via the solvent. Strong hydrogen donor solvents appear to be more effective in this respect than weak hydrogen donors. It therefore appears that intimate contact between catalyst and coal is not a requirement, and that the role of the catalyst may be to restore the hydrogen donor strength to the solvent as the reaction proceeds. A range of solvents of varying hydrogen donor strength was investigated. Because of the extensive use of thermogravimetric analysis in this laboratory in was noted that the peak

  10. Syngas Conversion to Gasoline-Range Hydrocarbons over Pd/ZnO/Al2O3 and ZSM-5 Composite Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A.; Lizarazo Adarme, Jair A.; Lebarbier, Vanessa MC; Gray, Michel J.; White, James F.; King, David L.; Palo, Daniel R.

    2014-07-01

    A composite Pd/ZnO/Al2O3-HZSM-5 (Si/Al=40) catalytic system was evaluated for the synthesis of gasoline-range hydrocarbons directly from synthesis gas. Bifunctional catalyst comprising PdZn metal and acid sites present the required catalytically active sites necessary for the methanol synthesis, methanol dehydration, and methanol-to-gasoline reactions. This system provides a unique catalytic pathway for the production of liquid hydrocarbons directly from syngas. However, selectivity control is difficult and poses many challenges. The composite catalytic system was evaluated under various process conditions. Investigated were the effects of temperature (310-375oC), pressure (300-1000 psig), time-on-stream (50 hrs), and gas-hour space velocity (740-2970 hr-1), using a H2/CO molar syngas ratio of 2.0. By operating at the lower end of the temperature range investigated, liquid hydrocarbon formation was favored, as was decreased amounts of undesirable light hydrocarbons. However, lower operating temperatures also facilitated undesirable CO2 formation via the water-gas shift reaction. Higher operating pressures slightly favored liquid synthesis. Operating at relatively low pressures (e.g. 300 psig) was made possible, whereas for methanol synthesis alone higher pressure are usually required to achieve similar conversion levels (e.g. 1000 psig). Thermodynamic constraints on methanol synthesis are eased by pushing the equilibrium through hydrocarbon formation. Catalytic performance was also evaluated by altering Pd and Zn composition of the Pd/ZnO/Al2O3 catalyst. Of the catalysts and conditions tested, selectivity toward liquid hydrocarbon was highest when using a 5% Pd metal loading and Pd/Zn molar ratio of 0.25 and mixed with HZMS-5, operating at 310oC and 300 psig, CO conversion was 43 % and selectivity (carbon weight basis) to hydrocarbons was 49 wt. %. Of the hydrocarbon fraction, 44wt. % was in the C5-C12 liquid product range and consisted primarily of aromatic

  11. Extraction Of Cobalt From Spent CMB Catalyst Using Supercritical CO2

    Directory of Open Access Journals (Sweden)

    Joo S.-H.

    2015-06-01

    Full Text Available The metal extraction from spent CMB catalyst using supercritical CO2(scCO2 was investigated with single organic system, binary organic system and ternary organic system to extract metal ions. Leaching solution of spent CMB catalyst containing 389 mg L−1 Co2+, 187 mg L−1 Mn2+, 133 mg L−1 Na+, 14.97 mg L−1 Ca2+ and 13.2 mg L−1 Mg2+. The method consists of scCO2/ligands complexation process and metal extraction process at 60°C and 200bar. The result showed the Co and Mn was selectively extracted from Mg, Ca and Na in the ternary system of mixture of Cyanex272, DEA and Alamine304-I.

  12. Supported Catalysts Useful in Ring-Closing Metathesis, Cross Metathesis, and Ring-Opening Metathesis Polymerization

    Directory of Open Access Journals (Sweden)

    Jakkrit Suriboot

    2016-04-01

    Full Text Available Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. This review highlights some of the history of efforts to address these problems, first discussing the problem in the context of reactions like ring-closing metathesis and cross metathesis catalysis used in the synthesis of low molecular weight compounds. It then discusses in more detail progress in dealing with these issues in ring opening metathesis polymerization chemistry. Such approaches depend on a biphasic solid/liquid or liquid separation and can use either always biphasic or sometimes biphasic systems and approaches to this problem using insoluble inorganic supports, insoluble crosslinked polymeric organic supports, soluble polymeric supports, ionic liquids and fluorous phases are discussed.

  13. In Situ Catalytic Groundwater Treatment Using Palladium Catalysts and Horizontal Flow Treatment Wells

    Science.gov (United States)

    2008-01-01

    may enter the soil , and subsequently the groundwater, along any portion of this unlined channel. The area south of the buildings has not been...the 1960s in the northwestern corner of Site 19, and an estimated 250,000 gallons of JP-4 jet fuel were released. Soil was excavated and...16,000 Pd catalyst treatment system $61,000 Pd catalyst with eggshell coating (20 kg @ $245 per lb) $11,000 Skid-mounted reactor system and

  14. exchanged Mg-Al hydrotalcite catalyst

    Indian Academy of Sciences (India)

    ) catalysts, ... The catalyst can be easily separated by simple filtration ... surface area by the single-point N2 adsorption method ... concentration of carbonate anions (by treating the cat- .... hydrotalcite phase along with copper hydroxide and.

  15. Two Catalysts for Selective Oxidation of Contaminant Gases

    Science.gov (United States)

    Wright, John D.

    2011-01-01

    Two catalysts for the selective oxidation of trace amounts of contaminant gases in air have been developed for use aboard the International Space Station. These catalysts might also be useful for reducing concentrations of fumes in terrestrial industrial facilities especially facilities that use halocarbons as solvents, refrigerant liquids, and foaming agents, as well as facilities that generate or utilize ammonia. The first catalyst is of the supported-precious-metal type. This catalyst is highly active for the oxidation of halocarbons, hydrocarbons, and oxygenates at low concentrations in air. This catalyst is more active for the oxidation of hydrocarbons and halocarbons than are competing catalysts developed in recent years. This catalyst completely converts these airborne contaminant gases to carbon dioxide, water, and mineral acids that can be easily removed from the air, and does not make any chlorine gas in the process. The catalyst is thermally stable and is not poisoned by chlorine or fluorine atoms produced on its surface during the destruction of a halocarbon. In addition, the catalyst can selectively oxidize ammonia to nitrogen at a temperature between 200 and 260 C, without making nitrogen oxides, which are toxic. The temperature of 260 C is higher than the operational temperature of any other precious-metal catalyst that can selectively oxidize ammonia. The purpose of the platinum in this catalyst is to oxidize hydrocarbons and to ensure that the oxidation of halocarbons goes to completion. However, the platinum exhibits little or no activity for initiating the destruction of halocarbons. Instead, the attack on the halocarbons is initiated by the support. The support also provides a high surface area for exposure of the platinum. Moreover, the support resists deactivation or destruction by halogens released during the destruction of halocarbons. The second catalyst is of the supported- metal-oxide type. This catalyst can selectively oxidize ammonia to

  16. Polyfunctional catalyst for processiing benzene fractions

    Energy Technology Data Exchange (ETDEWEB)

    G. Byakov; B.D. Zubitskii; B.G. Tryasunov; I.Ya. Petrov [Kuznetsk Basin State Technical University, Kemerovo (Russian Federation)

    2009-05-15

    A by-product of the coke industry is a raw benzene fraction benzene- 1 which may serve as for catalytic processes. The paper reports a study on the influence of the composition and temperatures on the activity and selectivity of NiO-V{sub 2}O{sub 6}-MoO{sub 3}/{gamma}-Al{sub 2}O{sub 3} catalysts and the corresponding binary and tertiary subsystems are studied by a pulse method in model reactions; the hydrodealkylating of toluene and the hydrodesulfurizing of thioprhene. The optimal catalyst composition is established. The new catalyst is compared with industrial catalysts.

  17. Calcium and lanthanum solid base catalysts for transesterification

    Science.gov (United States)

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

    2015-07-28

    In one aspect, a heterogeneous catalyst comprises calcium hydroxide and lanthanum hydroxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In another aspect, a heterogeneous catalyst comprises a calcium compound and a lanthanum compound, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g, and a total basicity of about 13.6 mmol/g. In further another aspect, a heterogeneous catalyst comprises calcium oxide and lanthanum oxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In still another aspect, a process for preparing a catalyst comprises introducing a base precipitant, a neutral precipitant, and an acid precipitant to a solution comprising a first metal ion and a second metal ion to form a precipitate. The process further comprises calcining the precipitate to provide the catalyst.

  18. Effect of catalyst preparation on the yield of carbon nanotube growth

    International Nuclear Information System (INIS)

    Escobar, Mariano; Rubiolo, Gerardo; Candal, Roberto; Goyanes, Silvia

    2009-01-01

    Multi-wall carbon nanotubes (MWCNTs) were synthesized by catalytic chemical vapor deposition (CVD) on catalytic iron nanoparticles dispersed in a silica matrix, prepared by sol gel method. In this contribution, variation of gelation condition on catalyst structure and its influence on the yield of carbon nanotubes growth was studied. The precursor utilized were tetraethyl-orthosilicate and iron nitrate. The sols were dried at two different temperatures in air (25 or 80 deg. C) and then treated at 450 deg. C for 10 h. The xerogels were introduced into the chamber and reduced in a hydrogen/nitrogen (10%v/v) atmosphere at 600 deg. C. MWCNTs were formed by deposition of carbon atoms from decomposition of acetylene at 700 deg. C. The system gelled at RT shows a yield of 100% respect to initial catalyst mass whereas the yield of that gelled at 80 deg. C was lower than 10%. Different crystalline phases are observed for both catalysts in each step of the process. Moreover, TPR analysis shows that iron oxide can be efficiently reduced to metallic iron only in the system gelled at room temperature. Carbon nanotubes display a diameter of about 25-40 nm and several micron lengths. The growth mechanism of MWCNTs is base growth mode for both catalysts.

  19. Effect of catalyst preparation on the yield of carbon nanotube growth

    Energy Technology Data Exchange (ETDEWEB)

    Escobar, Mariano, E-mail: mescobar@df.uba.a [Dep. Quimica Inorganica, Analitica y Quimica Fisica, FCEyN, UBA, Ciudad Universitaria (1428), Bs As (Argentina); LP and MC, Dep. Fisica, FCEyN, UBA (Argentina); Rubiolo, Gerardo [Unidad de Actividad Materiales, CNEA, Av Gral Paz 1499, San Martin (1650), Bs As (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Candal, Roberto [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Instituto de Fisico-quimica de Materiales, Ambiente y Energia (INQUIMAE), CONICET - UBA (Argentina); Goyanes, Silvia [LP and MC, Dep. Fisica, FCEyN, UBA (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

    2009-10-01

    Multi-wall carbon nanotubes (MWCNTs) were synthesized by catalytic chemical vapor deposition (CVD) on catalytic iron nanoparticles dispersed in a silica matrix, prepared by sol gel method. In this contribution, variation of gelation condition on catalyst structure and its influence on the yield of carbon nanotubes growth was studied. The precursor utilized were tetraethyl-orthosilicate and iron nitrate. The sols were dried at two different temperatures in air (25 or 80 deg. C) and then treated at 450 deg. C for 10 h. The xerogels were introduced into the chamber and reduced in a hydrogen/nitrogen (10%v/v) atmosphere at 600 deg. C. MWCNTs were formed by deposition of carbon atoms from decomposition of acetylene at 700 deg. C. The system gelled at RT shows a yield of 100% respect to initial catalyst mass whereas the yield of that gelled at 80 deg. C was lower than 10%. Different crystalline phases are observed for both catalysts in each step of the process. Moreover, TPR analysis shows that iron oxide can be efficiently reduced to metallic iron only in the system gelled at room temperature. Carbon nanotubes display a diameter of about 25-40 nm and several micron lengths. The growth mechanism of MWCNTs is base growth mode for both catalysts.

