WorldWideScience

Sample records for catalytic converters

  1. Heated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This article describes how the use of an auxiliary burner to heat the converter promptly can provide substantially decreased emission levels. While, in principle, there may well be solutions to decreasing warm-up phase hydrocarbon emissions, their production-level implementation is hindered by conflicting requirements, insufficiently mature technologies, and significant technical and financial restraints. The US, California, and the European Community are tightening emission standards for the transitional-low-, low-, and ultra-low-emission vehicles throughout the coming decade. The lead figure shows the fundamental possibilities for reducing harmful substances in exhaust emissions. While one can distinguish between measures taken within the engine (internal), and others outside it (external), it currently seems that only a combination of both will provide a suitable overall concept.

  2. Combined catalytic converter and afterburner

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-30

    This patent describes the combined use of a catalytic converter and afterburner. An afterburner chamber and a catalyst matrix are disposed in series within a casing. A combustible premixed charge is ignited in the afterburner chamber before it enters the catalyst matrix. This invention overcomes the problem encountered in previous designs of some of the premixed charge passing unreacted through the device unless a very long afterburner chamber is used. (UK)

  3. Reducing catalytic converter pressure loss

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    This article examines why approximately 30--40% of total exhaust-system pressure loss occurs in the catalytic converter and what can be done to reduce pressure loss. High exhaust-system backpressure is of concern in the design of power trains for passenger cars and trucks because it penalizes fuel economy and limits peak power. Pressure losses occur due to fluid shear and turning during turbulent flow in the converter headers and in entry separation and developing laminar-flow boundary layers within the substrate flow passages. Some of the loss mechanisms are coupled. For example, losses in the inlet header are influenced by the presence of the flow resistance of a downstream substrate. Conversely, the flow maldistribution and pressure loss of the substrate(s) depend on the design of the inlet header.

  4. Estimating the temperature of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-02

    A method is described for estimating the temperature in a catalytic converter used in the exhaust system of an internal combustion engine. Pressure sensors monitor the flow resistance across the catalytic converter to provide an indication of the temperature inside. This feedback system allows heating devices to be switched off and thus avoid overheating, while maintaining the catalytic converter's efficiency by assuring that it does not operate below its light off temperature. (UK)

  5. Estimating the temperature of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-11-02

    A method of estimating the temperature of a catalytic converter used in the exhaust system of an internal combustion engine is described. Heated exhaust gas oxygen (HEGO) sensors are placed upstream and downstream of the catalytic converter. The temperature of the catalytic converter shortly after start-up is measured by monitoring the resistance of the HEGO sensor's heating element. The downstream sensor is used for mixture control and to double check results of the upstream sensor. (UK)

  6. Catalytic converter with thermoelectric generator

    Energy Technology Data Exchange (ETDEWEB)

    Parise, R.J.

    1998-07-01

    The unique design of an electrically heated catalyst (EHC) and the inclusion of an ECO valve in the exhaust of an internal combustion engine will meet the strict new emission requirements, especially at vehicle cold start, adopted by several states in this country as well as in Europe and Japan. The catalytic converter (CC) has been a most useful tool in pollution abatement for the automobile. But the emission requirements are becoming more stringent and, along with other improvements, the CC must be improved to meet these new standards. Coupled with the ECO valve, the EHC can meet these new emission limits. In an internal combustion engine vehicle (ICEV), approximately 80% of the energy consumed leaves the vehicle as waste heat: out the tail pipe, through the radiator, or convected/radiated off the engine. Included with the waste heat out the tail pipe are the products of combustion which must meet strict emission requirements. The design of a new CC is presented here. This is an automobile CC that has the capability of producing electrical power and reducing the quantity of emissions at vehicle cold start, the Thermoelectric Catalytic Power Generator. The CC utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. Thus an electrically heated catalyst (EHC) will be used to augment the abatement of tail pipe emissions. Included with the EHC in the exhaust stream of the automobile is the ECO valve. This valve restricts the flow of pollutants out the tail pipe of the vehicle for a specified amount of time until the EHC comes up to operating temperature. Then the ECO valve opens and allows the full exhaust, now treated by the EHC, to leave the vehicle.

  7. Acoustics of automotive catalytic converter assemblies

    Science.gov (United States)

    Dickey, Nolan S.; Selamet, Ahmet; Parks, Steve J.; Tallio, Kevin V.; Miazgowicz, Keith D.; Radavich, Paul M.

    2003-10-01

    In an automotive exhaust system, the purpose of the catalytic converter is to reduce pollutant emissions. However, catalytic converters also affect the engine and exhaust system breathing characteristics; they increase backpressure, affect exhaust system acoustic characteristics, and contribute to exhaust manifold tuning. Thus, radiated sound models should include catalytic converters since they can affect both the source characteristics and the exhaust system acoustic behavior. A typical catalytic converter assembly employs a ceramic substrate to carry the catalytically active noble metals. The substrate has numerous parallel tubes and is mounted in a housing with swelling mat or wire mesh around its periphery. Seals at the ends of the substrate can be used to help force flow through the substrate and/or protect the mat material. Typically, catalytic converter studies only consider sound propagation in the small capillary tubes of the substrate. Investigations of the acoustic characteristics of entire catalytic converter assemblies (housing, substrate, seals, and mat) do not appear to be available. This work experimentally investigates the acoustic behavior of catalytic converter assemblies and the contributions of the separate components to sound attenuation. Experimental findings are interpreted with respect to available techniques for modeling sound propagation in ceramic substrates.

  8. Vacuum-insulated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Benson, David K. (Golden, CO)

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  9. Catalytic Converters Maintain Air Quality in Mines

    Science.gov (United States)

    2014-01-01

    At Langley Research Center, engineers developed a tin-oxide based washcoat to prevent oxygen buildup in carbon dioxide lasers used to detect wind shears. Airflow Catalyst Systems Inc. of Rochester, New York, licensed the technology and then adapted the washcoat for use as a catalytic converter to treat the exhaust from diesel mining equipment.

  10. Stable solutions for a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, H.; Norbury, J. (Univ. of Oxford (United Kingdom). Mathematical Inst.)

    1994-06-01

    A coupled system of partial differential equations that describes the evolution of solid and gas temperatures and gas concentration inside a catalytic converter is derived and examined. The use of a reaction term, which is a discontinuous function of the solid temperature and gas concentration, implies that two types of nontrivial solutions may occur. These are characterized by the manner in which the reaction switches off: either the solid temperature becomes too low (U-solutions) or the gaseous concentration is exhausted (G-solutions). This reaction term differs from the usual combustion term because the reaction is modeled as two-stage, with the large activation-energy limit then justifying the step-function approach adopted. First, steady solutions for which the gas and solid are in thermal equilibrium are studied, and a constraint relating the system's parameters is derived as a necessary condition for the existence of such solutions. Explicit solutions are presented for a particular class of reaction rates, with a linear stability analysis of one case indicating that G-solutions are stable while U-solutions are not. Steady solutions for which the solid and gas are no longer in thermal equilibrium are then considered. For a particular asymptotic limit (and choice of the reaction term), the construction of asymptotic power series expansions shows that the gas temperature exceeds the solid temperature at all points inside the converter. The analysis indicates that separate treatment of the solid and gaseous temperatures has no effect on the qualitative nature of the steady solutions, that is, their existence, stability, and parameter dependence.

  11. Advanced catalytic converter system for natural gas powered diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Strots, V.O.; Bunimovich, G.A.; Matros, Y.S. [Matros Technologies Inc., Chesterfield, Missouri (United States); Zheng, M.; Mirosh, E.A. [Alternative Fuel Systems Inc., Calgary, Alberta (Canada)

    1998-12-31

    The paper discusses the development of catalytic converter for aftertreatment of exhaust gas from diesel engines powered with natural gas. The converter, operated with periodical reversals of the flow, ensures destruction of CO and hydrocarbons, including methane. Both computer simulation and engine testing results are presented. 8 refs.

  12. Temperature control of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T.T.-H.

    1994-06-08

    In an ic engine having a catalytic convertor, the catalyst heater is controlled in dependence upon an estimate of the temperature of the catalyst so that there is no need for a sensor in the hostile environment of the exhaust. A valve indicative of the catalyst temperature is stored and modified in accordance with a model of the catalyst temperature. The model can be a mathematical mood carried out by a signal processor or an electrical model with the catalyst temperature being represented by the charge stored on a capacitor. (Author)

  13. Catalytic converter for next generation turbine engines

    Energy Technology Data Exchange (ETDEWEB)

    Saruhan, B.; Schulz, U.; Leyens, C. [German Aerospace Center (DLR), Inst. of Materials Research, Cologne (Germany)

    2004-07-01

    EB-PVD thermal barrier coatings (TBCs) are used on advanced turbine blades to increase the engine efficiency and improve the blade performance. partially yttria stabilized zirconia (PYSZ) is the standard material for current TBC applications. Lower thermal stability of the PYSZ-based TBCs, however, seriously affects the performance at demanding service temperatures. For the new generation turbines where higher operating gas temperatures (> 1200 C) are to expect, the performance of turbine blades can be improved by replacing the state-art-of-material PYSZ with superior thermal barrier coatings which belong to different crystal structures such as magnetoplumbite. Magnetoplumbite structure through its interlocking grain morphology and unique crystal structure provides essentially a sintering resistant, low thermal conductive layer, but also imparts a catalytic layer to reduce the environmentally harmful substances produced during propulsion and increase the catalytic performance. The complex structures of these compounds make it difficult to realize by conventional methods and requires careful adjustment of process parameters. The morphology and crystallographic aspects of these coatings as well as the mechanisms controlling the improvement are highlighted. (orig.)

  14. A simplified thermal model for the three way catalytic converter

    OpenAIRE

    Pandey, Varun; JEANNERET, Bruno; GILLET, Sylvain; KEROMNES, Alan; Le Moyne, Luis

    2016-01-01

    A semi empirical model based on thermodynamic behaviour of a three way catalytic converter has been proposed to predict temperature evolution of the converter during the cold start. The model is based on energy and mass balance in the TWC considered as control volume. Parameters of the heat equations are identified separately using a step by step approach. Thermocouples have been inserted along the monolith canals to measure the axial evolution of temperature. Experiments on the engine test b...

  15. Removal of platinum group metals from the used auto catalytic converter

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2009-04-01

    Full Text Available Recycling of platinum group metals from the used auto catalytic converters is profitable from ecological and also economical point of view. This work presents the analysis of the chances of removing the platinum group metals (PGM from the used auto catalytic converters applying pyrometallurgical and hydrometallurgical methods. The characteristics of auto catalytic converter is shown as well the available technologies used for processing the auto catalytic converters are also presented.

  16. Life Cycle Analysis of a Ceramic Three-Way Catalytic Converter

    OpenAIRE

    Belcastro, Elizabeth Lynn

    2012-01-01

    The life cycle analysis compares the environmental impacts of catalytic converters and the effects of not using these devices. To environmentally evaluate the catalytic converter, the emissions during extraction, processing, use of the product are considered. All relevant materials and energy supplies are evaluated for the catalytic converter. The goal of this life cycle is to compare the pollutants of a car with and without a catalytic converter. Pollutants examined are carbon monoxide (...

  17. Removal of platinum group metals from the used auto catalytic converter

    OpenAIRE

    A. Fornalczyk; M. Saternus

    2009-01-01

    Recycling of platinum group metals from the used auto catalytic converters is profitable from ecological and also economical point of view. This work presents the analysis of the chances of removing the platinum group metals (PGM) from the used auto catalytic converters applying pyrometallurgical and hydrometallurgical methods. The characteristics of auto catalytic converter is shown as well the available technologies used for processing the auto catalytic converters are also presented.

  18. Catalytic converter modeling for optimal gasoline-HEV energy management

    OpenAIRE

    Michel, Pierre; Charlet, Alain; Colin, Guillaume; Chamaillard, Yann; Bloch, Gérard; Nouillant, Cédric

    2014-01-01

    International audience A simple multi-0D model of a 3-Way Catalytic Converter (3WCC) is built from physical equations, integrating the temperature dynamics and a pollutant emission conversion map. The validated model involves complexity and performances suitable to be integrated in a high fidelity powertrain model of a gasoline-Hybrid Electric Vehicle (HEV). Next, a pollutant constrained optimal energy management is derived from the Pontryagin Minimum Principle. The approach allows the joi...

  19. Preparation and Use of a Room-Temperature Catalytic Converter

    Science.gov (United States)

    Wong, Gareth; Mark, Bernard; Chen, Xijia; Furch, Toran; Singmaster, K. A.; Wagenknecht, Paul S.

    2001-12-01

    A solid-state catalyst that effectively converts a CO/air mixture to CO2 at room temperature is readily prepared. The catalyst, which is composed of metallic gold on iron(III) oxide, is loaded into a simple flow cell to test its catalytic activity. Mixtures of CO and air are run through the catalyst and subsequently analyzed by gas-phase infrared spectroscopy to determine the effectiveness of the catalyst.

  20. Applications and benefits of catalytic converter thermal management

    Energy Technology Data Exchange (ETDEWEB)

    Burch, S.D.; Keyser, M.A.; Colucci, C.P.; Potter, T.F.; Benson, D.K.; Biel, J.P.

    1996-07-01

    A catalytic converter thermal management system (TMS) using variable-conductance vacuum insulation and phase-change thermal storage can maintain the converter temperature above its operating temperature for many hours, allowing most trips to begin with minimal ``cold-start`` emissions. The latest converter TMS prototype was tested on a Ford Taurus (3.0 liter flex-fuel engine) at Southwest Research Institute. Following a 24-hour soak, the FTP-75 emissions were 0.031, 0.13, and 0.066 g/mile for NMHC, CO, and NOx, respectively. Tests were also run using 85% ethanol (E85), resulting in values of 0.005, 0.124, and 0.044 g/mile, and 0.005 g/mile NMOG. Compared to the baseline FTP levels, these values represent reductions of 84% to 96% for NMHC, NMOG, and CO.