  20. Advancing Fenton and photo-Fenton water treatment through the catalyst design.

    Science.gov (United States)

    Vorontsov, Alexander V

    2018-04-20

    The review is devoted to modern Fenton, photo-Fenton, as well as Fenton-like and photo-Fenton-like reactions with participation of iron species in liquid phase and as heterogeneous catalysts. Mechanisms of these reactions were considered that include hydroxyl radical and oxoferryl species as the reactive intermediates. The barriers in the way of application of these reactions to wastewater treatment were discussed. The following fundamental problems need further research efforts: inclusion of more mechanism steps and quantum calculations of all rate constants lacking in the literature, checking the outer sphere electron transfer contribution, determination of the causes for the key changes in the homogeneous Fenton reaction mechanism with a change in the reagents concentration. The key advances for Fenton reactions implementation for the water treatment are related to tremendous hydrodynamical effects on the catalytic activity, design of ligands for high rate and completeness of mineralization in short time, and design of highly active heterogeneous catalysts. While both homogeneous and heterogeneous Fenton and photo-Fenton systems are open for further improvements, heterogeneous photo-Fenton systems are most promising for practical applications because of the inherent higher catalyst stability. Modern methods of quantum chemistry are expected to play a continuously increasing role in development of such catalysts. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Novel anode catalyst for direct methanol fuel cells.

    Science.gov (United States)

    Basri, S; Kamarudin, S K; Daud, W R W; Yaakob, Z; Kadhum, A A H

    2014-01-01

    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.

  2. Carbons and carbon supported catalysts in hydroprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, Edward

    2009-07-01

    This book is a comprehensive summary of recent research in the field and covers all areas of carbons and carbon materials. The potential application of carbon supports, particularly those of carbon black (CB) and activated carbon (AC) in hydroprocessing catalysis are covered. Novel carbon materials such as carbon fibers and carbon nano tubes (CNT) are also covered, including the more recent developments in the use of fullerenes in hydroprocessing applications. Although the primary focus of this book is on carbons and carbon supported catalysts, it also identifies the difference in the effect of carbon supports compared with the oxidic supports, particularly that of the Al{sub 2}O{sub 3}. The difference in catalyst activity and stability was estimated using both model compounds and real feeds under variable conditions. The conditions applied during the preparation of carbon supported catalysts are also comprehensively covered and include various methods of pretreatment of carbon supports to enhance catalyst performance. The model compounds results consistently show higher hydrodesulfurization and hydrodeoxygenation activities of carbon supported catalysts than that of the Al{sub 2}O{sub 3} supported catalysts. Also, the deactivation of the former catalysts by coke deposition was much less evident. Chapter 6.3.1.3 is on carbon-supported catalysts: coal-derived liquids.

  3. TiO2-anatase modified by carbon as the photo catalyst under visible light

    International Nuclear Information System (INIS)

    Morawski, A.W.; Janus, M.; Tryba, B.; Kalucki, K.; Tryba, B.; Inagaki, M.

    2006-01-01

    The photo-catalytic oxidation of phenol in water under a visible light over anatase-type titanium dioxide (Tytanpol A11, Poland), modified by carbon deposited via n-hexane carbonization, was investigated. The catalysts, which had small (0-0.2 mass%) and high (0.69-0.85 mass%) contents of carbon showed a little lower catalytic photo-activity than pristine TiO 2 . However, the catalyst with high content of carbon (0.85 mass%) gave almost 14-times lower turbidity in the phenol solution after the photo-catalyst sedimentation. These two factors depend on the carbon content and have an influence on the 'practical efficiency' of the catalysts. The 'practical efficiency' of the catalyst under visible light, calculated from these two factors, was therefore 14-times higher for the catalyst containing 0.85 mass% carbon (whereas for UV radiation, it was found to be lower - 0.2 mass% -; this is the result of a previous work). The surface modification of the catalyst with 0.85% carbon seemed to be stable under visible light. The deposition of carbon on TiO 2 by carbonization of n-hexane was supposed to lead to obtain the catalyst, which could be easily used in a water-treatment system under visible light. (authors)

  4. 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.

  5. Catalysts for oxidation of mercury in flue gas

    Science.gov (United States)

    Granite, Evan J [Wexford, PA; Pennline, Henry W [Bethel Park, PA

    2010-08-17

    Two new classes of catalysts for the removal of heavy metal contaminants, especially mercury (Hg) from effluent gases. Both of these classes of catalysts are excellent absorbers of HCl and Cl.sub.2 present in effluent gases. This adsorption of oxidizing agents aids in the oxidation of heavy metal contaminants. The catalysts remove mercury by oxidizing the Hg into mercury (II) moieties. For one class of catalysts, the active component is selected from the group consisting of iridium (Ir) and iridum-platinum (Ir/Pt) alloys. The Ir and Ir/Pt alloy catalysts are especially corrosion resistant. For the other class of catalyst, the active component is partially combusted coal or "Thief" carbon impregnated with Cl.sub.2. Untreated Thief carbon catalyst can be self-activating in the presence of effluent gas streams. The Thief carbon catalyst is disposable by means of capture from the effluent gas stream in a particulate collection device (PCD).

  6. 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...

  7. Palladium catalysts deposited on silica materials: Comparison of catalysts based on mesoporous and amorphous supports in Heck reaction

    Czech Academy of Sciences Publication Activity Database

    Demel, J.; Čejka, Jiří; Štěpnička, P.

    2010-01-01

    Roč. 329, 1-2 (2010), s. 13-20 ISSN 1381-1169 R&D Projects: GA ČR GA104/09/0561 Institutional research plan: CEZ:AV0Z40400503 Keywords : heterogeneous catalysts * immobolized catalysts * supported catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.872, year: 2010

  8. Structure and catalytic activity of regenerated spent hydrotreating catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.S.; Massoth, F.E.; Furimsky, E. (Utah University, Salt Lake City, UT (USA). Dept. of Fuels Engineering)

    1992-11-01

    Two spent catalysts, obtained from different hydrodemetallation operations, were regenerated by two different treatments, viz. 2% (V/V) O[sub 2]/N[sub 2] and air. One spent catalyst (B), contained 3 wt% V and 15 wt% C, while the other (H) contained 10 wt% V, 14 wt% C and 8 wt% Fe. After regeneration in the O[sub 2]/N[sub 2] stream, catalyst B showed essentially complete recovery of its original surface area, whereas catalyst H showed only 70% recovery. Both catalysts showed substantial losses in surface area by the air treatment. Catalytic activity tests on the regenerated catalysts for hydrodesulfurization of thiophene and for hydrogenation of 1-hexene showed low recovery of activities, even for the regenerated catalyst in which the surface area had been completely recovered. X-ray diffraction analyses of the spent-regenerated catalysts revealed substantial changes in catalyst structure. Surface area and catalytic activity results were qualitatively explained by these catalyst structural changes. 17 refs., 1 fig., 3 tabs.

  9. Synthesis of subnanometer-diameter vertically aligned single-walled carbon nanotubes with copper-anchored cobalt catalysts

    Science.gov (United States)

    Cui, Kehang; Kumamoto, Akihito; Xiang, Rong; An, Hua; Wang, Benjamin; Inoue, Taiki; Chiashi, Shohei; Ikuhara, Yuichi; Maruyama, Shigeo

    2016-01-01

    We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high-quality SWNTs are expected to pave the way to replace silicon for next-generation optoelectronic and photovoltaic devices.We synthesize vertically aligned single-walled carbon nanotubes (VA-SWNTs) with subnanometer diameters on quartz (and SiO2/Si) substrates by alcohol CVD using Cu-anchored Co catalysts. The uniform VA-SWNTs with a nanotube diameter of 1 nm are synthesized at a CVD temperature of 800 °C and have a thickness of several tens of μm. The diameter of SWNTs was reduced to 0.75 nm at 650 °C with the G/D ratio maintained above 24. Scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS-STEM) and high angle annular dark field (HAADF-STEM) imaging of the Co/Cu bimetallic catalyst system showed that Co catalysts were captured and anchored by adjacent Cu nanoparticles, and thus were prevented from coalescing into a larger size, which contributed to the small diameter of SWNTs. The correlation between the catalyst size and the SWNT diameter was experimentally clarified. The subnanometer-diameter and high

  10. Development of industrial hydrogenating catalyst on rhenium base

    International Nuclear Information System (INIS)

    Chistyakova, G.A.; Bat', I.I.; Rebrova, V.V.

    1975-01-01

    Processes for forming rhenium catalysts on carbon carrier and their catalytic properties in nitrobenzene (NB) reduction were studied. Application of an ammonia preparation to the carbon surface produced impregnated carbon saturated at room temperature with a water solution of the ammonia preparation, taken in a volume equal to the volumetric capacity of the carbon. With one impregnation, 2% rhenium was taken up. Catalysts containing more than 5% rhenium were obtained by impregnating the carbon with heating and use of more concentrated solutions. Catalysts made in this way and dried at 100 0 C had the composition Re 2 OH/carbon/. The most active catalysts were those reduced at 200-250 0 C; higher temperatures, up to 300-500 0 C, decreased the activity. Study of the catalytic properties of the rhenium catalysts in a liquid phase reduction of NB showed that the specific activity of rhenium depends only slightly on the content of the active component in the catalyst and is close to the specific activity of palladium and considerably exceeds that of nickel. Study of the effect of the NB concentration and hydrogen pressure on the activity and stability of the 5% rhenium catalyst indicated that with NB concentrations from 50 to 10% the process takes place at an essentially constant rate; the order of the reaction was close to zero with an apparent activation energy of about 7000 cal/mole. At pressures of 15-200 atm the yield with the 5% catalyst was proportional to the hydrogen pressure. A big advantage of the rhenium catalysts in the reduction of NB is their high selectivity. With a higher activity than palladium and nickel catalysts, 5% rhenium catalyst produces a high operating capacity in a wide range of contact charges, which has considerable significance for industrial use in contact apparatus of the column type. Comparison of the costs of rhenium catalysts and granular carbon carrier with those of nickel, platinum, and palladium showed that 5% rhenium catalyst can

  11. Reactivation of a Tin-Oxide-Containing Catalyst

    Science.gov (United States)

    Hess, Robert; Sidney, Barry; Schryer, David; Miller, Irvin; Miller, George; Upchurch, Bill; Davis, Patricia; Brown, Kenneth