  1. The use of Phoenics in the design of catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Luoma, M. [Kemira Metalkat Oy, Oulu (Finland); Smith, A.G. [S and C Thermofluids Ltd, Bath (United Kingdom)

    1996-12-31

    Manufacturers of automotive catalytic converters are constrained to design a system which is mechanically reliable, puts low back pressure on the engine, has adequate conversion performance, is low cost and of minimum size. In recent years, computational fluid dynamics (CFD) has been widely examined as a means of predicting the performance of catalytic converters to aid with the design process. Kemira Metalkat and S and C Thermofluids have put together and developed a number of existing CFD techniques in order to create a tool which is integrated within the design process. PHOENICS is used in the heart of the system in order to produce predictions of transient (light-off) and steady state catalyst performance. Grid generation tools have been provided to allow simplified and rapid geometry definition with suitable integration (via FEMGEN) within other parts of the catalyst design process. Simplified input techniques have been provided along with associated translators to create specification of the model for PHOENICS. Post-processing software has been provided through FEMVIEW to allow visualisation of catalyst monolith variables and transient performance animation. The whole system is controlled via a menu. The system have been use to study the effects of the catalyst design parameters on the converter performance. The results obtained using the system have so far been more qualitative than quantitative. However, validation studies have been carried out to check pressure drop prediction. A new model for the pressure drop over a metallic monolith has been developed. (author)

  2. Optimization of the packing design for manifold catalytic converter application

    Energy Technology Data Exchange (ETDEWEB)

    Kil, J.; Yeo, G.

    1996-09-01

    A preconverter is an essential component of the new vehicle exhaust system for the achievement of tightened emission standards. To meet those standards, the Manifold Catalytic Converter (MCC) system has been developed in the Hyundai Motor Company (HMC). Unfortunately, the conventional MCC is no longer a suitable design for the exhaust gas treatment of the newly developed high performance engine since it cannot withstand the engine`s exhaust temperature, vibration, pressure pulsation, and many other severe conditions. This paper is focused on a failure-mode analysis and new packing designs for the MCC application through a series of durability tests.

  3. Reducing cold-start emissions by catalytic converter thermal management

    Energy Technology Data Exchange (ETDEWEB)

    Burch, S D; Potter, T F; Keyser, M A [National Renewable Energy Lab., Golden, CO (United States); Brady, M J; Michaels, K F [Chrysler Corp. (United States)

    1995-01-01

    Vacuum insulation and phase-change thermal storage have been used to enhance the heat retention of a prototype catalytic converter. Storing heat in the converter between trips allows exhaust gases to be converted more quickly, significantly reducing cold-start emissions. Using a small metal hydride, the thermal conductance of the vacuum insulation can be varied continuously between 0.49 and 27 W/m{sup 2}K (R-12 to R-0.2 insulation) to prevent overheating of the catalyst. A prototype was installed in a Dodge Neon with a 2.0-liter engine. Following a standard preconditioning and a 23-hour cold soak, an FTP (Federal Test Procedure) emissions test was performed. Although exhaust temperatures during the preconditioning were not hot enough to melt the phase-change material, the vacuum insulation performed well, resulting in a converter temperature of 146{degrees}C after the 23-hour cold soak at 27{degrees}C. Compared to the same converter at ambient conditions, overall emissions of CO and HC were reduced by 52 % and 29 %, to 0.27 and 0.037 g/mile, respectively. The maximum converter temperature during the FTP cycle was 720{degrees}C. This limited testing was performed with a nearly-fresh palladium-only catalyst, but demonstrates the potential of this vacuum insulation approach for emissions reduction and thermal control. Further testing is ongoing. An initial assessment of several production issues is made, including high-volume fabrication challenges, durability, and cost.

  4. Retrofit catalytic converter for wood-burning stoves

    Energy Technology Data Exchange (ETDEWEB)

    None

    1983-01-01

    The major purpose of this project was to design, fabricate, test, and evaluate a retrofit catalytic converter for woodburning stoves. In the interim between our date of application March 5, 1981 and the beginning of the grant period December 1, 1981, several such devices became commercially available. Therefore, we decided to modify the purpose and direction of our project. In summary, we designed and constructed a calorimeter room in a building located on the campus of Northern Kentucky University. We equipped this room with a woodburning stove and a metal chimney extending through the roof. We designed and constructed the appropriate instrumentation for monitoring the heat output of the stove. We observed and recorded the operating characteristics of this stove over a period of several days. We then equipped the stove with a barometric damper and repeated the experiment. We are now in the process of equipping the stove with a catalytic converter. Thus the major emphasis of the project currently is to test and evaluate several commercial retrofit devices which are purported to reduce creosote and/or increase the efficiency of a woodburning stove.

  5. Diesel NO{sub x} catalytic converter development: A review

    Energy Technology Data Exchange (ETDEWEB)

    Heimrich, M.J. [Southwest Research Inst., San Antonio, TX (United States)

    1996-07-01

    This paper summarizes the findings of several technical articles on diesel NO{sub x} catalytic converter technology. Simplified theoretical reactions for NO{sub x} removal are discussed. Currently, development of catalytic NO{sub x} control technology for diesel engines is focused on systems that incorporate fuel hydrocarbons as the chemical reducing agent. Copper- and zeolite-based catalysts have been the predominant systems studied to date, but now catalysts containing precious metals are being investigated. Observed NO{sub x} reduction efficiencies typically ranged from 10 to 30 percent on actual engine exhaust systems when exhaust hydrocarbon enrichment strategies were used. Effects of carbon monoxide, sulfur dioxide, and water on NO{sub x} reduction efficiencies are reviewed. Recommendations for future research include attempts to broaden the temperature range of efficient NO{sub x} reduction, improving hydrocarbon selectivity toward the NO{sub x} reduction reaction, and the development of a supplementary reductant delivery system suitable for transient diesel engine operation.

  6. TEC as electric generator in an automobile catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, R. [Chalmers Univ. of Technology, Goeteborg (Sweden); Holmlid, L. [Univ. of Goeteborg (Sweden). Dept. of Physical Chemistry

    1996-12-31

    Modern cars use more and more electric power due to more on-board electric systems, e.g., ABS brakes, active suspension systems, electric windows, chair adjustment systems and electronic engine control systems. One possible energy source for electricity generation is to use the waste heat from the car`s engine, which generally is as much as 80% of the total energy from the combustion of the gasoline. Maybe the best location to tap the excess heat is the Catalytic Converter (Cat) in the exhaust system or perhaps at the exhaust pipes close to the engine. The Cat must be kept within a certain temperature interval. Large amounts of heat are dissipated through the wall of the Cat. A Thermionic Energy Converter (TEC) in coaxial form could conveniently be located around the ceramic cartridge of the Cat. Since the TEC is a rather good heat insulator before it reaches its working temperature the Cat will reach working temperature faster, and the final temperature of it can be controlled better when encapsulated in a concentric TEC arrangement. It is also possible to regulate the temperature of the Cat and the TEC by controlling the electrical load of the TEC. The possible working temperatures of present and future Cats appear very suitable for the new low work function collector TEC, which has been demonstrated to work down to 470 K.

  7. Modelling of automotive catalytic converter; Modellierung von Autoabgaskatalysatoren

    Energy Technology Data Exchange (ETDEWEB)

    Mladenov, Nikolay

    2010-07-01

    This thesis focuses on the numerical modeling of monolithic converters coupling diverse gas-phase and porous media transport models and detailed heterogeneous reaction mechanisms. It investigates the impact of a wide spectrum of model parameters on the conversion rate of the catalysts using the CFD software package DETCHEM. The first part of the work presents a parameter study based on the fundamentals of the conventional laminar and recently developed turbulent converters. It has been found out that an optimization at every step of the catalytic process is required in order to increase the efficiency of the exhaust gas converters. Here, calculations with a single steady-state isothermal channel of cylindrical shape are carried out using the boundary layer approach. The simulated channel is coated by a porous washcoat layer containing platinum as an active component. The transport limitation within the washcoat is described by means of a reaction-diffusion model which accounts for the distribution of macro- and micro-pores in the porous media. The study shows that an optimization with respect to operating temperature, washcoat thickness, pore radius distribution and noble metal loading results in increased conversion of carbon monoxide and hydrocarbons. However, these parameters can be varied only in certain ranges of values due to limitations such as catalyst deactivation and manufacturing costs. Structured channels and perforated metal foils represent a further option to increase the efficiency of catalytic converters. The local turbulence effects within these constructions lead to intensification of the mass transport. In the current work, this intensification is taken into account by introducing an enhanced plug-flow model with amplified mass transfer coefficients. The second part of the thesis handles the thermal aging of three way catalysts (TWC). The applied simulation approach allows for qualitative prediction of the deactivation state along the catalyst

  8. Methane emission from automobile equipped with three-way catalytic converter while driving

    Energy Technology Data Exchange (ETDEWEB)

    Takigawa, A. [Maebashi Inst. of Technology, Dept. of Civil Engineering, Maebashi, Gunma (Japan); Matsunami, A.; Arai, N. [Nagoya Univ., Research Center for Advanced Energy Conversion, Nagoya (Japan)

    2005-03-01

    In this study, the hydrocarbon emission from a three-way catalytic converter with a gasoline engine was investigated experimentally. The results reveal that converters have lower catalytic oxidation activity for methane than the other hydrocarbons, and degradation of the catalyst with use results in a significant effect on methane emission. The maximum methane concentration in exhaust using a converter with 78,000 km use is about 100 ppm, which is 1.4 times that for a new converter. The light-off temperature of the catalytic converter for hydrocarbon oxidation also rises from 548 to 598 K with an increase in the operating age of catalytic converter from 0 to 78,000 km. The ratio of CH{sub 4} concentration to total hydrocarbon increases with increasing vehicle speed and methane emission from the fuel of regular grade is higher than that of the premium grade. (Author)

  9. Potential for recovery of cerium contained in automotive catalytic converters

    Science.gov (United States)

    Bleiwas, Donald I.

    2013-01-01

    Catalytic converters (CATCONs) are required by Federal law to be installed in nearly all gasoline- and diesel-fueled onroad vehicles used in the United States. About 85 percent of the light-duty vehicles and trucks manufactured worldwide are equipped with CATCONs. Portions of the CATCONs (called monoliths) are recycled for their platinum-group metal (PGM) content and for the value of the stainless steel they contain. The cerium contained in the monoliths, however, is disposed of along with the slag produced from the recycling process. Although there is some smelter capacity in the United States to treat the monoliths in order to recover the PGMs, a great percentage of monoliths is exported to Europe and South Africa for recycling, and a lesser amount is exported to Japan. There is presently no commercial-scale capacity in place domestically to recover cerium from the monoliths. Recycling of cerium or cerium compounds from the monoliths could help ensure against possible global supply shortages by increasing the amount that is available in the supply chain as well as the number and geographic distribution of the suppliers. It could also reduce the amount of material that goes into landfills. Also, the additional supply could lower the price of the commodity. This report analyzes how much cerium oxide is contained in CATCONs and how much could be recovered from used CATCONs.

  10. Thermal analysis and testing of a vacuum insulated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Burch, S D; Potter, T F; Keyser, M A; Benson, D K

    1994-11-01

    Based on a recent US Environmental Protection Agency (EPA) study, about 95% of all trips start after a cold-soak period of 16 hours or less. By preserving the heat in the catalyst between trips, exhaust gases could be processed without warm-up delay and without the usual cold-start emissions. Vacuum insulation and phase-change thermal storage have been incorporated into a catalytic converter design to enhance its heat-retention time. Laboratory testing of a bench-scale prototype showed that a ``light off`` temperature (above 350 C) could be maintained during a 10-hour cold soak. Design improvements currently being tested should increase this heat-retention time to more than 16 hours. The thermal conductance of the vacuum insulation will be made continuously variable to prevent overheating and excessive thermal cycling. This approach to thermal management may be more durable and less costly than quick-heat methods using electric or fuel-fired preheat catalysts.

  11. Thermal analysis and testing of a vacuum insulated catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Burch, S.D.; Keyser, M.A.; Potter, T.F.; Benson, D.K.

    1994-10-01

    Based on a recent U.S. Environmental Protection Agency (EPA) study, about 95% of all trips start after a cold-soak period of 16 hours or less. By preserving the heat in the catalyst between trips, exhaust gases could be processed without warm-up delay and without the usual cold-start emissions. Vacuum insulation and phase-change thermal storage have been incorporated into a catalytic converter design to enhance its heat-retention time. Laboratory testing of a bench-scale prototype showed that a `light off` temperature (above 350{degree}C) could be maintained during a 10-hour cold soak. Design improvements currently being tested should increase this heat-retention time to more than 16 hours. The thermal conductance of the vacuum insulation will be made continuously variable to prevent overheating and excessive thermal cycling. This approach to thermal management may be more durable and less costly than quick-heat methods using electric or fuel-fired preheat catalysts. 10 refs., 4 figs.

  12. Numerical and experimental characterizations of automotive catalytic converter internal flows

    Science.gov (United States)

    Lai, M.-C.; Lee, T.; Kim, J.-Y.; Cheng, C.-Y.; Li, P.; Chui, G.

    1992-07-01

    The three-dimensional non-reacting flow field inside a typical dual-monolith automotive catalytic converter subject to different flow and structural conditions is studied numerically and experimentally. In the numerical analysis, the monolith brick resistance is formulated by using the pressure gradient of a fully developed laminar duct-flow and is corrected for the entrance effect. This correlation is found to agree with experimental pressure drop data and is introduced as an additional source term into the governing nondimensional momentum equation within the monolith brick. Simulation results show that the level of gas flow maldistribution in the monolith depends on the inlet flow Reynolds number, the brick resistance, and the inlet pipe length and its bending angles. The flow distribution is found to be more uniform inside a monolith brick with a lower inlet flow Reynolds number, a larger brick resistance, a shorter inlet pipe, and a straight inlet pipe instead of a bent one. Point-velocity measurements using laser Doppler velocimetry and smoke-flow visualization techniques at selected flow sections are also conducted to verify the simulation results.

  13. Bioaccessibility of platinum group elements in automotive catalytic converter particulates.

    Science.gov (United States)

    Turner, Andrew; Price, Simon

    2008-12-15

    The bioaccessibilities of the platinum group elements (PGE): Rh, Pd, and Pt; and the catalyzator poison, Pb, have been determined in particles derived from milled automotive catalytic converters using a physiologically based extraction test (PBET) that simulates, sequentially, the chemical conditions encountered in the human stomach and intestine. PGE accessibility, relative to total metal concentration, was generally less than a few percent, but increased in the stomach with decreasing pH (from 4 to 1) and/or increasing chloride concentration, and with decreasing particle concentration. In most cases, bioaccessibility increased from the acidic stomach to the neutral, carbonate-rich intestine. Bioaccessibility of Pb displayed similar pH and particle concentration dependencies to PGE in the stomach, but this metal exhibited significantly greater mobilization (up to 80%) overall and a reduction in accessibility from the stomach to intestine. Reaction kinetics of PGE dissolution in the stomach at pH 2.5 were modeled using a combined surface reaction-diffusion controlled mechanism with rate constants of 0.068, 0.031, and 0.015 (microg L(-1))(-1) h(-1) for Rh, Pd, and Pt, respectively. For Pb, however, mobilization proceeded via a different mechanism whose time-dependence was fitted with an empirical, logarithmic equation. Overall, PGE bioaccessibility appeared to be controlled by dissolution rates of metallic nanoparticles in the stomach, and solubility and kinetic constraints on inorganic species (chlorides, hydroxychlorides, and carbanatochlorides) and undefined organic complexes formed in the simulated gastrointestinal tract. Further studies are required to elucidate any effects engendered by the long-term oral exposure of small quantities of these species. PMID:19174929

  14. Development and test of a new catalytic converter for natural gas fuelled engine

    Indian Academy of Sciences (India)

    M A Kalam; H H Masjuki; M Redzuan; T M I Mahlia; M A Fuad; M Mohibah; K H Halim; A Ishak; M Khair; A Shahrir; A Yusoff

    2009-06-01

    This paper presents characteristics of a new catalytic converter (catco) to be used for natural gas fuelled engine. The catco were developed based on catalyst materials consisting of metal oxides such as titanium dioxide (TiO2) and cobalt oxide (CoO) with wire mesh substrate. Both of the catalyst materials (such as TiO2 and CoO) are inexpensive in comparison with conventional catalysts (noble metals) such as palladium or platinum. In addition, the noble metals such as platinum group metals are now identified as human health risk due to their rapid emissions in the environment from various resources like conventional catalytic converter, jewelers and other medical usages. It can be mentioned that the TiO2/CoO based catalytic converter and a new natural gas engine such as compressed natural gas (CNG) direct injection (DI) engine were developed under a research collaboration program. The original engine manufacture catalytic conveter (OEM catco) was tested for comparison purposes. The OEM catco was based on noble metal catalyst with honeycomb ceramic substrate. It is experimentally found that the conversion efficiencies of TiO2/CoO based catalytic converter are 93%, 89% and 82% for NOx, CO and HC emissions respectively. It is calculated that the TiO2/CoO based catalytic converter reduces 24%, 41% and 40% higher NOx, CO and HC emissions in comparison to OEM catco respectively. The objective of this paper is to develop a low-cost three way catalytic converter to be used with the newly developed CNG-DI engine. Detailed review on catalytic converter, low-cost catalytic converter development characteristics and CNGDI engine test results have been presented with discussions.

  15. Catalytic converter applications for two stroke, spark-ignited marine engines

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Hiroaki; Isogawa, Atsushi; Matsumoto, Naoto

    1995-12-31

    When catalytic converters are used for cleansing of exhaust gas from two-stroke marine engines, new issues must be brought up in combination with prior technology. Therefore, a study was made of V6, 2600cc engine having a large volume of hydrocarbon emissions with respect to three issues: (1) To what degree seawater effects catalytic converter performance and possible countermeasures; (2) Effects attained on cleansing level and catalyst temperature; (3) Finding abatement levels for catalyst deterioration and exhaust emission output in the marine mode. It was found that physical adsorption was a significant factor in catalytic degradation resulting from direct contact with seawater. The cleansing levels obtained when a marine engine is equipped with a catalyst converter were found by clarifying the extent of effects of catalyst volume, performance and temperature. The reduction obtained in exhaust emission allowing for a deterioration factor, is shown in a catalytic converter heated to the maximum temperature of 960 C.

  16. The influence of platinum washing-out time on its recovery from used auto catalytic converters

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2014-07-01

    Full Text Available The used catalytic converters contain small amounts of precious metals. Recovery of these metals is essential for environmental and economic reasons. This work presents a method of Platinum Group Metals (PGM recovery from auto catalytic converters in which they are washed out by a liquid metal. The magneto-hydro-dynamic pump was used to force circulation of liquid metal under the influence of electromagnetic fields The influence of process time on platinum recovery was also carried out.

  17. WELD CRACK RECTIFICATION IN CATALYTIC CONVERTER BY FABRICATION OF CUSTOMIZED JIG PLATES

    OpenAIRE

    A. Vignesh; P. Kritin Ram

    2015-01-01

    The main objective of this paper is to “rectify the weld cracks by the fabrication of customized jig plates”. In the engine section of the industry, there were frequent rejections of the catalytic converters due to weld cracks. When the catalytic converter assembly line was inspected, tiny cracks in the weld were found vi sually. Then they were tested through bench magnifiers and dye penetration test for confirmation and it was confirmed to have cracks in ...

  18. Effects of Gas Velocity and Temperature on Nitric Oxide Conversion in Simulated Catalytic Converter

    OpenAIRE

    Sathaporn Chuepeng

    2012-01-01

    Problem statement: Gaseous emissions from gasoline engine such as carbon monoxide, unburned hydrocarbon and nitrogen oxides were usually reduced in three-way catalytic converter simultaneously around theoretical fuel and air combustion. Engine speed and load and other parameters were varied over a wide range of operating conditions, resulting in different exhaust gas composition and condition intake into catalytic converter. This work was studied the conversion of Nitric Oxide (NO) in exhaust...

  19. Compact catalytic converter system for future diesel emissions standards; Kompaktes Katalysatorsystem fuer kuenftige Diesel-Emissionsnormen

    Energy Technology Data Exchange (ETDEWEB)

    Harth, Klaus [BASF Corporation, Iselin, NJ (United States)

    2012-09-15

    The Euro 6 emissions standard for diesel passenger cars will broaden the application of exhaust aftertreatment systems that use selective catalytic reduction. This will mean a further increase in the volume and complexity of the exhaust aftertreatment system. BASF has developed a compact integrated catalytic converter that combines the functions of particulate filtration and NO{sub x} reduction in a single unit. (orig.)

  20. Reversing flow catalytic converter for a natural gas/diesel dual fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, E.; Checkel, M.D. [Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Hayes, R.E. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering; Alberta Univ., Edmonton, AB (Canada). Dept. of Mechanical Engineering; Zheng, M.; Mirosh, E. [Alternative Fuel Systems Inc., Calgary, AB (Canada)

    2001-07-01

    An experimental and modelling study was performed for a reverse flow catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter had a segmented ceramic monolith honeycomb substrate and a catalytic washcoat containing a predominantly palladium catalyst. A one-dimensional single channel model was used to simulate the operation of the converter. The kinetics of the CO and methane oxidation followed first-order behaviour. The activation energy for the oxidation of methane showed a change with temperature, dropping from a value of 129 to 35 kJ/mol at a temperature of 874 K. The reverse flow converter was able to achieve high reactor temperature under conditions of low inlet gas temperature, provided that the initial reactor temperature was sufficiently high. (author)

  1. Demonstration of a Catalytic Converter Using a Lawn Mower Engine

    Science.gov (United States)

    Young, Mark A.

    2010-01-01

    Catalytic conversion is an important tool in environmental-remediation strategies and source removal of pollutants. Because a catalyst is regenerated, the chemistry can be extremely effective for conversion of undesirable pollutant species to less harmful products in situations where the pollutants have accumulated or are being continuously…

  2. SCR-catalytic converter technology using urea for industrial and thermal power plants. SCR-Katalysatortechnik mit Harnstoff fuer Industrie- und Heizkraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Hartenstein, A. (H und H Innotech GmbH (Switzerland)); Mayer, A. (H und H Innotech GmbH (Switzerland))

    1994-01-01

    The subjects are dealt with in 6 chapters: 1. Fuels, pollutants, prices 2. fields of application of catalytic converter systems 3. system description of the SCR catalytic converter plant using area 4. catalytic converter reactor and applications 5. efficiencies of catalytic converter plants 6. examples and profitability. (HW)

  3. Reducing catalytic converter pressure loss with enhanced inlet-header diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Wendland, D.W.; Kreucher, J.E.; Andersen, E.

    1995-12-31

    The function of the inlet header of a catalytic converter is to diffuse the inlet exhaust flow, decreasing its velocity and increasing its static pressure with as little loss in total pressure as possible. In practice, very little diffusion takes place in most catalytic converter inlet headers because the flow separates at the interface of the pipe and the tapered section leading to the substrate. This leads to increased converter pressure loss and flow maldistribution. An improved inlet-header design called the Enhanced Diffusion Header (EDH) was developed which combines a short, shallow-angle diffuser with a more abrupt expansion to the substrate cross section. Tests conducted in room air (cold flow) and engine exhaust showed that improved inlet-jet diffusion leads to substantial reductions in converter restriction. EDH performance was not compromised by the presence of a right-angle bend upstream of the converter.

  4. Optimization of the catalytic converter internal flow by using 3D-CFD; Sanjigen nagare kaiseki ni yoru shokubai converter nai nagare no saitekika

    Energy Technology Data Exchange (ETDEWEB)

    Toi, M.; Sugiura, S. [Toyota Motor Corp., Tokyo (Japan)

    1997-10-01

    By using computational fluid dynamics and statistical quality control method, we investigated the contribution of front and rear catalytic converter cone shape for the pressure loss and the partial flow, also led the optimal terms and the predictional formulations efficiently. According to this, we can investigate the optimal position of the catalytic converter from the planning. 8 figs., 6 tabs.

  5. Time domain computational modeling of viscothermal acoustic propagation in catalytic converter substrates with porous walls

    Science.gov (United States)

    Dickey, N. S.; Selamet, A.; Miazgowicz, K. D.; Tallio, K. V.; Parks, S. J.

    2005-08-01

    Models for viscothermal effects in catalytic converter substrates are developed for time domain computational methods. The models are suitable for use in one-dimensional approaches for the prediction of exhaust system performance (engine tuning characteristics) and radiated sound levels. Starting with the ``low reduced frequency'' equations for viscothermal acoustic propagation in capillary tubes, time domain submodels are developed for the frequency-dependent wall friction, frequency-dependent wall heat transfer, and porous wall effects exhibited by catalytic converter substrates. Results from a time domain computational approach employing these submodels are compared to available analytical solutions for the low reduced frequency equations. The computational results are shown to agree well with the analytical solutions for capillary geometries representative of automotive catalytic converter substrates.

  6. Thermal reliability and performance improvement of close-coupled catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Hijikata, Toshihiko; Kurachi, Hiroshi; Katsube, Fumio [NGK Insulators, Ltd., Nagoya (Japan); Honacker, H. van

    1996-09-01

    This paper proposes a high temperature catalytic converter design using a ceramic substrate and intumescent matting. It also describes the improvement of converter performance using an advanced thin wall ceramic substrate. Due to future tightening of emission regulations and improvement of fuel economy, higher exhaust gas temperatures are suggested. Therefore, reduction of thermal reliability of an intumescent mat will be a concern because the catalytic converter will be exposed to high temperatures. For this reason, a new design converter has been developed using a dual cone structure for both the inlet and outlet cones. This minimizes heat conduction through the cone and decreases the temperature affecting the mat area. This design converter, without the use of a heat-shield, reduces the converter surface temperature to 441 C despite a catalyst bed temperature of 1,050 C. The long term durability of the converter is demonstrated by the hot vibration test. Since the new design converter does not need a heat-shield, the catalyst diameter can be enlarged by the width of the air gap used in the current design converter. By using an advanced thin wall ceramic substrate, such as 0.11 mm/620 kcpsm (4 mil/400 cpsi), it is possible to improve emission performance and pressure drop compared with the conventional 0.16 mm/620 kcpsm (6 mil/400 cpsi) ceramic substrate.

  7. Raising i.c. engine catalytic converter temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, T.J.

    1994-10-19

    The engine when cold has delayed completion of combustion and advance of the exhaust event. Combustion of the exhaust gases is completed within the exhaust system in order to raise the temperature of the catalytic convertor. An ECV receives engine speed, load and temperature inputs and controls ignition timing, and/or the injection timing of part or all the fuel, and/or exhaust recirculation, and/or the number of inlet valves per cylinder and/or the number of spark plugs per cylinder which are operative and the timing of exhaust valve closure or the complete exhaust event in a four-stroke engine or the exhaust port geometry in a two-stroke engine. An afterburner may be provided upstream of the convertor. (UK)

  8. Study on the thermal deactivation of motorcycle catalytic converters by laboratory aging tests.

    Science.gov (United States)

    Chen, Yi-Chi; Chen, Lu-Yen; Yu, Yi-Hsien; Jeng, Fu-Tien

    2010-03-01

    Catalytic converters are used to curb exhaust pollution from motorcycles in Taiwan. A number of factors, including the length of time the converter is used for and driving conditions, affect the catalysts' properties during periods of use. The goal of this study is to resolve the thermal deactivation mechanism of motorcycle catalytic converters. Fresh catalysts were treated under different aging conditions by laboratory-scale aging tests to simulate the operation conditions of motorcycle catalytic converters. The aged catalysts were characterized by analytical techniques in order to provide information for investigating deactivation phenomena. The time-dependent data of specific surface areas were subsequently used to construct kinetics of sintering at the specific temperature. According to the analytical results of the catalysts' properties, the increase in aging temperature causes an increase in pore size of the catalysts and a decrease in the specific surface area. The aged catalysts all exhibited lower performances than the fresh ones. The reduction in catalytic activity is consistent with the reduction in the loss of specific surface area. The finding of catalytic properties' dependence on temperature is consistent with the thermally activated theory. In contrast, the effect of the aging time on the specific surface area was only significant during the initial few hours. The high correlation between specific surface areas measured by the Brunauer-Emmett-Teller (BET) method and predicted by the constructed model verifies that the prediction models can predict the sintering rate reasonably under the aging conditions discussed in this study. As compared to automobile catalytic converters, the differences of structures and aging conditions are made less obvious by the deactivation phenomena of motorcycles.