    2010-01-01

    The electrons in electric-discharge CO2 lasers cause dissociation of some CO2 into O2 and CO, and attach themselves to electronegative molecules such as O2, forming negative O2 ions, as well as larger negative ion clusters by collisions with CO or other molecules. The decrease in CO2 concentration due to dissociation into CO and O2 will reduce the average repetitively pulsed or continuous wave laser power, even if no disruptive negative ion instabilities occur. Accordingly, it is the primary object of this invention to extend the lifetime of a catalyst used to combine the CO and O2 products formed in a laser discharge. A promising low-temperature catalyst for combining CO and O2 is platinum on tin oxide (Pt/SnO2). First, the catalyst is pretreated by a standard procedure. The pretreatment is considered complete when no measurable quantity of CO2 is given off by the catalyst. After this standard pretreatment, the catalyst is ready for its low-temperature use in the sealed, high-energy, pulsed CO2 laser. However, after about 3,000 minutes of operation, the activity of the catalyst begins to slowly diminish. When the catalyst experiences diminished activity during exposure to the circulating gas stream inside or external to the laser, the heated zone surrounding the catalyst is raised to a temperature between 100 and 400 C. A temperature of 225 C was experimentally found to provide an adequate temperature for reactivation. During this period, the catalyst is still exposed to the circulating gas inside or external to the laser. This constant heating and exposing the catalyst to the laser gas mixture is maintained for an hour. After heating and exposing for an appropriate amount of time, the heated zone around the catalyst is allowed to return to the nominal operating temperature of the CO2 laser. This temperature normally resides in the range of 23 to 100 C. Catalyst activity can be measured as the percentage conversion of CO to CO2. In the specific embodiment

  12. Platinum-Bismuth Bimetallic Catalysts: Synthesis, Characterization and Applications

    OpenAIRE

    Saucedo, Jose A, Jr; Xiao, Yang; Varma, Arvind

    2015-01-01

    Bimetallic catalysts have been explored and shown to exhibit unique characteristics which are not present in monometallic catalysts. Platinum is well known as an effective catalyst for oxidation and reduction reactions, and it can be made more effective when bismuth is introduced as a promotor. Thus, the effectiveness of the Pt-Bi catalyst was demonstrated in prior work. What is not clear, however, is the mechanism behind the catalyst function; why addition of bismuth to platinum decreases de...

  13. Direct dimethyl-ether (DME) synthesis by spatial patterned catalyst arrangement. A modeling and simulation study

    Energy Technology Data Exchange (ETDEWEB)

    McBride, K.; Turek, T.; Guettel, R. [Clausthal Univ. of Technology (Germany). Inst. of Chemical Process Engineering

    2011-07-01

    The effect of spatially patterned catalyst beds was investigated for direct DME synthesis from synthesis gas as an example. A layered arrangement of methanol synthesis and dehydration catalyst was chosen and studied by numerical simulation under typical operating conditions for single-step DME synthesis. It was revealed that catalyst layers significantly influence the DME productivity. With an increasing number of layers from 2 to 40, an increase in DME productivity was observed approaching the performance of a physical catalyst mixture for an infinite number of layers. The results prove that a physical mixture of methanol synthesis and dehydration catalyst achieves the highest DME productivity under operating conditions chosen in this study. This can be explained by the higher average methanol concentration for the layered catalyst arrangement and thus stronger equilibrium constraints for the methanol synthesis reaction. Essentially, the layered catalyst arrangement is comparable to a cascade model of the two-step process, which is less efficient in terms of DME yield than the single-step process. However, since a significant effect was found, the layered catalyst arrangement could be beneficial for other reaction systems. (orig.)

  14. Performance of (CoPC)n catalyst in active lithium-thionyl chloride cells

    Science.gov (United States)

    Shah, Pinakin M.

    1990-01-01

    An experimental study was conducted with anode limited D size cells to characterize the performance of an active lithium-thionyl chloride (Li/SOCl2) system using the polymeric cobalt phthalocyanine, (CoPC)n, catalyst in carbon cathodes. The author describes the results of this experiment with respect to initial voltage delays, operating voltages, and capacities. The effectiveness of the preconditioning methods evolved to alleviate passivation effects on storage are also discussed. The results clearly demonstrated the superior high rate capability of cells with the catalyst. The catalyst did not adversely impact the performance of cells after active storage for up to 6 months, while retaining its beneficial influences.

  15. Correction: A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-12-22

    Correction for 'A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide' by Chee Koon Ng et al., Chem. Commun., 2016, 52, 11842-11845.

  16. Study of (La, Ce)(Pd, Mn, Fe, Co) O3-Perovskite catalysts characterization with nanoparticles produced by compressor and vacuum until 20/000 km and comparison with imported catalyst of Iran Khodro

    International Nuclear Information System (INIS)

    Khanfekr, A.; Arzani, K.; Nemati, A.; Hossaini, M.

    2009-01-01

    (La,Ce)(Pd,Mn,Fe,Co)O 3 - Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure by compressor and vacuum method. The catalyst was applied on Rd car with XU7 motors model and the amount of emission was monitored with vehicle emission test systems in Sapco Company after 10000 and 20/000 Km. The results indicate low emission in catalyst with vacuum method and were compared with the imported catalyst with noble metals such as Palladium, Platinum and Rhodium by Iran Khodro Company b ased on the Euro III standards . The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results indicated in the home made sample, the amount of carbon monoxide, nitrogen oxides and hydrocarbons were lower than imported catalyst with Iran Khodro company with nobel metals. The illustration shows Nano Particles size on coat. The microstructure evaluation showed that the improved properties can he related to the existence of nano particles on coating.

  17. Polymer-bound rhodium hydroformylation catalysts

    NARCIS (Netherlands)

    Jongsma, Tjeerd

    1992-01-01

    Homogeneous catalysts are superior in activity, selectivity as well as specificity, but heterogeneous catalyst are often preferred in industrial processes, because of their good recoverability and their applicability in continuous flow reactors. It would be of great environmental, commercial and

  18. Reductive dechlorination of tetrachlorobisphenol A by Pd/Fe bimetallic catalysts

    International Nuclear Information System (INIS)

    Huang, Qiang; Liu, Wen; Peng, Ping’an; Huang, Weilin

    2013-01-01

    Highlights: • TCBPA can be rapidly and completely dechlorinated by Pd/Fe bimetallic catalysts. • The observed rate constants are functions of dosages, initial concentration, Pd coverage and solution pH. • Pd dosage is the major factor in the observed rates of the reaction. • This is the first report investigating the dechlorination of TCBPA by Pd/Fe catalysts. -- Abstract: The Pd/Fe bimetallic catalysts of micron sizes were synthesized and the rates of tetrachlorobisphenol A (TCBPA) degradation were measured under various conditions using a batch reactor system. The results showed that TCBPA was rapidly dechlorinated to tri-, di- and mono-chlorobisphenol A and to bisphenol A (BPA). The observed rate constants (k obs ) were found to increase as functions of the Pd coverage on the Fe particles and the dosages of the catalysts within the reactors. The k obs value decreased as the initial TCBPA concentration increased, suggesting that the TCBPA dechlorination may follow a surface-site limiting Langmuir–Hinshelwood rate model. The weakly acidic solution, especially at or near pH 6.0, also favored the dechlorination of TCBPA. At pH 6.0, Pd coverage of 0.044 wt% and catalyst dosage of 5 g L −1 , TCBPA with an initial concentration of 20 μM was completely transformed within 60 min, and BPA was detected as the major product through the reaction time. Meanwhile, the k obs values measured at constant solution pH correlated linearly with the mass of particle-bound Pd introduced to the reactors, regardless of Pd/Fe catalyst dosage or Pd surface coverage. This study suggested that Pd/Fe catalysts could be potentially employed to rapidly degrade TCBPA in the contaminated environment

  19. Catalyst design for carbon nanotube growth using atomistic modeling

    International Nuclear Information System (INIS)

    Pint, Cary L; Bozzolo, Guillermo; Hauge, Robert

    2008-01-01

    The formation and stability of bimetallic catalyst particles, in the framework of carbon nanotube growth, is studied using the Bozzolo-Ferrante-Smith (BFS) method for alloys. Monte Carlo-Metropolis simulations with the BFS method are utilized in order to predict and study equilibrium configurations for nanoscale catalyst particles which are directly relevant to the catalyst state prior to growth of carbon nanotubes. At the forefront of possible catalyst combinations is the popular Fe-Mo bimetallic catalyst, which we have recently studied experimentally. We explain our experimental results, which indicate that the growth observed is dependent on the order of co-catalyst deposition, in the straightforward interpretation of BFS strain and chemical energy contributions toward the formation of Fe-Mo catalyst prior to growth. We find that the competition between the formation of metastable inner Mo cores and clusters of surface-segregated Mo atoms in Fe-Mo catalyst particles influences catalyst formation, and we investigate the role of Mo concentration and catalyst particle size in this process. Finally, we apply the same modeling approach to other prominent bimetallic catalysts and suggest that this technique can be a powerful tool to understand and manipulate catalyst design for highly efficient carbon nanotube growth

  20. TECHNOLOGY DEVELOPMENT FOR IRON FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Davis, B.H.

    1998-07-22

    The goal of the proposed work described in this Final Report was the development of iron-based Fischer-Tropsch catalysts that combined high activity, selectivity and life with physical robustness for slurry phase reactors that will produce either low-alpha or high-alpha products. The work described here has optimized the catalyst composition and pretreatment operation for a low-alpha catalyst. In parallel, work has been conducted to design a high-alpha iron catalyst that is suitable for slurry phase synthesis. Studies have been conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors have been studied at the laboratory scale. Catalyst performance has been determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  1. Catalytic Oxidation of Phenol over Zeolite Based Cu/Y-5 Catalyst: Part 1: Catalyst Preparation and Characterization

    Directory of Open Access Journals (Sweden)

    K. Maduna Valkaj

    2015-01-01

    -Mead method of nonlinear regression. On the basis of the obtained results of characterization process and conducted catalytic tests, the following can be observed. Zeolite structure of the prepared catalyst was confirmed through powder X-ray diffraction, scanning electron microscopy and adsorption techniques. Their catalytic performance was monitored in terms of phenol and total organic carbon (TOC conversions, hydrogen peroxide decomposition, by-product distribution and degree of copper leached into the aqueous solution. The obtained experimental results indicate that in the space of 180 minutes, the use of these catalysts allows almost total elimination of phenol and significant removal of total organic carbon content with the use of small amounts of catalyst (0.1 g dm–3 and substoichiometric level (71.4 % of oxidant required for complete oxidation of organic pollutant. The main product among aromatics was catechol, followed by hydroquinone and benzoquinone, which exhibited the typical pattern for a series reaction scheme. The distribution of carboxylic acids was as follows: maleic, fumaric, acetic and oxalic acids. These low-molecular carboxylic acids and aromatic compounds were responsible for the TOC that remained after almost complete removal of phenol. Moreover, one of the most interesting options was to use CWPO as a pre-treatment prior to biological treatment, for simple organic acids that are highly biodegradable. During the reactions, destabilization of the catalyst was observed in terms of leaching of copper from zeolite into the reaction mixture, but the previous investigations of similar catalytic systems showed that the activity of the solid catalyst was not due to the homogeneous contribution of the copper leached from the catalyst, but was more likely due to the activity of the heterogeneous catalyst. Further investigations on the mechanism of catalyst destabilization and methods of stabilization are the subject of the following article in the series. The