  9. Laboratory data for three-way catalytic converter modelling

    Energy Technology Data Exchange (ETDEWEB)

    Schweich, D. [Laboratoire de Genie des Procedes Catalytiques, Centre National de la Recherche Scientifique CNRS, Villeurbanne Cedex (France)

    1995-12-31

    Numerical simulations could be advantageously substituted for some expensive experiments with an engine bench. However, the reliability of the numerical results depends on the assumptions made and on the quality of the physical and chemical parameters involved in the model. Converter models work well for specified experimental conditions, but there is no decisive proof of their predictive ability in a wide range of conditions. This is because four important topics deserve further attention: kinetics, external heat and mass transfer processes, internal diffusion in the wash-coat layer, and flow distribution in the monolith. The experimental and interpretation problems related to these topics are reviewed. Kinetic expressions are probably the most crucial data for model reliability. These data are certainly different from one catalyst to the other. However, the reactions are the same, and the catalyst formulations are similar. This suggests that the structures of the rate expressions are probably independent of the catalyst, whereas the parameters are dependent. Elucidating the structure of the rate expressions at steady state, estimating the time constants of transient surface processes and reversible poisoning, knowing whether internal diffusion is a limiting process would be more significant contributions than accumulating light-off curves obtained with complex mixtures. Although these curves are technically meaningful, they cannot be interpreted from a scientific point of view, especially when the reactor behaviour is not well controlled. The second challenge concerns hydrodynamic data in commercial converters. The `flow distribution index` of Wendland and Matthes (1986) and Bella et al. (199l) is a first approach to the problem. However, further work is necessary to correlate this index to the operating conditions. As long as flow maldistribution is not accounted for in the models, simulation of vehicle tests will not be reliable. 8 figs., 19 refs., 1 appendix

  10. Low temperature dynamic characteristics of a three-way catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Balenovic, M.; Backx, A.C.P.M. [Technische Univ. Eindhoven (Netherlands). Dept. of Electrical Engineering; Harmsen, J.M.A.; Hoebink, J.H.B.J. [Technische Univ. Eindhoven (Netherlands). Lab. of Chemical Reactor Engineering

    2001-07-01

    A mathematical model of a three-way catalytic converter based on a detailed chemical kinetic model has been created mainly to analyze the converter's dynamic behavior at low temperatures. The light-off process of the converter is analyzed in detail. Competition of species for empty noble metal surface determines the light-off characteristic, as inhibition processes increase light-off temperatures of some exhaust gas components in the complete exhaust mixture. Perturbations of the exhaust gas mixture around stoichiometry can in certain conditions decrease the effect of inhibition and lower the light-off temperature for some exhaust components. (orig.)

  11. Low temperature dynamic characteristics of a three-way catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Balenovic, M.; Backx, A.C.P.M. [Eindhoven University of Technology (Netherlands). Dept. of Electrical Engineering; Harmsen, J.M.A.; Hoebink, J.H.B.J. [Eindhoven University of Technology (Netherlands). Laboratory of Chemical Reactor Engineering

    2001-07-01

    A mathematical model of a three-way catalytic converter based on a detailed chemical kinetic model has been created mainly to analyze the converter's dynamic behavior at low temperatures. The light-off process of the converter is analyzed in detail. Competition of species for empty noble metal surface determines the light-off characteristic, as inhibition processes increase light-off temperatures of some exhaust gas components in the complete exhaust mixture. Perturbations of the exhaust gas mixture around stoichiometry can in certain conditions decrease the effect of inhibition and lower the light-off temperature for some exhaust components. (author)

  12. Development of a model-based controller for a three-way catalytic converter

    NARCIS (Netherlands)

    Bie, T. de; Balenovic, M.; Backx, T.

    2002-01-01

    The performance of a three-way catalytic converter under transient operation can be improved by controlling the level of oxygen stored on ceria at some optimal level. A model-based controller with the model estimating the level of ceria coverage by oxygen, can achieve this goal. A simple, dynamic mo

  13. DuraFoil{sup TM} ICR-a new material for catalytic converter substrates

    Energy Technology Data Exchange (ETDEWEB)

    Sukonnik, I.M.; Chang, S.; Jha, B. [Texas Instruments, Inc., Attleboro, MA (United States)

    1997-12-31

    A new type of FeCrAl material for catalytic converter substrate applications, DuraFoil{sup TM} ICR, has been developed by solid state bonding of strip layers of steel and aluminum. Such clad material is further rolled to intermediate gauge and then subjected to a thermal in situ reaction to form a solid solution material. Such monolithic material is subsequently thermomechanically processed to foil gauges. The combination of roll bonding followed by thermo-mechanical processing to produce FeCrAl foil for metallic catalytic converter substrate offers many metallurgical and economic advantages over conventional ingot metallurgy practice. The fact that thermal diffusion was performed at the intermediate gauge prior to reaching the final foil thickness gives material properties for use in the wider design range of catalytic converters. In its simplest form, the requirements for a catalytic converter substrate (foil material) are dictated by four major factors: oxidation resistance; shape stability; formability (applicable ductility); and compatibility with typical substrate processing technologies such as brazing and washcoating. To this end, the microstructures, mechanical properties, chemical homogeneity, surface chemistry and morphology of two DuraFoil{sup TM} new grades foil materials, i.e., ICR-H (hard) and ICR-F (soft), were characterized. This study has shown those superior properties, desirable formability can be achieved from diffusion-made material. (orig.)

  14. Modeling and Model-Based Control of a Three-Way Catalytic Converter

    Energy Technology Data Exchange (ETDEWEB)

    Balenovic, M.

    2002-03-25

    The subject of the research presented in this thesis was the development of new control strategies for automotive three-way catalytic converters in order to fulfill future ultra-low exhaust emission standards. The goal was to develop a model-based control strategy that can reduce the emissions under highly dynamic operation of the process, i.e.city driving. Also a possible improvement of the catalyst light-off (reduction of the temperature needed for the converter to become operational) has been studied. The main contribution of the thesis is the development of a model-based controller on the basis of information extracted from the first principle modeling of the converter. The three main parts of the research were: development of the rigorous first principle model of the catalytic converter; development of the control-oriented model of the catalytic converter and connecting it with the engine model; development and testing of the novel model-based controller by both simulations and experiments.

  15. Novel catalytic converter for natural gas powered diesel engines to meet stringent exhaust emission regulations

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, M.; Mirosh, E.A. [Alternative Fuel Systems Inc. (Canada); Matros, Yu.S.; Bunimovich, G.A.; Strots, V.O. [Matros Technologies Inc. (United States); Sallamie, N.; Checkel, M.D. [Alberta Univ. (Canada); Windawi, H. [Johnson Matthey (United States)

    1998-12-31

    The implementation of stringent exhaust emission regulations has led to the development of natural gas powered dual fuel systems with electronic multiport injection. The high compression ratio of the baseline diesel engine was maintained to keep the high thermal efficiency of diesel cycles. The dual fuel system is mainly powered by natural gas and ignited by a diesel pilot. Extensive experimental results indicate that the diesel dual fuel system provides simultaneous reductions in NO{sub x} and particulate emissions. The system also has low exhaust THC and CO under heavy-duty operations. With the combined use of exhaust gas recirculation and catalytic converter, low emission operation has been extended to a larger range, from medium to full loads for all testing speeds. However, conventional converters exhibit poor conversion efficiency at low engine loads due to the low exhaust temperature levels. This leads to increased exhaust emissions during low load operations, especially for the non-reactive hydrocarbons, specifically, methane. To solve this problem, a novel automotive exhaust gas aftertreatment system - the reversing flow catalytic converter - has been developed. The prototype Reversing Flow Converter (RFC) consists of a diversion flow valve and a catalytic monolith converter. The diversion valve periodically re-directs the engine exhaust flow through the catalyst in alternative directions. The duration of flow in each direction is determined by engine operating conditions to obtain an ideal temperature profile along the axis of the monolith. The catalytic converter was designed to have high methane conversion efficiency. Associated techniques, such as retarding fuel injection, exhaust gas recirculation, and the variation of diesel pilot to natural gas ratio, can be used to raise exhaust temperature and bring the catalytic converter to light-off temperatures quicker. Engine dynamometer tests showed that CO conversion rate was above 95% and CH{sub 4

  16. Flow Field Measurement in Catalytic Converter Comparison with Computational Fluid Dynamics Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Seoungchool; Jang, Sungkuk [Halla Univ., Wonju (Korea, Republic of)

    2014-03-15

    The efficiency of a catalytic converter depends on the flow distribution across a system's chemically active substrate. If irregularities or non-uniform flow patterns exist, the system's conversion efficiency decreases, whereas the manufacturing cost increases. Therefore, it is important to analyze the internal flow of a catalytic converter. In this study, flow pattern measurements along the minor axis were recorded at the mid and exit planes of a ceramic honeycomb catalytic converter at flow rates of 37.8 ι/s and 94.4 ι/s. Flow distributions of the measurement plans were compared with an automotive company's computed velocity profiles. Measurements along the minor axis showed uneven velocity profiles. The υ-velocity components between the honeycomb bricks were small but somewhat erratic opposite the intake side of the converter, however, they became flatter in measurements recorded near the intake entrance. For almost all velocity values, the computer model suggested velocities greater than the measured values.

  17. Catalytic converter technologies for future exhaust emission standards; Katalysatortechnologien fuer zukuenftige Abgasgrenzwerte

    Energy Technology Data Exchange (ETDEWEB)

    Kueper, P.F. [Porsche (F.) AG, Weissach (Germany); Bruestle, C. [Porsche (F.) AG, Weissach (Germany)

    1994-12-31

    Due to the Californian exhaust gas legislation for the period after 1995 and the expected tightening of the European standards, new impulses were given to increase the effectiveness of the exhaust aftertreatment. A list is presented which attempts to give an overview of the question of which exhaust aftertreatment or which additional devices must be applied in order to meet the future exhaust emission standards. The ageing of the catalytic converters has been taken into account. The actual exhaust emission standards are met with the conventional systems. Additional measurements such as secondary ventilation are necessary for TLEV. In order to achieve LEV additional measurements such as lighter exhaust gas systems and modifications of the cold starting and warm-up parameters could be sufficient. There are two different systems which meet the ULEV standards: 1. Active systems with an external energy supply for heating up the main or a starting catalytic converter. These systems do not necessarily require a catalytic converter position close to the engine. 2. Passive systems with switchable starting catalytic converters and without an external energy supply for heating up the main catalytic converter. It offers an alternative to the active systems. Furthermore the switchable catalytic converter suggested by the company Porsche can be applied in charged engines. A further reduction of HC-emission will be achieved by the combination of the two systems mentioned above with HC absorbing and desorbing systems. (orig.) [Deutsch] Durch die kalifornische Abgasgesetzgebung fuer die Zeit nach 1995 und die zu erwartenden Verschaerfungen der europaeischen Grenzwerte wurden neue Entwicklungsimpulse zur Steigerung der Effektivitaet der Abgasnachbehandlung ausgeloest. Eine Antwort auf die Frage, welche Abgasnachbehandlungssysteme bzw. welche Zusatzeinrichtungen zur Erfuellung der zukuenftigen Abgasgrenzwerte eingesetzt werden muessen, wird nachfolgend versucht aufzulisten, wobei die

  18. Development of a para-orthohydrogen catalytic converter for a solid hydrogen cooler

    Science.gov (United States)

    Nast, T. C.; Hsu, I. C.

    1984-01-01

    Design features of a tested catalytic converter for altering vented cryogenic parahydrogen used as a coolant on spacecraft into a para-ortho equilibrium for channeling to other cooling functions are described. The hydrogen is expected to be stored in either liquid or solid form. A high surface area Ni-on-Si catalyst was selected for tests at an operating pressure of 2 torr at a ratio of 1000 gr catalyst for a gr/sec hydrogen flow. Cylindrical and radial flow geometries were tried and measurements centered on the converter efficiencies at different operating temperatures when the converter was placed in the vent line of the H2 cooler. Efficiencies ranging from 10-100 percent were obtained for varying flow rates. Further testing is necessary to characterize the converter performance under a wider range of operating temperatures and environments.

  19. Ultra trace analysis and mobility of palladium emissions from automotive catalytic converters

    OpenAIRE

    Schindl, Roland

    2015-01-01

    Palladium (Pd) is emitted as particles and nanoparticles in considerable amounts from automotive catalytic converters along with the exhaust fume. In the environment Pd nanoparticles may be coated by small organic molecules or dissolve to Pd(II) species. Transformation and mobility of Pd in nature is not well understood yet and have to be investigated due to possible environmental and health risks. In the first part of this thesis a method for the determination of Pd in urban samples, suc...

  20. A non-stationary problem coupling PDEs and ODEs modelizing an automotive catalytic converter

    OpenAIRE

    Hoernel, J. -D.

    2005-01-01

    In this paper we prove the existence and uniqueness of the solution of a non-stationary problem that modelizes the behaviour of the concentrations and the temperature of gases going through a cylindrical passage of an automotive catalytic converter. This problem couples parabolic partial differential equations in a domain with one parabolic partial differential equation and some ordinary differential equations on a part of its boundary.

  1. Fuzzy logic for burner, solar boiler and catalytic converter; Brander, zonneboiler en katalysator vaag geregeld

    Energy Technology Data Exchange (ETDEWEB)

    Voorter, P.H.C.

    1995-05-01

    The application of fuzzy logic in the process control of a cement furnace at a Dutch cement industry (Enci in Maastricht) proved to be successful: the production increased by 4% and the energy consumption was reduced by 3% per ton product. Fuzzy logic can also be used in smaller energy equipment. Applications in a burner of a central heating boiler, a solar water heater and a catalytic converter in a motorcycle are discussed. 5 figs., 1 tab., 2 refs.