  2. Pt-based Bi-metallic Monolith Catalysts for Partial Upgrading of Microalgae Oil

    Energy Technology Data Exchange (ETDEWEB)

    Lawal, Adeniyi [Stevens Inst. of Technology, Hoboken, NJ (United States); Manganaro, James [Anasyn LLC, Princeton, NJ (United States); Goodall, Brian [Valicor Renewables LLC, Dexter, MI (United States); Farrauto, Robert [Columbia Univ., New York, NY (United States)

    2015-03-24

    Valicor’s proprietary wet extraction process in conjunction with thermochemical pre-treatment was performed on algal biomass from two different algae strains, Nannochloropsis Salina (N.S.) and Chlorella to produce algae oils. Polar lipids such as phospholipids were hydrolyzed, and metals and metalloids, known catalyst poisons, were separated into the aqueous phase, creating an attractive “pre-refined” oil for hydrodeoxygenation (HDO) upgrading by Stevens. Oil content and oil extraction efficiency of approximately 30 and 90% respectively were achieved. At Stevens, we formulated a Pt-based bi-metallic catalyst which was demonstrated to be effective in the hydro-treating of the algae oils to produce ‘green’ diesel. The bi-metallic catalyst was wash-coated on a monolith, and in conjunction with a high throughput high pressure (pilot plant) reactor system, was used in hydrotreating algae oils from N.S. and Chlorella. Mixtures of these algae oils and refinery light atmospheric gas oil (LAGO) supplied by our petroleum refiner partner, Marathon Petroleum Corporation, were co-processed in the pilot plant reactor system using the Pt-based bi-metallic monolith catalyst. A 26 wt% N.S. algae oil/74 wt % LAGO mixture hydrotreated in the reactor system was subjected to the ASTM D975 Diesel Fuel Specification Test and it met all the important requirements, including a cetane index of 50.5. An elemental oxygen analysis performed by an independent and reputable lab reported an oxygen content of trace to none found. The successful co-processing of a mixture of algae oil and LAGO will enable integration of algae oil as a refinery feedstock which is one of the goals of DOE-BETO. We have presented experimental data that show that our precious metal-based catalysts consume less hydrogen than the conventional hydrotreating catalyst NiMo Precious metal catalysts favor the hydrodecarbonylation/hydrodecarboxylation route of HDO over the dehydration route preferred by base metal

  3. Mass transfer model liquid phase catalytic exchange column simulation applicable to any column composition profile

    Energy Technology Data Exchange (ETDEWEB)

    Busigin, A. [NITEK USA Inc., Ocala, FL (United States)

    2015-03-15

    Liquid Phase Catalytic Exchange (LPCE) is a key technology used in water detritiation systems. Rigorous simulation of LPCE is complicated when a column may have both hydrogen and deuterium present in significant concentrations in different sections of the column. This paper presents a general mass transfer model for a homogenous packed bed LPCE column as a set of differential equations describing composition change, and equilibrium equations to define the mass transfer driving force within the column. The model is used to show the effect of deuterium buildup in the bottom of an LPCE column from non-negligible D atom fraction in the bottom feed gas to the column. These types of calculations are important in the design of CECE (Combined Electrolysis and Catalytic Exchange) water detritiation systems.

  4. 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.

  5. Removal of H2S from Biogas by Iron (Fe3+ Doped MgO on Ceramic Honeycomb Catalyst using Double Packed Columns System

    Directory of Open Access Journals (Sweden)

    Juntima Chungsiriporn

    2010-03-01

    Full Text Available Hydrogen sulfide is a toxic and corrosive in nature, gas should be safely removed from the biogas streams before subjecting into the fuel cell. Fe3+ doped magnesium oxide was synthesized using sol-gel technique and dip coating process of Fe3+ doped MgO on foam ceramic honeycomb. XRD and SEM indicate that Fe3+ in Fe3+ doped MgO on foam ceramic honeycomb catalyst is finely dispersed in the MgO support. Performance of the synthesized Fe3+ doped magnesium oxide on the honeycomb catalyst was examined for hydrogen sulfide (H2S oxidation by double packed column scrubbers. The absorption column was used for H2S scrubbing from biogas by deionized water absorption and catalytic column was used as catalyst bed for degradation of absorbed H2S in scrubbing water. In the catalytic column, counter current flow of the scrubbing water and air through the catalyst pack was performed for H2S oxidation accompany with catalyst regeneration. System capacity for H2S removal from gas stream showed 98% constant along 3 hr testing time at room temperature.

  6. ZnO nanoparticle catalysts for use in biodiesel production and method of making

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-25

    A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system is comprised of a mixture of zinc oxide and a second metal oxide. The zinc oxide includes a mixture of amorphous zinc oxide and zinc oxide nanocrystals, the zinc nanocrystals having a mean grain size between about 20 and 80 nanometers with at least one of the nanocrystals including a mesopore having a diameter of about 5 to 15 nanometers. Preferably, the second metal oxide is a lanthanum oxide, the lanthanum oxide being selected as one from the group of La.sub.2CO.sub.5, LaOOH, and combinations or mixtures thereof.

  7. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst

    Directory of Open Access Journals (Sweden)

    Luqman Buchori

    2017-05-01

    Full Text Available Biodiesel synthesis through transesterification of soybean oil with methanol on hybrid catalytic-plasma reactor over sulphated zinc oxide (SO42-/ZnO active acid catalyst was investigated. This research was aimed to study effects of Weight Hourly Space Velocity (WHSV and the catalyst diameter on performance of the hybrid catalytic-plasma reactor for biodiesel synthesis. The amount (20.2 g of active sulphated zinc oxide solid acid catalysts was loaded into discharge zone of the reactor. The WHSV and the catalyst diameter were varied between 0.89 to 1.55 min-1 and 3, 5, and 7 mm, respectively. The molar ratio of methanol to oil as reactants of 15:1 is fed to the reactor, while operating condition of the reactor was kept at reaction temperature of 65 oC and ambient pressure. The fatty acid methyl ester (FAME component in biodiesel product was identified by Gas Chromatography - Mass Spectrometry (GC-MS. The results showed that the FAME yield decreases with increasing WHSV. It was found that the optimum FAME yield was achieved of 56.91 % at WHSV of 0.89 min-1 and catalyst diameter of 5 mm and reaction time of 1.25 min. It can be concluded that the biodiesel synthesis using the hybrid catalytic-plasma reactor system exhibited promising the FAME yield. Copyright © 2017 BCREC Group. All rights reserved Received: 15th November 2016; Revised: 24th December 2016; Accepted: 16th February 2017 How to Cite: Buchori, L., Istadi, I., Purwanto, P. (2017. Effects of Weight Hourly Space Velocity and Catalyst Diameter on Performance of Hybrid Catalytic-Plasma Reactor for Biodiesel Synthesis over Sulphated Zinc Oxide Acid Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2: 227-234 (doi:10.9767/bcrec.12.2.775.227-234 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.775.227-234

  8. Practical Aerobic Oxidations of Alcohols and Amines with Homogeneous Cu/TEMPO and Related Catalyst Systems

    Science.gov (United States)

    Ryland, Bradford L.; Stahl, Shannon S.

    2014-01-01

    Alcohol and amine oxidations are common reactions in laboratory and industrial synthesis of organic molecules. Aerobic oxidation methods have long been sought for these transformations, but few practical methods exist that offer advantages over traditional oxidation methods. Recently developed homogeneous Cu/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidinyl-N-oxyl) and related catalyst systems appear to fill this void. The reactions exhibit high levels of chemoselectivity and broad functional-group tolerance, and they often operate efficiently at room temperature with ambient air as the oxidant. These advances, together with their historical context and recent applications, are highlighted in this minireview. PMID:25044821

  9. Investigation of heterogeneous solid acid catalyst performance on low grade feedstocks for biodiesel production: A review

    International Nuclear Information System (INIS)

    Mansir, Nasar; Taufiq-Yap, Yun Hin; Rashid, Umer; Lokman, Ibrahim M.

    2017-01-01

    Highlights: • Solid acid catalysts are proficient to esterifying high free fatty acid feedstocks to biodiesel. • Heterogeneous catalysts have the advantage of easy separation and reusability. • Heterogeneous basic catalysts have limitations due to high FFA of low cost feedstocks. • Solid catalysts having acid and base sites reveal better catalyst for biodiesel production. - Abstract: The conventional fossil fuel reserves are continually declining worldwide and therefore posing greater challenges to the future of the energy sources. Biofuel alternatives were found promising to replace the diminishing fossil fuels. However, conversion of edible vegetable oils to biodiesel using homogeneous acids and base catalysts is now considered as indefensible for the future particularly due to food versus fuel competition and other environmental problems related to catalyst system and feedstock. This review has discussed the progression in research and growth related to heterogeneous catalysts used for biodiesel production for low grade feedstocks. The heterogeneous base catalysts have revealed effective way to produce biodiesel, but it has the limitation of being sensitive to high free fatty acid (FFA) or low grade feedstocks. Alternatively, solid acid catalysts are capable of converting the low grade feedstocks to biodiesel in the presence of active acid sites. The paper presents a comprehensive review towards the investigation of solid acid catalyst performance on low grade feedstock, their category, properties, advantages, limitations and possible remedy to their drawbacks for biodiesel production.

  10. Technology development for iron Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, R.J.; Raje, A.; Keogh, R.A. [and others

    1995-12-31

    The objective of this research project is to develop the technology for the production of physically robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry phase synthesis reactor development. The catalysts that are developed shall be suitable for testing in the Advanced Fuels Development Facility at LaPorte, Texas, to produce either low-or high-alpha product distributions. Previous work by the offeror has produced a catalyst formulation that is 1.5 times as active as the {open_quotes}standard-catalyst{close_quotes} developed by German workers for slurry phase synthesis. In parallel, work will be conducted to design a high-alpha iron catalyst this is suitable for slurry phase synthesis. Studies will be conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors will be studied at the laboratory scale. Catalyst performance will be determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  11. Hydrodeoxygenation of O-containing polycyclic model compounds using a novel organometallic catalyst-precursor

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, S.R.; Song, C.S.; Schobert, H.H. [Pennsylvania State University, University Park, PA (United States). Dept. of Materials Science and Engineering

    1996-09-05

    Compounds containing oxygen functional groups, especially phenols, are undesirable components of coal-derived liquids. Removal of these compounds from the products of coal liquefaction is required. A beneficial alternative would be the removal of these compounds, or the prevention of their formation, during the liquefaction reaction itself, rather than as a separate processing step. A novel organometallic catalyst precursor containing Co and Mo has been studied as a potential hydrogenation catalyst for coal liquefaction. To ascertain the hydrodeoxygenation activity of this catalyst under liquefaction conditions, model compounds were investigated. Anthrone, 2,6-di-r-btuyl-4-methyl-phenol, dinaphthyl ether and xanthene were reacted in the presence of the Co-Mo catalyst precursor and a precursor containing only Mo over a range of temperatures, providing a comparison of conversions to deoxygenated products. These conversions give an indication of the hydrodeoxygenating abilities of organometallic catalyst precursors within a coal liquefaction system. For example, at 400{degree}C dinaphthyl ether was converted 100% (4.5% O-containing products) in the presence of the Co-Mo organometallic precursor, compared to 76.5% conversion (7.4% O-products) in the presence of the Mo catalyst.