  2. Optimizing fuel consumption and pollutant emissions of gasoline-HEV with catalytic converter

    OpenAIRE

    Michel, Pierre; Charlet, Alain; Colin, Guillaume; Chamaillard, Yann; Bloch, Gérard; Nouillant, Cédric

    2016-01-01

    International audience Because of more and more stringent vehicle emission standards, Hybrid Electric Vehicles (HEV) are developed. Gasoline-HEV are equipped with 3-Way Catalytic Converter (3WCC). So the energy management systems of such vehicles , which must reduce not only fuel consumption, but also vehicle pollutant emissions, have to consider the 3WCC heating. A pollutant constrained energy management strategy is presented. A 3WCC multi-0D model is built from physical equations, with a...

  3. Modelling three-way monolithic catalytic converter. Comparison between simulation and experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Siemund, S.; Schweich, D.; Leclerc, J.P.; Villermaux, J. [Centre National de la Recherche Scientifique CNRS, LSGC, Ecole Nationale Superieure des Industries Chimiques ENSIC, Nancy (France)

    1995-12-31

    A two-dimensional model for the three-way catalytic converter is presented. The proposed model with the necessary simplifying assumptions are represented. Then the simulation results and experimental data, which are obtained by engine test bench, are compared. By adjusting the kinetic parameters a good agreement is obtained for the temperature evolution, a less good agreement for the conversion. Finally, the necessary improvements are briefly discussed. 9 figs., 18 refs.

  4. Numerical analysis of thermal and flow characteristics for an optimum design of automotive catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, S.J. [Hanyang University Graduate School, Seoul (Korea); Kim, W.S. [Hanyang University, Seoul (Korea)

    1999-07-01

    In the present work, the effect of a flow maldistribution on the thermal and conversion response of a monolith catalytic converter is investigated. To achieve this goal, a combined chemical reaction and multi-dimensional fluid dynamic mathematical model has been developed. The present results show that flow uniformity within the monolith brick has a great impact on light-off performance of the catalytic converter. In the case of lower flow uniformity, large portions of the monolith remain cold due to locally concentrated high velocities and CO, HC are unconverted during warm-up period, which leads to retardation of light-off. It has been also found that the heat-up pattern of the monolith is similar to the flow distribution profile, in the early stage of the reaction. It may be concluded that flow maldistribution can cause a significant retardation of the light-off and hence can eventually worsen the conversion efficiency of automotive catalytic converter. (author). 31 refs., 11 figs., 2 tabs.

  5. Modification of Surface Roughness and Area of FeCrAl Substrate for Catalytic Converter using Ultrasonic Treatment

    OpenAIRE

    Yanuandri Putrasari; P Untoro; Sulaiman Hasan; Naili Huda; Darwin Sebayang

    2012-01-01

    Surface roughness and area play important role especially in deposition and reaction of the catalyst in the catalytic converter substrate. The aim of this paper is to show the modification of surface roughness and area of FeCrAl substrate for catalytic converter using ultrasonic method. The method was conducted by agitating the FeCrAl in 10 minutes 35 kHz ultrasonic cleaning bath. The  surface roughness, morphology, and chemical components of FeCrAl catalytic converter substrate after ultraso...

  6. Effects of Gas Velocity and Temperature on Nitric Oxide Conversion in Simulated Catalytic Converter

    Directory of Open Access Journals (Sweden)

    Sathaporn Chuepeng

    2012-01-01

    Full Text Available Problem statement: Gaseous emissions from gasoline engine such as carbon monoxide, unburned hydrocarbon and nitrogen oxides were usually reduced in three-way catalytic converter simultaneously around theoretical fuel and air combustion. Engine speed and load and other parameters were varied over a wide range of operating conditions, resulting in different exhaust gas composition and condition intake into catalytic converter. This work was studied the conversion of Nitric Oxide (NO in exhaust gas catalytic converter affected by gas velocity and inlet temperature using numerical modeling. Approach: The simulation was based on a one-dimensional time-dependent model within a single monolith channel of the converter. Upon certain assumptions, the study was considered heterogeneous combustion reaction between gas and solid phases based on lumped kinetic reactions. In this study, constants and variables used for mass and heat transfers were dependent on gas or solid phase temperature and mole fraction. Finite difference scheme incorporated with the generated computer code was established for solving species and energy balances within gas and solid phases. Results: The NO conversion was increased with transient period in initial and reached steady state at different values. The lower inlet gas temperature was resulted in lesser NO conversion at the same inlet NO concentration and gas velocity. The light-off temperatures were up to 520 K and a sudden rise in NO conversion was from 550-605 K and decreasing onwards, generating working temperature window. NO conversion increased throughout the catalyst bed from the inlet and the conversion decreased as the gas velocity increased. Conclusion/Recommendations: Gas space velocity and gas temperature intake to the converter affected the NO conversion over the time and the axial distance from the catalyst bed inlet. The numerical results have summarily demonstrated a good approximation compared to experimental

  7. Experimental study of a reverse flow catalytic converter for a duel fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.; Checkel, M. D. [Alberta Univ., Dept. of Mechanical Engineering, Edmonton, ANB (Canada); Hayes, R. E. [Alberta Univ., Dept, of Chemical and Materials Engineering, Edmonton, AB, (Canada)

    2001-08-01

    Performance of a reverse flow catalytic converter for a methane/diesel dual fuel engine is evaluated under steady and transient engine conditions. The converter is of the monolith honeycomb type with palladium catalyst washcoat. Results of the reverse flow converter's performance was found to be superior for several steady state engine operations when compared to unidirectional flow operation. In transient operations following a step change in engine operating conditions, reverse flow was found to be better than unidirectional flow when the change in engine operation was such as to reduce the exhaust gas temperature. When exhaust gas temperature was increased, reverse flow decreased the rate of increase in the reactor temperature. Testing was done using the transient Japanese 6-Mode tests. Best results were achieved with a switch time in the five seconds to fifteen seconds range. 31 refs., 9 tabs., 24 figs.

  8. Calculating the rate of exothermic energy release for catalytic converter efficiency monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Hepburn, J.S.; Meitzler, A.H. [Ford Motor Co., Dearborn, MI (United States)

    1995-12-31

    This paper reports on the development of a new methodology for OBD-II catalyst efficiency monitoring. Temperature measurements taken from the center of the catalyst substrate or near the exterior surface of the catalyst brick were used in conjunction with macroscopic energy balances to calculate the instantaneous rate of exothermic energy generation within the catalyst. The total calculated rate of exothermic energy release over the FTP test cycle was within 10% of the actual or theoretical value and provided a good indicator of catalyst light-off for a variety of aged catalytic converters. Normalization of the rate of exothermic energy release in the front section of the converter by the mass flow rate of air inducted through the engine was found to provide a simple yet practical means of monitoring the converter under both FTP and varying types of road driving.

  9. Condition in ci engine’s exhaust pipe in light of application nox sensor to determine of catalytic converter efficiency

    OpenAIRE

    Rychter, M.

    2010-01-01

    The development of a catalytic converter required an analysis of selected physical parameters of the supports. This resulted from the necessity to assume given parameters of the supports applied in the tests in exhaust gas environment in the CI engines. An analysis of ionic conductors which constitute the basic solution in voltage sensors providing signals through NOx electrocatalysis. The aim of this paper is to determine the basis for the monitoring of catalytic converters in compression ig...

  10. Converting Light Energy to Chemical Energy: A New Catalytic Approach for Sustainable Environmental Remediation

    Science.gov (United States)

    2016-01-01

    We report a synthetic approach to form cubic Cu2O/Pd composite structures and demonstrate their use as photocatalytic materials for tandem catalysis. Pd nanoparticles were deposited onto Cu2O cubes, and their tandem catalytic reactivity was studied via the reductive dehalogenation of polychlorinated biphenyls. The Pd content of the materials was gradually increased to examine its influence on particle morphology and catalytic performance. Materials were prepared at different Pd amounts and demonstrated a range of tandem catalytic reactivity. H2 was generated via photocatalytic proton reduction initiated by Cu2O, followed by Pd-catalyzed dehalogenation using in situ generated H2. The results indicate that material morphology and composition and substrate steric effects play important roles in controlling the overall reaction rate. Additionally, analysis of the postreacted materials revealed that a small number of the cubes had become hollow during the photodechlorination reaction. Such findings offer important insights regarding photocatalytic active sites and mechanisms, providing a pathway toward converting light-based energy to chemical energy for sustainable catalytic reactions not typically driven via light.

  11. Effects of a catalytic converter on PCDD/F, chlorophenol and PAH emissions in residential wood combustion.

    Science.gov (United States)

    Kaivosoja, T; Virén, A; Tissari, J; Ruuskanen, J; Tarhanen, J; Sippula, O; Jokiniemi, J

    2012-07-01

    Catalytic converters can be used to decrease carbon monoxide, organic compounds and soot from small-scale wood-fired appliances. The reduction is based on the oxidation of gaseous and particulate pollutants promoted by catalytic transition metal surfaces. However, many transition metals have also strong catalytic effect on PCDD/F formation. In this study birch logs were burned in a wood-fired stove (18 kW) with and without a catalytic converter with palladium and platinum as catalysts. PCDD/F, chlorophenol and PAH concentrations were analyzed from three phases of combustion (ignition, pyrolysis and burnout) and from the whole combustion cycle. PCDD/F emissions without the catalytic converter were at a level previously measured for wood combustion (0.15-0.74 ng N m(-3)). PAH emissions without the catalytic converter were high (47-85 mg N m(-3)) which is typical for batch combustion of wood logs. Total PAH concentrations were lower (on average 0.8-fold), and chlorophenol and PCDD/F levels were substantially higher (4.3-fold and 8.7-fold, respectively) when the catalytic converter was used. Increase in the chlorophenol and PCDD/F concentrations was most likely due to the catalytic effect of the platinum and palladium. Platinum and palladium may catalyze chlorination of PCDD/Fs via the Deacon reaction or an oxidation process. The influence of emissions from wood combustion to human health and the environment is a sum of effects caused by different compounds formed in the combustion. Therefore, the usage of platinum and palladium based catalytic converters to reduce emissions from residential wood combustion should be critically evaluated before wide-range utilization of the technology. PMID:22397840

  12. Different in vivo functions of the two catalytic domains of angiotensin converting enzyme (ACE)

    OpenAIRE

    Bernstein, Kenneth E.; Shen, Xiao Z.; Gonzalez-Villalobos, Romer A.; Billet, Sandrine; Okwan-Duodu, Derick; Ong, Frank S.; Fuchs, Sebastien

    2010-01-01

    Angiotensin converting enzyme (ACE) can cleave angiotensin I, bradykinin, neurotensin and many other peptide substrates in vitro. In part, this is due to the structure of ACE, a protein composed of two independent catalytic domains. Until very recently, little was known regarding the specific in vivo role of each ACE domain, and they were commonly regarded as equivalent. This is not true, as shown by mouse models with a genetic inactivation of either the ACE N- or C-domains. In vivo, most ang...

  13. Catalytic converter design and materials. (Bibliography from the global mobility database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  14. Catalytic converter design and materials. (Bibliography from the Global Mobility database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains a minimum of 222 citations and includes a subject term index and title list.)

  15. Catalytic converter design and materials. (Bibliography from the Global Mobility database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  16. Catalytic converter design and materials. (A bibliography from the Global Mobility database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains a minimum of 220 citations and includes a subject term index and title list.)

  17. Methods for the determination of platinum group elements originating from the abrasion of automotive catalytic converters

    Science.gov (United States)

    Bencs, László; Ravindra, Khaiwal; Van Grieken, René

    2003-10-01

    Anthropogenic emission of platinum group elements (PGEs) from the abrasion of automotive catalytic converters into the environment has significantly increased. However, the concentration level of these PGEs (i.e. Pd, Pt, Rh) is still very low in the nature. Accordingly, their determination and speciation in various environmental compartments appears to be a challenging task for analytical chemists. The present review gives an overview of the analytical procedures documented in this particular field of analytical chemistry with a distinctive emphasis on spectrochemical methodology, it being the most sensitive and robust for accomplishing the above analytical task.

  18. Transient simulation of a catalytic converter for a dual fuel engine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, B.; Checkel, D. [Alberta Univ., Dept. of Mechanical Enginering, Edmonton, AB (Canada); Hayes, R. E. [Alberta Univ., Department of Chemical and Material Engineering, Edmonton, AB (Canada); Zheng, M.; Mirosh, E. [Alternative Fuel Systems Inc., Calgary, AB (Canada)

    2000-06-01

    A catalytic converter of a ceramic monolith honeycomb substrate, coated with a washcoat of catalyst and attached to a natural gas/diesel dual fuel engine was simulated and studied experimentally. The paper describes the application of one-dimensional finite element model for the transient and steady state operation. Laminar flow was approximated using a dispersed plug flow model, and chemical kinetics were simulated using LHHW (Langmuir/ Hinshelwood/ Hougan/ Watson) type expressions. Simulation results were compared with experimental results for heating and cooling cycles which resulted from speed and load changes on the engine. The comparison showed a maximum difference between the two sets of emission levels of about 10 per cent, showing that the one-dimensional model is acceptable model for this dual fuel engine converter combination. 50 refs., 3 tabs., 13 figs.