  12. Increase oil recovery of heavy oil in combustion tube using a new catalyst based nickel ionic solution

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Garnica, M.A.; Hernandez-Perez, J.R.; Cabrera-Reves, M.C.; Schacht-Hernandez, P. [Inst. Mexicano del Petroleo, Mexico City (Mexico); Mamora, D.D. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Texas A and M Univ., College Station, TX (United States)

    2008-10-15

    An ionic liquid-based nickel catalyst was used in conjunction with a combustion tube as an in situ process for heavy oil. The experimental system was comprised of a fluid injection system; a combustion tube; a fluid production system; a gas chromatograph; and a data recording system. Injected nitrogen and air was controlled by a mass flow controller. Nitrogen was used to pressurize the combustion tube and flush the system. Air was injected at a rate of 3 L per minute throughout the combustion run. Liquids leaving the combustion tube passed through a 2-stage separation process. Gases passing through the condenser were kept at low temperatures. Fractions of produced gas were analyzed by the chromatograph. Data loggers were used to obtain data at 30 second intervals. Two combustion experiments were conducted to obtain production times, temperature profiles, and the quality of the oil produced by the catalyst. Combustion tests were conducted with and without the catalyst. An analysis of the experimental data showed that use of the nickel catalyst resulted in increases in oil production as well as higher combustion efficiencies. Use of the catalyst also resulted in a faster combustion front and accelerated oil production. It was concluded that the produced oil contained fewer impurities than oil produced during the control experiment. 23 refs., 3 tabs., 9 figs.

  13. Iridium-catalyst-based autonomous bubble-propelled graphene micromotors with ultralow catalyst loading.

    Science.gov (United States)

    Wang, Hong; Sofer, Zdeněk; Eng, Alex Yong Sheng; Pumera, Martin

    2014-11-10

    A novel concept of an iridium-based bubble-propelled Janus-particle-type graphene micromotor with very high surface area and with very low catalyst loading is described. The low loading of Ir catalyst (0.54 at %) allows for fast motion of graphene microparticles with high surface area of 316.2 m(2)  g(-1). The micromotor was prepared with a simple and scalable method by thermal exfoliation of iridium-doped graphite oxide precursor composite in hydrogen atmosphere. Oxygen bubbles generated from the decomposition of hydrogen peroxide at the iridium catalytic sites provide robust propulsion thrust for the graphene micromotor. The high surface area and low iridium catalyst loading of the bubble-propelled graphene motors offer great possibilities for dramatically enhanced cargo delivery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 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.

  15. 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...

  16. Nanostructured, mesoporous Au/TiO2 model catalysts – structure, stability and catalytic properties

    Directory of Open Access Journals (Sweden)

    Matthias Roos

    2011-09-01

    Full Text Available Aiming at model systems with close-to-realistic transport properties, we have prepared and studied planar Au/TiO2 thin-film model catalysts consisting of a thin mesoporous TiO2 film of 200–400 nm thickness with Au nanoparticles, with a mean particle size of ~2 nm diameter, homogeneously distributed therein. The systems were prepared by spin-coating of a mesoporous TiO2 film from solutions of ethanolic titanium tetraisopropoxide and Pluronic P123 on planar Si(100 substrates, calcination at 350 °C and subsequent Au loading by a deposition–precipitation procedure, followed by a final calcination step for catalyst activation. The structural and chemical properties of these model systems were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, N2 adsorption, inductively coupled plasma ionization spectroscopy (ICP–OES and X-ray photoelectron spectroscopy (XPS. The catalytic properties were evaluated through the oxidation of CO as a test reaction, and reactivities were measured directly above the film with a scanning mass spectrometer. We can demonstrate that the thin-film model catalysts closely resemble dispersed Au/TiO2 supported catalysts in their characteristic structural and catalytic properties, and hence can be considered as suitable for catalytic model studies. The linear increase of the catalytic activity with film thickness indicates that transport limitations inside the Au/TiO2 film catalyst are negligible, i.e., below the detection limit.

  17. CONVERSION OF (±-CITRONELLAL AND ITS DERIVATIVES TO (--MENTHOL USING BIFUNCTIONAL NICKEL ZEOLITE CATALYSTS

    Directory of Open Access Journals (Sweden)

    Indri Badria Adilina

    2015-06-01

    Full Text Available (±-Citronellal and its derivatives were converted to (--menthol by a one-pot reaction system using zeolite based nickel catalysts. The catalysts were prepared by immobilization of nickel on natural zeolite (NZ or synthetic zeolite (ZSM-5 by a simple cation exchange method. Calcination and hydrogen treatment procedures were able to significantly increase the surface area and pore volume of NZ based catalysts whereas negligible changes in the properties were observed for that of ZSM-5. Catalytic reactions were carried out at 70ºC by stirring the mixture in the air for cyclization of (±-citronellal to (±-isopulegol followed by hydrogenation towards the desired (--menthol at 2 Mpa of H2 pressure. The Ni/NZ catalyst was able to convert a (±-citronellal derivative yielding 9% (--menthol (36% selectivity with conversion up to 24%, whereas Ni/ZSM5 catalyst directly converted 65% (±-citronellal to give 4% menthol (6% selectivity. These zeolite based catalysts are therefore potential materials for the conversion of biomass feed stock to value-added chemicals.

  18. Power generation in microbial fuel cells using platinum group metal-free cathode catalyst: Effect of the catalyst loading on performance and costs.

    Science.gov (United States)

    Santoro, Carlo; Kodali, Mounika; Herrera, Sergio; Serov, Alexey; Ieropoulos, Ioannis; Atanassov, Plamen

    2018-02-28

    Platinum group metal-free (PGM-free) catalyst with different loadings was investigated in air breathing electrodes microbial fuel cells (MFCs). Firstly, the electrocatalytic activity towards oxygen reduction reaction (ORR) of the catalyst was investigated by rotating ring disk electrode (RRDE) setup with different catalyst loadings. The results showed that higher loading led to an increased in the half wave potential and the limiting current and to a further decrease in the peroxide production. The electrons transferred also slightly increased with the catalyst loading up to the value of ≈3.75. This variation probably indicates that the catalyst investigated follow a 2x2e - transfer mechanism. The catalyst was integrated within activated carbon pellet-like air-breathing cathode in eight different loadings varying between 0.1 mgcm -2 and 10 mgcm -2 . Performance were enhanced gradually with the increase in catalyst content. Power densities varied between 90 ± 9 μWcm -2 and 262 ± 4 μWcm -2 with catalyst loading of 0.1 mgcm -2 and 10 mgcm -2 respectively. Cost assessments related to the catalyst performance are presented. An increase in catalyst utilization led to an increase in power generated with a substantial increase in the whole costs. Also a decrease in performance due to cathode/catalyst deterioration over time led to a further increase in the costs.

  19. Sustainable solid catalyst alkylation of commercial olefins by regeneration with supercritical isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar; David N. Thompson; Kyle C. Burch

    2005-12-01

    Supercritical isobutane regeneration of a USY zeolite alkylation catalyst was examined in a continuous, automated reaction / regeneration system. Two feeds were studied; a synthetic isobutane / 2-butene blend, and a commercial refinery isoparaffin / olefin blend. The refinery blend was minimally treated, containing a variety of light olefins, and contaminants, including butadiene, oxygenates and sulfur, which are well known to cause severe catalyst deactivation. Synthetic feed experiments showed that high levels of butene conversion was maintained for more than 200 hours time on stream, and that product quality and catalyst maintenance was relatively stable over the course of the experiment using a 3 hour reaction / 3 hour regeneration cycle. Catalyst activity maintenance was lower when the commercial feed was employed. High levels of alkene conversion were maintained for 78 hours and 192 hours using a 3 hour reaction / 3 hour regeneration cycle and a 2 hour reaction / 2 hour regeneration cycle, respectively.

  20. Synthesis and characterization of catalysts for the selective transformation of biomass-derived materials

    Science.gov (United States)

    Ghampson, Isaac Tyrone

    The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silica-supported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, analyzed as a three-phase system containing Cofcc, Cohcp and CoO particles. Catalyst properties were determined at three stages in catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co3O4, (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. From the study, it was observed that larger pore diameters supported higher turnover frequency; smaller pore diameters yielded larger mole fraction of CoO; XRD on post-reduction and post-FTS catalyst samples indicated significant changes in dispersivity after reduction. In the next section, the catalytic behaviors of unsupported, activated carbon-, alumina-, and SBA-15 mesoporous silica-supported molybdenum nitride catalysts were evaluated for the hydrodeoxygenation of guaiacol (2-methoxy phenol) at 300°C and 5 MPa. The nitride catalysts were prepared by thermal decomposition of bulk and supported ammonium heptamolybdate to form MoO 3 followed by nitridation in either flowing ammonia or a nitrogen/hydrogen mixture. The catalytic properties were strongly affected by the nitriding and purging treatment as well as the physical and chemical properties of support. The overall reaction was influenced by the

  1. Activating catalysts with mechanical force

    NARCIS (Netherlands)

    Piermattei, A.; Karthikeyan, S.; Sijbesma, R.P.

    2009-01-01

    Homogeneously catalysed reactions can be ‘switched on’ by activating latent catalysts. Usually, activation is brought about by heat or an external chemical agent. However, activation of homogeneous catalysts with a mechanical trigger has not been demonstrated. Here, we introduce a general method to

  2. Possibilities of tritium removal from waste waters of pressurized water reactors and fuel reprocessing plants

    International Nuclear Information System (INIS)

    Ribnikar, S.V.; Pupezin, J.D.

    1975-01-01

    Starting from parameters known for heavy water production processes, a parallel was made with separation of tritium from water. The quantity in common is the total cascade flow. The most efficient processes appear to be hydrogen sulfide, water exchange, hydrogen- and water distillation. Prospects of application of new processes are discussed briefly. Problems concerning detritiation of pressurized water reactors and large fuel reprocessing plants are analyzed. Detritiation of the former should not present problems. With the latter, economical detritiation can be achieved only after some plant flow patterns are changed. (U.S.)