  19. Biologic effects of auto emissions. I. Exhaust from engine with and without catalytic converter.

    Science.gov (United States)

    Lee, S D; Malanchuk, M; Finelli, V N

    1976-05-01

    This paper relates to the efficacy of a catalytic converter in reducing the levels of certain pollutants emitted from an automobile engine and to the reduction and/or elimination of gross biologic damages in animals exposed to emissions from an exhaust system containing such catalysts. Groups of rats were exposed to diluted emissions from an automobile engine with and without catalyst. Concomitantly, a comparative experiment was conducted by exposing a group of rats to carbon monoxide alone (575 mg/m3). The parameters measured included hematocrit, serum LDH, GOT, and lysozyme. An elevation in hematocrit was observed in animals of the experiment run without catalyst and in those exposed to carbon monoxide; the use of the catalyst reduced the carbon monoxide levels in the exposure chambers by more than tenfold and prevented these bioeffects from occurring. Serum LDH activity was elevated in the groups of rats in the experiment conducted without catalyst, but no alternation was observed in the animals from the experiment utilizing the catalyst or in those exposed to carbon monoxide alone. The data obtained in this study showed that acute exposure to noncatalytic emissions caused significant alterations in certain biologic parameters. Conversely, the introduction of an oxidizing catalytic converter into the engine exhaust system reduced or prevented such biologic damage. PMID:58066

  20. The effect of oxygen storage capacity on the dynamic characteristics of an automotive catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Shamim, Tariq [Department of Mechanical Engineering, The University of Michigan-Dearborn, Dearborn, MI 48128-2406 (United States)

    2008-11-15

    Automotive catalytic converters, which are employed to reduce engine exhaust emissions, are subjected to highly transient conditions during a typical driving cycle. These transient conditions arise from changes in driving mode, the hysteresis and flow lags of the feedback control system, and result in fluctuations of air-fuel ratio, exhaust gas flow rates and temperatures. The catalyst performance is also strongly influenced by the oxygen storage capacity. This paper presents a computational investigation of the effect of oxygen storage capacity on the dynamic behavior of an automotive catalytic converter subjected to modulations in exhaust gases. The modulations are generated by forcing the temporal variations in exhaust gases air-fuel ratio, gas flow rates and temperatures. The study employs a single-channel based, one-dimensional, non-adiabatic model. The results show that the imposed modulations cause a significant departure in the catalyst behavior from its steady behavior, and the oxygen storage capacity plays an important role in determining the catalyst's response to the imposed modulations. Modulations and oxygen storage capacity are found to have relatively greater influence on the catalyst's performance near stoichiometric conditions. (author)

  1. Vapour Treatment Method Against Other Pyro- and Hydrometallurgical Processes Applied to Recover Platinum From Used Auto Catalytic Converters

    Institute of Scientific and Technical Information of China (English)

    Agnieszka FORNALCZYK; Mariola SATERNUS

    2013-01-01

    Today more and more cars are produced every year.All of them have to be equipped with catalytic converters,the main role of which is to obtain substances harmless to the environment instead of exhausted gases.Catalytic converters contain platinum group metals (PGM) especially platinum,palladium and rhodium.The price of these metals and their increasing demand are the reasons why today it is necessary to recycle used auto catalytic converters.There are many available methods of recovering PGM metals from them,especially platinum.These methods used mainly hydrometallurgical processes; however pyrometallurgical ones become more and more popular.The article presents results of the research mainly concerning pyrometallurgical processes.Two groups of research were carried out.In the first one different metals such as lead,magnesium and copper were used as a metal collector.During the tests,platinum went to those metals forming an alloy.In other research metal vapours were blown through catalytic converter carrier (grinded or whole).In the tests metals such as calcium,magnesium,cadmium and zinc were applied.As a result white or grey powder (metal plus platinum) was obtained.The tables present results of the research.Processing parameters and conclusions are also shown.To compare efficiency of pyrometallurgical and hydrometallurgical methods catalytic converter carrier and samples of copper with platinum obtained from pyrometallurgical method were solved in aqua regia,mixture of aqua regia and fluoric acid.

  2. Novel techniques for the synthesis of three-way catalytic converter support materials

    Science.gov (United States)

    Anyaba, Prince Nwabueze

    Current automobiles use catalytic converters, consisting of noble metals on an oxide support, to convert noxious engine exhaust pollutants into less harmful species. The development of mesoporous oxide supports with optimal pore geometries could enable these devises to decrease in size and weight and significantly reduce the metal loadings required to achieve optimal performance. Thus, in this work, I investigated a wide range of techniques for the synthesis of mesoporous oxides to determine if they could be adapted to ceria-zirconia-yttria mixed oxide (CZY) systems, which are the industry standard for the optimal oxide support for catalytic converter applications. Additionally, I compared and critically evaluated the catalytic performance of the CZY mixed oxides, which were synthesized from the various templating techniques. The catalytic performance test was broken up into two: catalyst activity test which was determined based on the light-off temperatures at which 50% conversion of the reacting species have been converted; and resistance to surface area loss under accelerated aging at heating rate of 20°C/min form 700 to 1000°C, with the final temperature being held fixed for 4 h. To date, the most cost effective methods for preparing mesoporous materials are via techniques that employ templates or structure directing agents. These templates can be divided into two groups: endo-templates (i.e., soft templates, such as surfactants, dendrimers, and block copolymers) and exo-templates (i.e., hard templates, such as porous carbons and resins). The soft templating techniques generally involve both sol-gel and templating methods, while the hard templates required no sol-gel chemistry to achieve the desired templating effect. The precursors for ceria, zirconia, and yttria used were cerium (III) nitrate hexahydrate, zirconyl nitrate, and yttrium nitrate hexahydrate, respectively. The mesoporous CZY materials that were synthesized had surface area values that were

  3. A multi-dimensional numerical method for predicting warm-up characteristic of automobile catalytic converter systems

    Energy Technology Data Exchange (ETDEWEB)

    Sugiura, Shigeki; Ijuin, Koichi; Yamada, Toshio; Yaegashi, Takehisa; Baba, Naoki

    1995-12-31

    A multi-dimensional numerical method for predicting the warm-up characteristic of automobile catalytic converter systems was developed to effectively design catalytic converter systems which achieve low tail pipe emissions with satisfactory package ability. The features of the method are: (1) consideration of the governing phenomena such as gas flow, heat transfer, and chemical reactions and (2) capability of predicting warm-up characteristic for not only the catalytic converters but also the system as a whole during emission test modes such as the USA LA-4 mode. The description of the method is presented. The experimental verifications of the method were conducted to assure the accuracy of it. The effect of design parameters such as electrically heated catalyst (EHC), high loading of noble metal and thin honeycomb wall on warm-up characteristic of the catalyst are analyzed in the paper.

  4. Modification of Surface Roughness and Area of FeCrAl Substrate for Catalytic Converter using Ultrasonic Treatment

    Directory of Open Access Journals (Sweden)

    Yanuandri Putrasari

    2012-03-01

    Full Text Available Surface roughness and area play important role especially in deposition and reaction of the catalyst in the catalytic converter substrate. The aim of this paper is to show the modification of surface roughness and area of FeCrAl substrate for catalytic converter using ultrasonic method. The method was conducted by agitating the FeCrAl in 10 minutes 35 kHz ultrasonic cleaning bath. The  surface roughness, morphology, and chemical components of FeCrAl catalytic converter substrate after ultrasonic treatment were analyzed using atomic force microscope (AFM and examined with scanning electron microscope (SEM in combination with energy dispersive X-ray spectroscopy (EDS. The ultrasonic treatment assisted with Al2O3 powders successfully increased the roughness and surface area of FeCrAl better than SiC powders. 

  5. Substrate contributions to automotive catalytic converter performance. The role of channel shape on catalyst efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Day, J.P. [Science and Technology Division, Corning Incorporated, Corning, New York (United States)

    1998-12-31

    The catalyst support plays an integral part in the performance of the automotive catalytic converter system. Although the precious metal catalyst is the primary contributor to the conversion efficiency, the substrate role is to properly distribute and support the washcoat and precious metal catalyst in order to utilize the properties of these components most fully. By optimizing the substrate properties as well as the precious metal and washcoat systems, optimum benefit from the catalyst system can be obtained. The automotive catalyst support is composed of the material and the structure. Previous papers have dealt with the materials. This paper will describe the structure of the catalyst support, specifically the channel shape, and present the structure-related heat transfer, mass transfer, and pressure drop properties for the laminar flow condition for various channel shapes. After these relationships have been established, a comparison will be made between the catalyst system performance of two of the channel shapes available commercially. 14 refs.

  6. Control of gaseous pollutants emission with EGR (exhaust gas recirculation) and catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Fernando Silva de Araujo [Faculdade de Engenharia Quimica de Lorena (FAENQUIL), SP (Brazil); Mann, Jens; Ueberschaer, Dietmar [Fachhochschule Darmstadt (Germany). Fachbereich Maschinenbau; Balestieri, Jose Antonio Perrella; Nascimento, Nazem [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia]. E-mail: ftilor@eu.ansp.br; perrella@feg.unesp.br; nazem@feg.unesp.br

    1997-07-01

    Study of gaseous pollutant emission from engine tests simulating real work conditions, using spark point manually controlled and exhaust gas recirculation in diverse proportion levels. The objective of this present work is to re-examine the potential of the EGR conception, a well-known method of combustion control, employed together electronic fuel injection and three-way catalytic converter closed-loop control at a spark ignition engine, verifying the performance characteristics and technical availability of this conception to improve pollution control and fuel economy. The pollutant emissions under operational conditions were analyzed and compared with the expected by concerning theory and real tests performed by EGR equipped engines by factory. (author)

  7. Aluminum clad ferritic stainless steel foil for metallic catalytic converter substrate applications

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.S.; Pandey, A.; Jha, B.

    1996-09-01

    A roll bonding process was developed to produce Al clad ferritic stainless steel foil for the metallic catalytic converter substrate application. Clad foils with different chemistry were produced and their properties were evaluated. Heat treatment conditions for the homogenization of clad foils were identified. This article includes results from oxidation tests and mechanical tests on as-rolled and heat treated clad foil. Results from commercial ingot metallurgy foil were also included for comparison. The oxidation weight gain study indicates that the Al content in the foils is directly related to the usable life of the foil. However, rare earth addition is necessary to improve the oxidation resistance of this material for the high temperature applications by slowing down the weight gain kinetics and thus extend the usable life of foils. The heat treated clad foil also exhibit excellent tensile ductility when compared to the ingot metallurgy foil.

  8. A theoretical study for one-dimensional modeling for VOC in a catalytic converter

    Science.gov (United States)

    Chauhan, S.; Sharma, L.; Srivastava, V. K.

    2010-07-01

    Modeling for catalytic oxidation of a volatile organic compound, acetaldehyde for the purpose of controlling tail-pipe emissions from vehicular exhaust was carried out. The model developed was one-dimensional unsteady state model, using mass and energy balance equations to predict results for acetaldehyde conversion in an adiabatic monolith operating under warm-up conditions. The equations consisted of a set of partial differential equations that are coupled and solved using Backward Implicit Scheme. Analysis of the behavior of the converter during warm up period was carried out and it was observed that the warm up was faster for a fresh catalyst and this warm up period could be reduced by introducing hot incoming exhaust gas at higher temperature.

  9. QM/MM investigation of the catalytic mechanism of angiotensin-converting enzyme.

    Science.gov (United States)

    Mu, Xia; Zhang, Chunchun; Xu, Dingguo

    2016-06-01

    Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II and degrades bradykinin and other vasoactive peptides. ACE inhibitors are used to treat diseases such as hypertension and heart failure. It is thus highly desirable to understand the catalytic mechanism of ACE, as this should facilitate the design of more powerful and selective ACE inhibitors. ACE exhibits two different active domains, the C-domain and the N-domain. In this work, we systematically investigated the inhibitor- and substrate-binding patterns in the N-domain of human ACE using a combined quantum mechanical and molecular mechanical approach. The hydrolysis of hippuryl-histidyl-leucine (HHL) as catalyzed by the N-domain of human somatic ACE was explored, and the effects of chloride ion on the overall reaction were also investigated. Two models, one with and one without a chloride ion at the first binding position, were then designed to examine the chloride dependence of inhibitor-substrate binding and the catalytic mechanism. Our calculations indicate that the hydrolysis reaction follows a stepwise general base/general acid catalysis path. The estimated mean free energy barrier height in the two models is about 15.6 kcal/mol, which agrees very well with the experimentally estimated value of 15.8 kcal/mol. Our simulations thus suggest that the N-domain is in a mixed form during ACE-catalyzed hydrolysis, with the single-chloride-ion and the double-chloride-ion forms existing simultaneously. Graphical Abstract Superposition of ACE C- and N- domains. PMID:27184002

  10. Evaluation of SI engine exhaust gas emissions upstream and downstream of the catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C.M.; Costa, M.; Farias, T.L. [Mechanical Engineering Department, Instituto Superior Tecnico, Technical University of Lisbon, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal); Santos, H. [Escola Superior de Tecnologia e Gestao, Instituto Politecnico de Leiria, Leiria (Portugal)

    2006-11-15

    The conversion efficiency of a catalytic converter, mounted on a vehicle equipped with a 2.8l spark ignition engine, was evaluated under steady state operating conditions. The inlet and outlet chemical species concentration, temperature and air fuel ratio (A/F) were measured as a function of the brake mean effective pressure (BMEP) and engine speed (rpm). Oil temperature, coolant temperature, brake power and spark advance were also monitored. In parallel, a mathematical model for the catalytic converter has been developed. The main inputs of the model are the temperature, flow rate, chemical species mass flow and local A/F ratio as measured at the catalyst inlet section. The main conclusions are: (i) the exhaust gas and substrate wall temperatures at the catalyst outlet increase with BMEP and rpm; (ii) the HC conversion efficiency increases with the value of BMEP up to a maximum beyond which it decreases; (iii) the CO conversion efficiencies typically increase with BMEP; (iv) the NO{sub x} conversion efficiency remains nearly constant regardless of BMEP and rpm; (v) except for idle, the NO{sub x} conversion efficiency is typically the highest, followed in turn by the CO and HC conversion efficiencies; (vi) conversion efficiencies are lower for idle conditions, which can be a problem under traffic conditions where idle is a common situation; (vii) regardless of rpm and load, for the same flow rate the conversion efficiency is about the same; (viii) the model predictions slightly over estimate the exhaust gas temperature data at the catalyst outlet section with the observed differences decreasing with BMEP and engine speed; (ix) in general, the model predictions of the conversion efficiencies are satisfactory. (author)

  11. NUMERICAL SIMULATION OF EFFECTS OF WALL THICKNESS AND CELL DENSITY ON THE THREE-WAY CATALYTIC CONVERTER PERFORMANCE

    Institute of Scientific and Technical Information of China (English)

    Wu Guojiang; Tan Song; Huang Zhen

    2005-01-01

    The transient symmetric mathematical model is established, and the effects of the wall thickness and cell density on the performance of a three-way catalytic converter are studied using numerical modeling. The conclusions show that the light-off time and the pressure drop through a converter are decreased, and the conversion efficiency during the warm-up period keeps almost invariant with reduction of the wall thickness of substrates, and that the pressure drop through a converter and a conversion efficiency during the warm-up state increases, and the light-off time almost keeps invariant when increasing cell density of substrates. Therefore, future catalytic converters should develop in the direction of thin wall thickness and high cell density substrates simultaneously.