  3. Role of ultrasonic irradiation on transesterification of palm oil using calcium oxide as a solid base catalyst

    International Nuclear Information System (INIS)

    Poosumas, Jutipong; Ngaosuwan, Kanokwan; Quitain, Armando T.; Assabumrungrat, Suttichai

    2016-01-01

    Highlights: • Transesterification of palm oil using a circulated continuous flow ultrasonic reactor. • Heterogeneous system using CaO as catalyst. • Effects of ultrasonic frequency and power, and catalyst reusability were considered. • A single high frequency and high intensity irradiation is favorable for heterogeneous system. - Abstract: Biodiesel production from transesterification of palm oil using a circulated continuous flow ultrasonic reactor was investigated. Transesterification was carried out at 60 °C, 1 atm and a methanol-to-oil molar ratio of 9:1. The highest reaction rate was achieved at the catalyst loading of 2 wt%, and biodiesel yield constantly increased until transesterification equilibrium (about 80%) was reached. A higher ultrasonic frequency (50 kHz) promoted the heterogeneously catalyzed transesterification of refined palm oil, because the three-phase system (packed solid catalyst, methanol and oil) required more spatial distribution by ultrasonic irradiation. Moreover, the highest ultrasonic power also provided highest transesterification rate and biodiesel yield due to cavitation activity enhancement. Reusability of calcium oxide catalysts was also investigated, and results showed that this can be reused to provide high biodiesel yield for at least three operations with slight decrease in the rate of reaction due to counter balance effect of organic compounds deposition on the catalyst surface. The results from this study can be a basis for scaling up of the process to industrial scale.

  4. National Ignition Facility environmental protection systems

    International Nuclear Information System (INIS)

    Mintz, J.M.; Reitz, T.C.; Tobin, M.T.

    1994-06-01

    The conceptual design of Environmental Protection Systems (EPS) for the National Ignition Facility (NIF) is described. These systems encompass tritium and activated debris handling, chamber, debris shield and general decontamination, neutron and gamma monitoring, and radioactive, hazardous and mixed waste handling. Key performance specifications met by EPS designs include limiting the tritium inventory to 300 Ci and total tritium release from NIF facilities to less than 10 Ci/yr. Total radiation doses attributable to NIF shall remain below 10 mrem/yr for any member of the general public and 500 mrem/yr for NIF staff. ALARA-based design features and operational procedures will, in most cases, result in much lower measured exposures. Waste minimization, improved cycle time and reduced exposures all result from the proposed CO2 robotic arm cleaning and decontamination system, while effective tritium control is achieved through a modern system design based on double containment and the proven detritiation technology

  5. Demonstration of an Emergency Containment System

    International Nuclear Information System (INIS)

    Flanagan, T.M.; Rogers, M.L.; Wilkes, W.R.

    1978-01-01

    A system called an Emergency Containment System (ECS) to be used for tertiary containment of tritium was reported at the 13th Air Cleaning Conference. This system was part of the Tritium Effluent Control Laboratory then under construction at Mound Facility. A series of experiments has recently been conducted to evaluate the performance of an ECS in capturing tritium accidentally released into an operating laboratory. The ECS is an automatically actuated laboratory air detritiation system utilizing a catalytic oxidation reactor and presaturated oxide adsorption/exchange columns. In the event of an accidental release of tritium into the laboratory, the ECS is automatically activated, and quick-acting pneumatic dampers divert the laboratory air supply and exhaust through the ECS until room concentrations are returned to safe operating levels. The results of the experiments have shown that a tertiary containment of tritium is feasible. In the event of a catastrophic accident, the ECS is capable of preventing the release of a large quantity of tritium to the environment

  6. Surface science models of CoMoS hydrodesulfurisation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, A.M.; De Beer, V.H.J.; Van Veen, J.A.R.; Niemantsverdriet, J.W. [Schuit Institute of Catalysis, Eindhoven University of Technology, Eindhoven (Netherlands)

    1997-07-01

    Characterization of supported catalysts with surface spectroscopic techniques is often limited due to restraints imposed by the support material. The use of flat conducting substrates as a model support offers a way to apply these techniques to their full potential. Such surface science models of silica and alumina supported CoMoS catalysts have been made by impregnating thin SiO{sub 2} and Al{sub 2}O{sub 3} films with a solution of nitrilotriacetic acid (NTA) complexes of cobalt and molybdenum. X-ray Photoelectron Spectroscopy (XPS) spectra indicate that the order in which cobalt and molybdenum transfer to the sulfided state is reversed with respect to oxidic Co and Mo systems prepared by conventional methods, implying that NTA complexation retards the sulfidation of cobalt to temperatures where MoS{sub 2} is already formed. Catalytic tests show that the CoMoS model catalysts exhibit activities for thiophene desulfurisation and product distributions similar to those of their high surface area counterparts. 25 refs.

  7. Progress on the mechanistic understanding of SO2 oxidation catalysts

    DEFF Research Database (Denmark)

    Lapina, Olga B.; Bal'zhinimaev, B.S.; Boghosian, Soghomon

    1999-01-01

    Production, Goskhimizdat (in Russian), Moscow, 1954, p. 348]. In recent years these catalysts have also been used to clean flue gases and other SO; containing, industrial off-gases. In spite of the importance and long utilization of these industrial processes, the catalytic active species and the reaction......For almost a century vanadium oxide based catalysts have been the dominant materials in industrial processes for sulfuric acid production. A vast body of information leading to fundamental knowledge on the catalytic process was obtained by Academician [G.K. Boreskov, Catalysis in Sulphuric Acid...... mechanism. A multiinstrumental investigation that combine the efforts of four groups from four different countries has been carried out on the model system as well as on working industrial catalysts. Detailed information has been obtained on the complex and on the redox chemistry of vanadium. Based on this...

  8. The physical chemistry and materials science behind sinter-resistant catalysts.

    Science.gov (United States)

    Dai, Yunqian; Lu, Ping; Cao, Zhenming; Campbell, Charles T; Xia, Younan

    2018-06-18

    Catalyst sintering, a main cause of the loss of catalytic activity and/or selectivity at high reaction temperatures, is a major concern and grand challenge in the general area of heterogeneous catalysis. Although all heterogeneous catalysts are inevitably subjected to sintering during their operation, the immediate and drastic consequences can be mitigated by carefully engineering the catalytic particles and their interactions with the supports. In this tutorial review, we highlight recent progress in understanding the physical chemistry and materials science involved in sintering, including the discussion of advanced techniques, such as in situ microscopy and spectroscopy, for investigating the sintering process and its rate. We also discuss strategies for the design and rational fabrication of sinter-resistant catalysts. Finally, we showcase recent success in improving the thermal stability and thus sinter resistance of supported catalytic systems.

  9. Dearomatization of jet fuel on irradiated platinum-supported catalyst

    International Nuclear Information System (INIS)

    Mucka, V.; Ostrihonova, A.; Kopernicky, I.; Mikula, O.

    1983-01-01

    The effect of ionizing radiation ( 60 Co #betta#-rays) on Pt-supported catalyst used for the dearomatization of jet fuel with distillation in the range 395 to 534 K has been studied. Pre-irradiation of the catalyst with doses in the range 10 2 to 5 x 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 approx. 60 to 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. (author)

  10. Catalyst design for enhanced sustainability through fundamental surface chemistry.

    Science.gov (United States)

    Personick, Michelle L; Montemore, Matthew M; Kaxiras, Efthimios; Madix, Robert J; Biener, Juergen; Friend, Cynthia M

    2016-02-28

    Decreasing energy consumption in the production of platform chemicals is necessary to improve the sustainability of the chemical industry, which is the largest consumer of delivered energy. The majority of industrial chemical transformations rely on catalysts, and therefore designing new materials that catalyse the production of important chemicals via more selective and energy-efficient processes is a promising pathway to reducing energy use by the chemical industry. Efficiently designing new catalysts benefits from an integrated approach involving fundamental experimental studies and theoretical modelling in addition to evaluation of materials under working catalytic conditions. In this review, we outline this approach in the context of a particular catalyst-nanoporous gold (npAu)-which is an unsupported, dilute AgAu alloy catalyst that is highly active for the selective oxidative transformation of alcohols. Fundamental surface science studies on Au single crystals and AgAu thin-film alloys in combination with theoretical modelling were used to identify the principles which define the reactivity of npAu and subsequently enabled prediction of new reactive pathways on this material. Specifically, weak van der Waals interactions are key to the selectivity of Au materials, including npAu. We also briefly describe other systems in which this integrated approach was applied. © 2016 The Author(s).

  11. Soot oxidation over NOx storage catalysts. Activity and deactivation

    International Nuclear Information System (INIS)

    Krishna, K.; Makkee, M.

    2006-01-01

    Soot oxidation activity and deactivation of NO x storage and reduction (NSR) catalysts containing Pt, K, and Ba supported on Al 2 O 3 , are studied under a variety of reaction conditions. K-containing catalysts decrease soot oxidation temperature with O 2 alone and the presence of Pt further enhance the activity due to synergetic effect. The active species responsible for synergism on Pt/K-Al 2 O 3 are unstable and cannot be regenerated. Soot oxidation temperature decreases by about 150 o C with NO+O 2 exhaust feed gas and under lean conditions NSR system acts as catalysed soot filter (CSF). The reactions that are mainly responsible for decreasing soot oxidation temperature are: (1) soot oxidation with NO 2 followed by NO recycles to NO 2 , and (2) soot oxidation with O 2 assisted by NO 2 . Only a part of the stored NO x that is decomposed at high temperatures under lean conditions is found to be useful for soot oxidation. NO x storage capacity of NSR catalysts decreases upon ageing under soot oxidising conditions. This will lead to a decreased soot oxidation activity on stored nitrate decomposition. Pt/K-Al 2 O 3 catalyst is more active, but least stable compared with Pt/Ba-Al 2 O 3 . (author)

  12. Vertically-oriented graphenes supported Mn3O4 as advanced catalysts in post plasma-catalysis for toluene decomposition

    Science.gov (United States)

    Bo, Zheng; Hao, Han; Yang, Shiling; Zhu, Jinhui; Yan, Jianhua; Cen, Kefa

    2018-04-01

    This work reports the catalytic performance of vertically-oriented graphenes (VGs) supported manganese oxide catalysts toward toluene decomposition in post plasma-catalysis (PPC) system. Dense networks of VGs were synthesized on carbon paper (CP) via a microwave plasma-enhanced chemical vapor deposition (PECVD) method. A constant current approach was applied in a conventional three-electrode electrochemical system for the electrodeposition of Mn3O4 catalysts on VGs. The as-obtained catalysts were characterized and investigated for ozone conversion and toluene decomposition in a PPC system. Experimental results show that the Mn3O4 catalyst loading mass on VG-coated CP was significantly higher than that on pristine CP (almost 1.8 times for an electrodeposition current of 10 mA). Moreover, the decoration of VGs led to both enhanced catalytic activity for ozone conversion and increased toluene decomposition, exhibiting a great promise in PPC system for the effective decomposition of volatile organic compounds.

  13. Characterization of catalysts by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Targos, W.M.; Bradley, S.A.

    1989-01-01

    The dedicated scanning transmission electron microscope (STEM) is an integral tool for characterizing catalysts because of its unique ability to image and analyze nanosized volumes. This information is valuable in optimizing catalyst formulations and determining causes for reduced catalyst performance. For many commercial catalysts direct correlations between structural features of metal crystallites and catalytic performance are not attainable. When these instances occur, determination of elemental distribution may be the only information available. In this paper the authors discuss some of the techniques employed and limitations associated with characterizing commercial catalysts

  14. Selective catalyst reduction light-off strategy

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-10-18

    An emissions control system includes a temperature determination module and an emissions control module. The temperature determination module determines a first temperature of a heater element of a diesel particulate filter (DPF) assembly in an exhaust system and determines a second temperature of a catalyst of the DPF assembly. The emissions control module selectively activates the heater element, selectively initiates a predefined combustion process in an engine based upon the first temperature, and selectively starts a reductant injection process based upon the second temperature.