  12. Folding in solution of the C-catalytic protein fragment of angiotensin-converting enzyme.

    Science.gov (United States)

    Vamvakas, Sotirios-Spyridon M; Leondiadis, Leondios; Pairas, George; Manessi-Zoupa, Evy; Spyroulias, Georgios A; Cordopatis, Paul

    2009-08-01

    Angiotensin-converting enzyme (ACE) is a key molecule of the renin-angiotensin-aldosterone system which is responsible for the control of blood pressure. For over 30 years it has become the target for fighting off hypertension. Many inhibitors of the enzyme have been synthesized and used widely in medicine despite the lack of ACE structure. The last 5 years the crystal structure of ACE separate domains has been revealed, but in order to understand how the enzyme works it is necessary to study its structure in solution. We present here the cloning, overexpression in Escherichia coli, purification and structural study of the Ala(959) to Ser(1066) region (ACE_C) that corresponds to the C-catalytic domain of human somatic angiotensin-I-converting enzyme. ACE_C was purified under denatured conditions and the yield was 6 mg/l of culture. Circular dichroism (CD) spectroscopy indicated that 1,1,1-trifluoroethanol (TFE) is necessary for the correct folding of the protein fragment. The described procedure can be used for the production of an isotopically labelled ACE(959-1066) protein fragment in order to study its structure in solution by NMR spectroscopy.

  13. Pattern Formation and Chaotic Dynamics in a Cross-Flow Catalytic Converter with Kinetics of Detoxification of Exhaust Gases

    OpenAIRE

    Kohout, M.

    2012-01-01

    In this contribution, the range of patterns occurring due to interaction of transport and reactions characteristic of the three-way catalytic converter (TWC) have been explored. We examined whether and how spatiotemporal structures such as spatially nonhomogeneous steady states and travelling waves are produced. Furthermore we found that the system displays a wide variety of chaotic spatiotemporal patterns, which were examined in detail.

  14. Auto-thermal combustion of lean gaseous fuels utilizing a recuperative annular double-layer catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Budzianowski, W.M. [Wroclaw Univ. of Technology, Wroclaw (Poland). Div. of Chemical and Biochemical Processes, Faculty of Chemistry; Miller, R. [Wroclaw Univ. of Technology, Wroclaw (Poland). Inst. of Power Engineering and Fluid Mechanics, Faculty of Mechanical and Power Engineering

    2008-08-15

    This study investigated the auto-thermal combustion of lean gaseous fuels in a recuperative annular double-layer catalytic converter. An analysis of the stationary and transient performance of annular converters was presented. The feasibility of lean gaseous mixture combustion in auto-thermally operated recuperative annular double-layer catalytic converters was investigated. The aim of the study was to build a process model using mass, energy, and momentum differential balances. The model was used to study the static behaviour of a recuperative annular double layer converter; an annular converter operating in transient conditions; and energy accumulation and recuperation interactions. The effects of fuel temperature, external cooling, and fuel concentration were examined. Results of the study showed that a substantial reduction of the inter- and intra-phase resistances to mass and heat transfer was obtained. It was demonstrated that the use of a low value for the substrate's thermal conductivity accelerated ignition and retarded extinction. The recuperative converter was able to transfer short-time inlet disturbances of various parameters due to the energy accumulation and temporal reversed recuperation which counteracted destructive overheating of the catalysts. The stability analyses showed stable and unstable branches of solutions for the different parameters of the recuperative converter. 21 refs., 1 tab., 23 figs.

  15. Impact of Hong Kong's Voluntary Catalytic Converter Replacement Programme on Roadside Air Quality

    Science.gov (United States)

    Simpson, I. J.; Guo, H.; Louie, P. K. K.; Luk, C.; Lyu, X.; Meinardi, S.; Yam, Y. S.; Blake, D. R.

    2015-12-01

    As part of its ongoing policies to improve roadside air quality, in 2013 the Hong Kong government launched an incentive programme to replace catalytic converters and oxygen sensors in taxis and light buses mainly fueled by liquefied petroleum gas (LPG). The majority of replacements occurred from October 2013 to April 2014, with 75% of eligible vehicles participating in the programme, or 16,472 vehicles. Based on taxi exhaust measurements at a Hong Kong vehicle testing facility, the concentrations of n-butane, propane and i-butane (the primary components of LPG) decreased by 97% following the replacements. To determine the impact of the programme on roadside air quality, long-term measurements of volatile organic compounds (VOCs) were analyzed before, during and after the replacement programme, mainly at a busy roadside location in Mong Kok, Hong Kong. A clear decrease in the levels of major pollutants associated with LPG vehicle exhaust was observed at the roadside. For example, average (± 1 standard deviation) n-butane levels from October to April decreased from 13.0 ± 3.6 and 13.9 ± 2.6 ppbv in the two years preceding the programme, to 9.2 ± 2.9 ppbv during the programme, to 6.2 ± 1.7 ppbv the year after the programme. By contrast, compounds such as i-pentane that are not strongly associated with LPG or with LPG exhaust remained steady, averaging 0.90 ± 0.34, 1.01 ± 0.31, 0.93 ± 0.37, and 0.91 ± 0.42 ppbv from October to April of 2011/12, 2012/13, 2013/14 and 2014/15, respectively. Impacts of the programme on roadside levels of nitrogen oxides (NOx) and ozone (O3) will also be discussed. Because many taxis are high mileage vehicles that travel several hundred kilometers daily, their catalytic converters need to be replaced approximately every 18 months. Therefore ongoing vehicle maintenance will be required in order to preserve the gains made from this initial subsidy programme.

  16. Evaluation and development of measurement components for a catalytic converter test system

    Energy Technology Data Exchange (ETDEWEB)

    Chan, A.K.

    1997-08-01

    The purpose of this research and development project was to evaluate and configure the components of a test system designed for the analysis of full-scale vehicle-aged automobile catalytic converters. The components tested included an exhaust gas analyzer for measuring hydrocarbon, CO, CO{sub 2} and O{sub 2} contents and a chemiluminescence detector (CLD) for measuring NO{sub x}, as well as thermocouples and pressure meters. A software package (TestPoint vers.2.Ob, Capital Equipment) was used to develop a computer-based data sampling and acquisition interface with the components and sensors connected to the test system. Tests of the Sun MGA-1200, a non-dispersive infrared (NDIR) analyzer, with CO, CO{sub 2} and various hydrocarbons (propane and octane) revealed sensitivity to large pressure changes (greater than 500 mbar). There was no significant cross-sensitivity between the gases except for the slight response of the hydrocarbon (HC) register to water vapor and CO. However, the low range of HC(5-30 vppm) expected in car exhaust after the converter means any cross-sensitivity could have an effect on the measurement, depending on measurement conditions. Tests of the EcoPhysics CLD 700 NO{sub x} meter also indicated sensitivity to pressure. An executable TestPoint run-time application was created to allow near real-time monitoring of the test system using a desktop computer. Nine channels of analog data are fed to a desktop computer via an A/D board and seven exhaust gas parameters through an RS-232C interface with the MGA-1200 23 refs, 32 figs, 10 tabs. Examination paper

  17. The effect of oxygen storage capacity on the dynamic characteristics of an automotive catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United states). Dept. of Mechanical Engineering

    2007-07-01

    Automotive catalytic converters that reduce engine exhaust emissions are subject to transient conditions during a typical driving cycle. These conditions arise from changes in driving mode, the hysteresis and flow lags of the feedback control system, and result in fluctuations of air-fuel, exhaust gas flow rates and temperatures. The catalyst performance is also highly influenced by the oxygen storage capacity (OSC). This paper examined the influence of OSC on the catalyst dynamic behavior. The transient conditions were simulated by considering the catalyst subjected to temporal modulation in air-fuel ratio, exhaust gas composition and temperature. The paper presented the mathematical formulation including the development of governing equations. The governing equations were developed by considering the conservation of mass, energy and chemical species. It also presented the results and discussed the effect of sinusoidal modulation in the air-fuel ratio as well as the effect of sinusoidal modulation in exhaust composition. It was concluded that the presence of the OSC sensitivity influenced its response to the imposed modulation. The specific effect was dependent on the operating conditions and the type of the imposed modulations. 10 refs., 1 tab., 3 figs.

  18. A study of measurement and analysis of flow distribution in a close-coupled catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.S.; Kim, D.S. [Kookmin University, Seoul (Korea); Joo, Y.C. [Soonchunhyang University, Asan (Korea)

    2001-04-01

    In this study, results from an experimental and numerical study of flow distribution in a close-coupled catalytic converter (CCC) are presented. The experiments were carried out using a flow measurement system. Flow distribution at the exit of the first monolith in the CCC was measured using a pitot tube under steady and transient flow conditions. Numerical analysis was done using a CF D code at the same test conditions, and the results were compared with the experimental results. Experimental results showed that the uniformity index of exhaust gas velocity decreases as Reynolds number increases. Under the steady flow conditions, flow through each exhaust pipe concentrates on a small region of the monolith. Under the transient flow conditions, flow through each exhaust pipe with the engine firing order interacts with each other to spread the flow over the monolith face. The numerical analysis results support the experimental results, and help explain the flow pattern in the entry region of the CCC. (author). 6 refs., 8 figs.

  19. Evaluation of a catalyzed ceramic diesel particulate filter and catalytic converter on an underground mine vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, K.L.; Majewski, W.A. [Bureau of Mines, Minneapolis, MN (United States)]|[Diesel Controls, Ltd., Willowdale, Ontario (Canada)

    1995-12-31

    The U.S. Bureau of Mines (USBM) and Diesel Controls Limited evaluated a new diesel emission control system on an underground mine vehicle. The system was a catalyzed ceramic wall-flow diesel particulate filter (CDPF) combined with an catalytic converter, or diesel oxidation catalyst (DOC). This paper describes the design and installation of the system on a load-haul-dump (LHD). The results of screening tests conducted by the USBM are also given. The screening tests were conducted to determine if the device`s particulate collection efficiency, regeneration temperature, and effect on gaseous hydrocarbon (HC) and carbon monoxide (CO) emissions changed over the period it was being used. The system was removed from the LHD and evaluated in the laboratory after operating for 308 and 1200 hours. After 308 hours of operation, laboratory testing revealed its particulate collection efficiency varied from 41.0 to 93.5 percent, depending on engine operating conditions. Its regeneration temperature was about 415{degrees}C. It reduced HC emissions by up to 97.6 percent, and CO by up to 95.0 percent. When tested in the laboratory after operating for 1200 hours on the vehicle, no significant change in performance was observed.

  20. Emission reduction from a diesel engine fueled by pine oil biofuel using SCR and catalytic converter

    Science.gov (United States)

    Vallinayagam, R.; Vedharaj, S.; Yang, W. M.; Saravanan, C. G.; Lee, P. S.; Chua, K. J. E.; Chou, S. K.

    2013-12-01

    In this work, we propose pine oil biofuel, a renewable fuel obtained from the resins of pine tree, as a potential substitute fuel for a diesel engine. Pine oil is endowed with enhanced physical and thermal properties such as lower viscosity and boiling point, which enhances the atomization and fuel/air mixing process. However, the lower cetane number of the pine oil hinders its direct use in diesel engine and hence, it is blended in suitable proportions with diesel so that the ignition assistance could be provided by higher cetane diesel. Since lower cetane fuels are prone to more NOX formation, SCR (selective catalyst reduction), using urea as reducing agent, along with a CC (catalytic converter) has been implemented in the exhaust pipe. From the experimental study, the BTE (brake thermal efficiency) was observed to be increased as the composition of pine oil increases in the blend, with B50 (50% pine oil and 50% diesel) showing 7.5% increase over diesel at full load condition. The major emissions such as smoke, CO, HC and NOX were reduced by 70.1%, 67.5%, 58.6% and 15.2%, respectively, than diesel. Further, the average emissions of B50 with SCR and CC assembly were observed to be reduced, signifying the positive impact of pine oil biofuel on atmospheric environment. In the combustion characteristics front, peak heat release rate and maximum in-cylinder pressure were observed to be higher with longer ignition delay.

  1. Dissolution of Ceramic Monolith of Spent Catalytic Converters by Using Hydrometallurgical Methods / Rozpuszczanie Monolitu Ceramicznego Zużytych Katalizatorów Na Drodze Hydrometalurgicznej

    Directory of Open Access Journals (Sweden)

    Willner J.

    2015-12-01

    Full Text Available Catalytic converters contain the catalytic substance in their structure, which is a mixture of Platinum Group Metals (PGMs: platinum, palladium and rhodium. The prices of these metals and a growing demand for them in the market, make it necessary to recycle spent catalytic converters and recovery of PGMs. The ceramic monolith of catalytic converters is still a predominant material in its construction among of multitude of catalytic converters which are in circulation. In this work attempts were made to leach additional metals (excluding Pt from comminuted ceramic monolith. Classic leachant oxidizing media 10M H2SO4, HCl and H3PO4 were used considering the possibility of dissolution of the ceramic monolith.

  2. Effect of the Sequence of the Thermoelectric Generator and the Three-Way Catalytic Converter on Exhaust Gas Conversion Efficiency

    Science.gov (United States)

    Su, Chuqi; Tong, Naiqiang; Xu, Yuman; Chen, Shan; Liu, Xun

    2013-07-01

    The potential for thermoelectric exhaust heat recovery in vehicles has increased with recent improvements in the efficiency of thermoelectric generators (TEGs). The problem with using thermoelectric generators for vehicle applications is whether the device is compatible with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. Based on ANSYS CFX simulation analysis of the impact of two positional relationships between the TEG and three-way catalytic converter in the exhaust system on the working efficiency of both elements, it is concluded that the layout with the front three-way catalytic converter has an advantage over the other layout mode under current conditions. New ideas for an improvement program are proposed to provide the basis for further research.