  15. DEVELOPMENT OF ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    International Nuclear Information System (INIS)

    Adeyinka A. Adeyiga

    2001-01-01

    The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+H 2 ) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H 2 /CO ratios. However, a serious problem with use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment, makes the separation of catalyst from the oil/wax product very difficult if not impossible, and results in a steady loss of catalyst from the reactor. Recently, fundamental understanding of physical attrition is being addressed by incorporating suitable binders into the catalyst recipe. This has resulted in the preparation of a spray dried Fe-based catalyst having aps of 70 mm with high attrition resistance. This Fe-based attrition resistant, active and selective catalyst gave 95% CO conversion through 125 hours of testing in a fixed-bed at 270 C, 1.48 MPa, H 2 /CO=0.67 and 2.0 NL/g-cat/h with C 5 + selectivity of >78% and methane selectivity of <5%. However, further development of the catalyst is needed to address the chemical attrition due to phase changes that any Fe-catalyst goes through potentially causing internal stresses within the particle and resulting in weakening, spalling or cracking. The objective of this research is to develop robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry bubble column reactor. Specifically we aim to develop to: (i) improve the performance and preparation procedure of the high activity, high attrition resistant, high alpha iron

  16. 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.

  17. Low platinum catalyst and method of preparation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Di-Jia; Chong, Lina

    2017-11-21

    A low platinum catalyst and method for making same. The catalyst comprises platinum-transition metal bimetallic alloy microcrystallites over a transition metal-nitrogen-carbon composite. A method of making a catalyst comprises preparation of transition metal organic frameworks, infusion of platinum, thermal treatment, and reduction to form the microcrystallites and composite.

  18. 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.

  19. Roles of K2O on the CaO-ZnO Catalyst and Its Influence on Catalyst Basicity for Biodiesel Production

    Science.gov (United States)

    Buchori, Luqman; Istadi, I.; Purwanto; Marpaung, Louis Claudia; Safitri, Rahmatika Luthfiani

    2018-02-01

    This research aimed to study the effect of K2O impregnation on the basicity of the CaO-ZnO catalyst and its effect on biodiesel production. The effect of mole ratio of CaO to ZnO catalyst and %wt K2O were also studied. The mole ratio of CaO to ZnO catalyst was varied at 1:1, 1:1.5, 1:2, 1:3, and 3:1, while the %wt K2O was varied at 1, 3, and 5 %. The catalyst basicity was determined by titration method. The basicity of the catalyst increased after the CaO-ZnO catalyst was impregnated with K2O in all mole ratios of CaO-ZnO catalyst. The addition of K2O as a promoter also increase the basicity. The highest basicity was obtained at the CaO-ZnO mole ratio of 3:1 and 5%wt K2O. The tranesterification process was carried out in a batch reactor at a methanol to oil mole ratio of 15:1, a reaction temperature of 60°C, a reaction time of 4 h, and a catalyst loading of 5%wt oil. The FAME yields obtained were 41.33%. These results proved that K2O plays a role in enhancing the catalyst basicity. In addition, K2O also serves as a binding agent to improve the mechanical properties of the catalyst.

  20. Surface heterogeneity and ionization of Cs promoter in carbon-based ruthenium catalyst for ammonia synthesis

    International Nuclear Information System (INIS)

    Kotarba, Andrzej; Dmytrzyk, Jaromir; Rarog-Pilecka, Wioletta; Kowalczyk, Zbigniew

    2003-01-01

    Second-generation ammonia synthesis cesium-doped ruthenium catalyst supported on turbostratic carbon was investigated by the species resolved thermal alkali desorption method (SR-TAD). Energetic barriers for cesium ions (2.86 eV), ground state (1.96 eV) and electronically excited atoms (5.76 eV) desorbing from the Cs-Ru/C catalyst were determined. In the case of ruthenium-free Cs/C system, cesium desorbs as ground state atoms only, with an energy barrier of 2.87 eV. The work functions determined by the thermionic emission of electrons from Cs/C and Cs-Ru/C were of the same value (2.9 eV). It was concluded that ruthenium induces heterogeneous distribution of cesium on the catalyst surface. The promoter stability is reduced on low work function areas and its surface ionization on high work function areas opens the ionic desorption channel. The Cs desorption from the catalyst is discussed in terms of the literature data for the cesium/graphite system

  1. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D [Swedish Cancer Institute, Seattle, WA (United States)

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  2. Lunar CATALYST

    Data.gov (United States)

    National Aeronautics and Space Administration — Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) is a NASA initiative to encourage the development of U.S. private-sector robotic lunar...

  3. Coupling molecular catalysts with nanostructured surfaces for efficient solar fuel production

    Science.gov (United States)

    Jin, Tong

    Solar fuel generation via carbon dioxide (CO2) reduction is a promising approach to meet the increasing global demand for energy and to minimize the impact of energy consumption on climate change. However, CO2 is thermodynamically stable; its activation often requires the use of appropriate catalysts. In particular, molecular catalysts with well-defined structures and tunability have shown excellent activity in photochemical CO2 reduction. These homogenous catalysts, however, suffer from poor stability under photochemical conditions and difficulty in recycling from the reaction media. Heterogenized molecular catalysts, particularly those prepared by coupling molecular catalysts with solid-state surfaces, have attracted more attention in recent years as potential solutions to address the issues associated with molecular catalysts. In this work, solar CO2 reduction is investigated using systems coupling molecular catalysts with robust nanostructured surfaces. In Chapter 2, heterogenization of macrocyclic cobalt(III) and nickel (II) complexes on mesoporous silica surface was achieved by different methods. Direct ligand derivatization significantly lowered the catalytic activity of Co(III) complex, while grafting the Co(III) complex onto silica surface through Si-O-Co linkage resulted in hybrid catalysts with excellent activity in CO2 reduction in the presence of p-terphenyl as a molecular photosensitizer. An interesting loading effect was observed, in which the optimal activity was achieved at a medium Co(III) surface density. Heterogenization of the Ni(II) complex on silica surface has also been implemented, the poor photocatalytic activity of the hybrid catalyst can be attributed to the intrinsic nature of the homogeneous analogue. This study highlighted the importance of appropriate linking strategies in preparing functional heterogenized molecular catalysts. Coupling molecular complexes with light-harvesting surfaces could avoid the use of expensive molecular

  4. Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

    Science.gov (United States)

    Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

    2011-01-01

    To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

  5. Bi-metallic catalysts, methods of making, and uses thereof

    KAUST Repository

    Basset, Jean-Marie

    2017-01-19

    Provided herein are bi-metallic catalysts, methods of making, and uses thereof. In some embodiments, the bi-metallic catalyst contains two different metal catalysts that can be used in hydrocarbon metathesis reactions, in some embodiments, the methods of making the bi-metallic catalysts can include two steps utilizing a surface organometallic chemistry approach in which the two different metal catalysts are sequentially grafted onto a support.

  6. Bi-metallic catalysts, methods of making, and uses thereof

    KAUST Repository

    Basset, Jean-Marie; Samantaray, Manoja K.; Dey, Raju; Abou-Hamad, Edy; Kavitake, Santosh

    2017-01-01

    Provided herein are bi-metallic catalysts, methods of making, and uses thereof. In some embodiments, the bi-metallic catalyst contains two different metal catalysts that can be used in hydrocarbon metathesis reactions, in some embodiments, the methods of making the bi-metallic catalysts can include two steps utilizing a surface organometallic chemistry approach in which the two different metal catalysts are sequentially grafted onto a support.

  7. Alternative deNO{sub x} catalysts and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Due-Hansen, J.

    2010-06-15

    Two approaches are undertaken in the present work to reduce the emission of NO{sub x}: by means of catalytic removal, and by NO absorption in ionic liquids. The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N{sub 2}. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts in the flue gas when biomass is combusted. By co-firing with large amounts of CO{sub 2}-neutral straw or wood (to meet stringent CO{sub 2} emission legislation), the lifetime of the traditional SCR catalyst is thus significantly reduced due to the presence of deactivating species originating from the fuel. To develop 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 active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V{sub 2}O{sub 5}-SO{sub 4}2-ZrO{sub 2}. This work, together with an introduction to the catalytic removal of NO{sub x}, are described in chapter 3. The remainder of the first part is concerned with the catalytic NO{sub x} removal (chapter 4) and it addresses the upscaling of the best catalyst candidate. The catalyst was mixed with the natural binding clay (sepiolite) to upscale the selected catalyst to the monolithic level, suitable for installation in gas stream with high flows, e.g. a flue gas duct of a power plant. A series of catalyst pellets with increasing levels of sepiolite were

  8. Radio-Frequency-Based NH₃-Selective Catalytic Reduction Catalyst Control: Studies on Temperature Dependency and Humidity Influences.

    Science.gov (United States)

    Dietrich, Markus; Hagen, Gunter; Reitmeier, Willibald; Burger, Katharina; Hien, Markus; Grass, Philippe; Kubinski, David; Visser, Jaco; Moos, Ralf

    2017-07-12

    The upcoming more stringent automotive emission legislations and current developments have promoted new technologies for more precise and reliable catalyst control. For this purpose, radio-frequency-based (RF) catalyst state determination offers the only approach for directly measuring the NH₃ loading on selective catalytic reduction (SCR) catalysts and the state of other catalysts and filter systems. Recently, the ability of this technique to directly control the urea dosing on a current NH₃ storing zeolite catalyst has been demonstrated on an engine dynamometer for the first time and this paper continues that work. Therefore, a well-known serial-type and zeolite-based SCR catalyst (Cu-SSZ-13) was investigated under deliberately chosen high space velocities. At first, the full functionality of the RF system with Cu-SSZ-13 as sample was tested successfully. By direct RF-based NH₃ storage control, the influence of the storage degree on the catalyst performance, i.e., on NO x conversion and NH₃ slip, was investigated in a temperature range between 250 and 400 °C. For each operation point, an ideal and a critical NH₃ storage degree was found and analyzed in the whole temperature range. Based on the data of all experimental runs, temperature dependent calibration functions were developed as a basis for upcoming tests under transient conditions. Additionally, the influence of exhaust humidity was observed with special focus on cold start water and its effects to the RF signals.

  9. Synthesis of Cyclododecatriene from 1,3-Butadiene by Trimerization over Amine-Titanium Complex Catalyst

    International Nuclear Information System (INIS)

    Park, Da Min; Kim, Gye Ryung; Lee, Ju Hyun; Kim, Geon-Joong; Cho, Deuk Hee

    2013-01-01

    The new complex catalysts were synthesized by the reaction of titanium compounds (titanium chloride or titanium butoxide) and diamines in this work, and they showed very high catalytic activities for the cyclododecatriene (CDT) synthesis from 1,3-butadiene through trimerization. CDT synthetic reaction was performed in an autoclave reactor, and the effects of reaction temperature, type of catalyst, catalyst amount added into the system, the mole ratio of Al/Ti and immobilization method were investigated on the yield of product CDT. The titanium complex catalyst combined to diamine with 1:1 ratio showed high selectivity to CDT more than 90%. The ratio of TTT-CDT/TTC-CDT isomers in the product revealed as different values, depending on the type of diamine combined to titanium and Ti/diamine ratios. Those homogeneous complexes could be used as a heterogenized catalyst after anchoring on the supports, and the immobilized titanium catalyst retained the catalytic activities for several times in the recycled reactions without leaching. The carbon support containing titanium has exhibited superior activity to the silica support. Especially, when the titanium complex was anchored on the support which was fabricated by the hydrolysis of tripropylaminosilane itself, the resulting titanium catalyst showed the highest BD conversion and CDT selectivity

  10. Surface science approach to Pt/carbon model catalysts: XPS, STM and microreactor studies

    Science.gov (United States)

    Motin, Abdul Md.; Haunold, Thomas; Bukhtiyarov, Andrey V.; Bera, Abhijit; Rameshan, Christoph; Rupprechter, Günther

    2018-05-01

    Pt nanoparticles supported on carbon are an important technological catalyst. A corresponding model catalyst was prepared by physical vapor deposition (PVD) of Pt on sputtered HOPG (highly oriented pyrolytic graphite). The carbon substrate before and after sputtering as well as the Pt/HOPG system before and after Pt deposition and annealing were examined by XPS and STM. This yielded information on the surface density of defects, which serve as nucleation centres for Pt, and on the size distribution (mean size/height) of the Pt nanoparticles. Two different model catalysts were prepared with mean sizes of 2.0 and 3.6 nm, both turned out to be stable upon UHV-annealing to 300 °C. After transfer into a UHV-compatible flow microreactor and subsequent cleaning in UHV and under mbar pressure, the catalytic activity of the Pt/HOPG model system for ethylene hydrogenation was examined under atmospheric pressure flow conditions. This enabled to determine temperature-dependent conversion rates, turnover frequencies (TOFs) and activation energies. The catalytic results obtained are in line with the characteristics of technological Pt/C, demonstrating the validity of the current surface science based model catalyst approach.

  11. Method of Heating a Foam-Based Catalyst Bed

    Science.gov (United States)

    Fortini, Arthur J.; Williams, Brian E.; McNeal, Shawn R.

    2009-01-01

    A method of heating a foam-based catalyst bed has been developed using silicon carbide as the catalyst support due to its readily accessible, high surface area that is oxidation-resistant and is electrically conductive. The foam support may be resistively heated by passing an electric current through it. This allows the catalyst bed to be heated directly, requiring less power to reach the desired temperature more quickly. Designed for heterogeneous catalysis, the method can be used by the petrochemical, chemical processing, and power-generating industries, as well as automotive catalytic converters. Catalyst beds must be heated to a light-off temperature before they catalyze the desired reactions. This typically is done by heating the assembly that contains the catalyst bed, which results in much of the power being wasted and/or lost to the surrounding environment. The catalyst bed is heated indirectly, thus requiring excessive power. With the electrically heated catalyst bed, virtually all of the power is used to heat the support, and only a small fraction is lost to the surroundings. Although the light-off temperature of most catalysts is only a few hundred degrees Celsius, the electrically heated foam is able to achieve temperatures of 1,200 C. Lower temperatures are achievable by supplying less electrical power to the foam. Furthermore, because of the foam s open-cell structure, the catalyst can be applied either directly to the foam ligaments or in the form of a catalyst- containing washcoat. This innovation would be very useful for heterogeneous catalysis where elevated temperatures are needed to drive the reaction.

  12. Friedel-Crafts Alkylation of o-xylene over V2O5/ZrO2 Catalysts

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-01-01

    Full Text Available The present study has undertaken the Friedel-Crafts benzylation of aromatics over the V2O5/ZrO2 catalysts systems. Catalysts with different V2O5 content (0-15wt %) was prepared by wet impregnation method and characterized by XRD, BET surface area...

  13. Encapsulated heterogeneous base catalysts onto SBA-15 nanoporous material as highly active catalysts in the transesterification of sunflower oil to biodiesel

    Science.gov (United States)

    Albayati, Talib M.; Doyle, Aidan M.

    2015-02-01

    Alkali metals and their hydroxides, Na, NaOH, Li, and LiOH, were encapsulated onto SBA-15 nanoporous material as highly active catalysts for the production of biodiesel fuel from sunflower oil. The incipient wetness impregnation method was adopted for the prepared catalysts. The characterization properties of the catalysts and unmodified SBA-15 were determined using X-ray diffraction, scanning electron microscopy, EDAX, nitrogen adsorption-desorption porosimetry (Brunauer-Emmett-Teller), Fourier-transform infrared spectroscopy, and transmission electron microscopy. Transesterification was conducted in a batch reactor at atmospheric pressure and 65 °C. The catalysts were highly active with yields of fatty acid methyl ester (FAME) in the range 96-99 %. Na/SBA-15 catalyst was reused for seven consecutive cycles under the same reaction conditions; the yield to FAME on the final cycle was 96 %. This study shows that the alkali metals and their hydroxides supported on SBA-15-based catalyst are excellent catalysts for the biodiesel reaction.

  14. Encapsulated heterogeneous base catalysts onto SBA-15 nanoporous material as highly active catalysts in the transesterification of sunflower oil to biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Albayati, Talib M., E-mail: talib-albyati@yahoo.com [University of Technology, Department of Chemical Engineering (Iraq); Doyle, Aidan M., E-mail: a.m.doyle@mmu.ac.uk [Manchester Metropolitan University, Division of Chemistry and Environmental Science (United Kingdom)

    2015-02-15

    Alkali metals and their hydroxides, Na, NaOH, Li, and LiOH, were encapsulated onto SBA-15 nanoporous material as highly active catalysts for the production of biodiesel fuel from sunflower oil. The incipient wetness impregnation method was adopted for the prepared catalysts. The characterization properties of the catalysts and unmodified SBA-15 were determined using X-ray diffraction, scanning electron microscopy, EDAX, nitrogen adsorption–desorption porosimetry (Brunauer–Emmett–Teller), Fourier-transform infrared spectroscopy, and transmission electron microscopy. Transesterification was conducted in a batch reactor at atmospheric pressure and 65 °C. The catalysts were highly active with yields of fatty acid methyl ester (FAME) in the range 96–99 %. Na/SBA-15 catalyst was reused for seven consecutive cycles under the same reaction conditions; the yield to FAME on the final cycle was 96 %. This study shows that the alkali metals and their hydroxides supported on SBA-15-based catalyst are excellent catalysts for the biodiesel reaction.

  15. Encapsulated heterogeneous base catalysts onto SBA-15 nanoporous material as highly active catalysts in the transesterification of sunflower oil to biodiesel

    International Nuclear Information System (INIS)

    Albayati, Talib M.; Doyle, Aidan M.

    2015-01-01

    Alkali metals and their hydroxides, Na, NaOH, Li, and LiOH, were encapsulated onto SBA-15 nanoporous material as highly active catalysts for the production of biodiesel fuel from sunflower oil. The incipient wetness impregnation method was adopted for the prepared catalysts. The characterization properties of the catalysts and unmodified SBA-15 were determined using X-ray diffraction, scanning electron microscopy, EDAX, nitrogen adsorption–desorption porosimetry (Brunauer–Emmett–Teller), Fourier-transform infrared spectroscopy, and transmission electron microscopy. Transesterification was conducted in a batch reactor at atmospheric pressure and 65 °C. The catalysts were highly active with yields of fatty acid methyl ester (FAME) in the range 96–99 %. Na/SBA-15 catalyst was reused for seven consecutive cycles under the same reaction conditions; the yield to FAME on the final cycle was 96 %. This study shows that the alkali metals and their hydroxides supported on SBA-15-based catalyst are excellent catalysts for the biodiesel reaction

  16. Catalyst study for the plasma exhaust purification process

    International Nuclear Information System (INIS)

    Chabot, J.; Sannier, J.

    1990-01-01

    Several catalysts available from commercial sources have been screened to find out specific catalysts which allow complete methane oxidation and ammonia decomposition at temperature as low as possible in order to minimize tritium loss by permeation through processing equipment walls. Afterwards, an extended kinetic investigation has been performed on the best catalysts to achieve the data necessary to unit calculations. For methane oxidation, a palladium on alumina catalyst shows a very satisfactory low-temperature efficiency while a non-precious metal catalyst made of nickel oxide and alumina was found to be the more efficient for ammonia decomposition

  17. Visible-light-driven methane formation from CO2 with a molecular iron catalyst

    Science.gov (United States)

    Rao, Heng; Schmidt, Luciana C.; Bonin, Julien; Robert, Marc

    2017-08-01

    Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.

  18. Attrition resistant Fischer-Tropsch catalyst and support

    Science.gov (United States)

    Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

    2004-05-25

    A catalyst support having improved attrition resistance and a catalyst produced therefrom. The catalyst support is produced by a method comprising the step of treating calcined .gamma.-alumina having no catalytic material added thereto with an acidic aqueous solution having an acidity level effective for increasing the attrition resistance of the calcined .gamma.-alumina.

  19. MASS TRANSFER IN PORE STRUCTURES OF SUPPORTED CATALYSTS

    Directory of Open Access Journals (Sweden)

    F.R.C. Silva

    1997-09-01

    Full Text Available The effects of gas-solid interaction and mass transfer in fixed-bed systems of supported catalysts were analyzed for g -Al2O3 (support and Cu/g -Al2O3 (catalyst systems. Evaluations of the mass transfer coefficients in the macropores and of the diffusivity in the micropores, as formed by the crystallite agglomerates of the metallic phases, were obtained. Dynamic experiments with gaseous tracers permitted the quantification of the parameters based on models for these two pore structures. With a flow in a range of 18 cm3 s-1 to 39.98 cm3 s-1 at 45oC, 65oC and 100oC, mass transfer coefficients km =4.33x10-4 m s-1 to 7.38x10-4 m s-1 for macropore structures and diffusivities Dm =1.29x10-11 m2 s-1 to 5.35x10-11 m2 s-1 for micropore structures were estimated

  20. Iron doped fibrous-structured silica nanospheres as efficient catalyst for catalytic ozonation of sulfamethazine.

    Science.gov (United States)

    Bai, Zhiyong; Wang, Jianlong; Yang, Qi

    2018-04-01

    Sulfonamide antibiotics are ubiquitous pollutants in aquatic environments due to their large production and extensive application. In this paper, the iron doped fibrous-structured silica (KCC-1) nanospheres (Fe-KCC-1) was prepared, characterized, and applied as a catalyst for catalytic ozonation of sulfamethazine (SMT). The effects of ozone dosage, catalyst dosage, and initial concentration of SMT were examined. The experimental results showed that Fe-KCC-1 had large surface area (464.56 m2 g -1 ) and iron particles were well dispersed on the catalyst. The catalyst had high catalytic performance especially for the mineralization of SMT, with mineralization ratio of about 40% in a wide pH range. With addition of Fe-KCC-1, the ozone utilization increased nearly two times than single ozonation. The enhancement of SMT degradation was mainly due to the surface reaction, and the increased mineralization of SMT was due to radical mechanism. Fe-KCC-1 was an efficient catalyst for SMT degradation in catalytic ozonation system.