  3. Oxidative destruction of biomolecules by gasoline engine exhaust products and detoxifying effects of the three-way catalytic converter.

    Science.gov (United States)

    Blaurock, B; Hippeli, S; Metz, N; Elstner, E F

    1992-01-01

    Aqueous solutions of engine exhaust condensation products were derived from cars powered by diesel or four-stroke gasoline engines (with and without three-way catalytic converter). The cars were operated on a static test platform. Samples of the different exhaust solutions accumulated in a Grimmer-type distillation trap (VDI 3872) during standard test programs (Federal Test Procedure) were incubated with important biomolecules. As indicators of reactive oxygen species or oxidative destruction, ascorbic acid, cysteine, glutathione, serum albumin, the enzymes glycerinaldehyde phosphate dehydrogenase and xanthine oxidase, and the oxygen free-radical indicator keto-methylthiobutyrate were used. During and after the incubations, oxygen activation (consumption) and oxidative destruction were determined. Comparison of the oxidative activities of the different types of exhaust condensates clearly showed that the exhaust condensate derived from the four-stroke car equipped with a three-way catalytic converter exhibited by far the lowest oxidative and destructive power. PMID:1283938

  4. Ignition harness for safeguarding of catalytic converter function and EMC. Zuendgeschirr zur Sicherung der Katalysatorfunktion und der EMV

    Energy Technology Data Exchange (ETDEWEB)

    Bergold, M.

    1994-10-01

    In modern electronically controlled petrol engines ignition reliability and the reduction of the electromagnetic interference caused by ignition are becoming more and more important. These requirements must be met by modern ignition cables with suppressor connectors, expecially with regard to protection of the catalytic converter and fault-free functioning of vehicle electronics, some of which are essential safety features, over the entire service life of the vehicle. Bosch develops and manufactures ignition harnesses with suppression at its Waiblingen location. (orig.)

  5. Experimental Investigation on Combined Effect of EGR and Three-way Catalytic Converter for IDI Diesel Engine.

    OpenAIRE

    P Suresh Kumar; Ramesh Kumar Donga; Sahoo, P. K.

    2013-01-01

    In the past few decades, an alternate source of energy has been the growing concern with respect to environment and energy reserves utilization. Also the enhancement of industrialization and motorization at global level has strengthened further towards the alternate energy sources like bio fuels etc. The objective of the research work was to effectively reduce the nitrogen oxides (NOX) emissions with the combination of exhaust gas recirculation (EGR) and three-way catalytic converter fuelled ...

  6. Experimental Investigation on Combined Effect of EGR and Three-way Catalytic Converter for IDI Diesel Engine.

    Directory of Open Access Journals (Sweden)

    P. Suresh Kumar

    2013-12-01

    Full Text Available In the past few decades, an alternate source of energy has been the growing concern with respect to environment and energy reserves utilization. Also the enhancement of industrialization and motorization at global level has strengthened further towards the alternate energy sources like bio fuels etc. The objective of the research work was to effectively reduce the nitrogen oxides (NOX emissions with the combination of exhaust gas recirculation (EGR and three-way catalytic converter fuelled with diesel, jatropha biodiesel (JBD and their blends at full load of indirect injection (IDI diesel engines. The engine was tested by diesel, 100% biodiesel (JB 100, blends of 80% diesel and 20% biodiesel (JB 20 and other blends like JB 40, JB 60 and JB 80. The engine characteristics with jatropha biodiesel were compared against those obtained using diesel fuel. From results it is observed that nitrogen oxide emissions of JBD are more than that diesel fuel. These high NOX emissions are due to the presence of unsaturated fatty acids and the advanced injection caused by the higher bulk modulus of JBD and their blends. A four stroke single cylinder water cooled IDI diesel engine was used for investigation. Nitrogen oxides, carbon monoxide, carbon dioxide and smoke were recorded and various engine performance parameters were also evaluated. The results and discussion based on the effect of emission controlling systems on engine performance and emission characteristics of JB 100, JB 80, JB 60, JB 40, JB 20 and diesel fuel without emission controlling systems. The performance parameters and nitrogen oxide emissions are measured and recorded for diesel fuel, JBD and their blends. The results showed that at 5% EGR + three way catalytic converter for JB 100, at 40% EGR + three way catalytic converter for JB 80, JB60 and JB 40. And at 35% EGR + three way catalytic converter for JB 20 and diesel fuels, the N0x emissions effectively reduced compared to without emission

  7. DESIGN NOTE: A compact catalytic converter for the production of para-hydrogen

    Science.gov (United States)

    Juarez, A. M.; Cubric, D.; King, G. C.

    2002-05-01

    The design and operation of a compact converter to produce a constant flow of para-hydrogen from normal hydrogen is described. The converter features a paramagnetic compound (nickel sulfate) that catalyses the conversion of ortho- to para-hydrogen at temperatures of 14-21 K. The converter has been tested by measuring rotationally resolved photoelectron spectra in the para-hydrogen produced. The percentage of the para-hydrogen species in the converted gas was determined to be >97%.

  8. Low-emission diesel engine with catalytic converter. Schadstoffarmer Dieselmotor mit Katalysator; Verminderung der Schadstoffemissionen bei Nutzfahrzeugdieselmotoren durch motorische Massnahmen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Held, W.

    1994-01-01

    The report describes investigations for the purpose of reducing pollutant emissions in diesel engines. Subjects: State of the art; Experimental procedure; Fuel injection systems; Optimisation, mixing and combustion; Measures not involving engine reconstruction; Oxidative catalytic converters. (HW)

  9. Research on Integration of an Automotive Exhaust-Based Thermoelectric Generator and a Three-Way Catalytic Converter

    Science.gov (United States)

    Deng, Y. D.; Chen, Y. L.; Chen, S.; Xianyu, W. D.; Su, C. Q.

    2015-06-01

    A key research topic related to thermoelectric generators (TEGs) for automotive applications is to improve their compatibility with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. A new TEG integrated with a three-way catalytic converter (CTEG) by reshaping the converter as the heat exchanger is proposed. A heat-flux coupling simulation model of the integrated TEG is established at the light-off stage of the original three-way catalytic converter (TWC). Temperature distribution maps of the integrated heat exchanger, thermoelectric modules, and cooling-water tank are obtained to present the process of energy flow among the parts of the CTEG. Based on the simulation results, the output power of the CTEG is calculated by a mathematical model. A minimum output power of 31.93 W can be obtained by conversion when the TWC starts working at steady conditions. Theoretically, this case study demonstrates the great potential for use of CTEGs in vehicles.

  10. A non-stationary model for catalytic converters with cylindrical geometry

    OpenAIRE

    Hoernel, J. -D.

    2006-01-01

    We prove some existence and uniqueness results and some qualitative properties for the solution of a system modelling the catalytic conversion in a cylinder. This model couples parabolic partial differential equations posed in a cylindrical domain and on its boundary.

  11. Platinum levels in natural and urban soils from Rome and Latium (Italy): significance for pollution by automobile catalytic converter.

    Science.gov (United States)

    Cinti, D; Angelone, M; Masi, U; Cremisini, C

    2002-07-01

    Platinum concentrations in topsoil samples collected in 1992 (48) and in 2001 (16) from the urban area of Rome have been determined by ICP-MS. Concentrations in 47 soil samples collected in 1992 from natural sites of Latium (an area around Rome) have been determined for a first assessment of natural background levels. The Pt concentrations in Rome urban soils collected in 1992 range from 0.8 to 6.3 ng/g (mean = 3.8 +/- 1.0) overlapping the concentration range of natural soils from Latium (mean = 3.1 +/- 2.1 ng/g). No significant correlation has generally been found between Pt contents in the 'natural' soils and related bedrock or major pedogenetic parameters. These results suggest that there is no evidence of Pt pollution in Rome urban soils at that time, because the massive use of the automobile catalytic converter has only just started. Higher (up to six times more) Pt concentrations, than those measured in the 1992 samples, have been measured, in some cases, in Rome urban soils collected in 2001, suggesting a possible start of Pt accumulation because of the large-scale use in the last decade of automobile catalytic converters. At the same time, a clear decrease of lead levels in Rome urban soils with respect to the levels measured in 1992 has been observed, paralleling the decreasing number of lead gasoline-fuelled cars. Here we present one of the first systematic studies for defining background levels of Pt in Italian natural soils, thus allowing for monitoring, in the future, should any possible Pt pollution caused by the use of automobile catalytic converter, especially in urban soils, occur. PMID:12109480

  12. Platinum levels in natural and urban soils from Rome and Latium (Italy). Significance for pollution by automobile catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Cinti, D.; Masi, U. [Dipartimento di Scienze della Terra, Universita ' La Sapienza' , 00185 Rome (Italy); Angelone, M.; Cremisini, C. [ENEA, TEIN CHIM, C.R.Casaccia, V. Anguillarese 301, 00060 S. M. Di Galeria, Rome (Italy)

    2002-07-03

    Platinum concentrations in topsoil samples collected in 1992 (48) and in 2001 (16) from the urban area of Rome have been determined by ICP-MS. Concentrations in 47 soil samples collected in 1992 from natural sites of Latium (an area around Rome) have been determined for a first assessment of natural background levels. The Pt concentrations in Rome urban soils collected in 1992 range from 0.8 to 6.3 ng/g (X=3.8{+-}1.0) overlapping the concentration range of natural soils from Latium (X=3.1{+-}2.1 ng/g). No significant correlation has generally been found between Pt contents in the 'natural' soils and related bedrock or major pedogenetic parameters. These results suggest that there is no evidence of Pt pollution in Rome urban soils at that time, because the massive use of the automobile catalytic converter has only just started. Higher (up to six times more) Pt concentrations, than those measured in the 1992 samples, have been measured, in some cases, in Rome urban soils collected in 2001, suggesting a possible start of Pt accumulation because of the large-scale use in the last decade of automobile catalytic converters. At the same time, a clear decrease of lead levels in Rome urban soils with respect to the levels measured in 1992 has been observed, paralleling the decreasing number of lead gasoline-fuelled cars. Here we present one of the first systematic studies for defining background levels of Pt in Italian natural soils, thus allowing for monitoring, in the future, should any possible Pt pollution caused by the use of automobile catalytic converter, especially in urban soils, occur.

  13. Review of study on automotive catalytic converter%汽车催化转化器研究概述

    Institute of Scientific and Technical Information of China (English)

    王亚军; 冯长根; 王丽琼; 郭新亚

    2001-01-01

    综述了近30 年来国内外在汽车催化转化器方面的研究概况,包括化学反应动力学、传热传质、气体流动、催化器暂态行为、失效、模型、设计、快速起燃和低排放技术等。%The studies on automotive catalytic converter,including reaction kinetics,heat and mass transfer,gas distribution,transient behavior,deactivation,modeling,design,fast light-off and low emission techniques,were reviewed.

  14. Automobile air pollution: control equipment--catalytic converters. Volume 2. 1977-January, 1980 (citations from the Engineering Index Data Base). Report for 1977-Jan 80

    Energy Technology Data Exchange (ETDEWEB)

    Cavagnaro, D.M.

    1980-02-01

    The citations of worldwide engineering literature cover automotive catalytic converters. Included are such topics as converter design and materials, performance tests, effectiveness in pollutant reduction, catalyst poisoning, catalyst selection, chemistry involved in the emission control, and the overall feasibility of using these converters under normal driving conditions. Control of sulfuric acid and sulfate emissions is also discussed. (This updated bibliography contains 142 abstracts, 37 of which are new entries to the previous edition.)

  15. The catalytic converter - The all-purpose remedy for tractors?; Der Katalysator, ein Allheilmittel fuer den Traktor? Wirkung und Langzeitverhalten eines Abgaskatalysators an einem Obstbautraktor mit Dieselmotor

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, E. [Eigenoessische Forschungsanstalt fuer Agrarwirtschaft und Landtechnik (FAT), Taenikon (Switzerland)

    2001-07-01

    This illustrated report by the Swiss Federal Research Institute for Agricultural Economics and Engineering examines the effect and long-term behaviour of an exhaust catalytic-converter system for a tractor used in orchards. The problems posed by the emissions from diesel engines in 'off-road' use like oxides of nitrogen, carbon monoxide, sulphur dioxide, soot particles and obnoxious odours are discussed and attempts to solve these problems using catalytic converters are described. The report discusses the special health problems for personnel caused by diesel emissions in poorly ventilated workplaces such as orchards, vineyards and greenhouses. Details on a converter that was fitted experimentally to a tractor used in an orchard are given and results of measurements made on emissions, motor power and fuel consumption are presented and discussed in detail. The report is concluded with a summary of the main findings and recommends the installation of add-on catalytic converters for tractors used in poorly ventilated areas.

  16. THREE-WAY-CATALYTIC CONVERTERS: ANALYTICAL INVESTIGATION OF A TWO-PHASE MODELL I. SEPARATION METHOD

    OpenAIRE

    Volkmann, J.; Migranov, N.

    2010-01-01

    The two-phase-model describes the thermal and chemical behaviour of a three-way-catalytic onverter (TWC). According to this model energy, mass balance equations for gas and solid phase are taking into account. These equations are investigated by the separation of variables method in order to construct solutions.

  17. Evaluation of four sample treatments for determination of platinum in automotive catalytic converters by graphite furnace atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Conventional and microwave assisted digestion, both using aqua regia, alkaline fusion with lithium metaborate and aqueous slurries were evaluated as sample treatments for determination of Pt in automotive catalytic converters by Graphite Furnace Atomic Absorption Spectrometry (GF-AAS). Determination of platinum by GF-AAS in samples of the catalytic converter's substrates, prepared by the four methods described, indicates that the highest platinum concentration i.e. maximum Pt extraction in the range of 748 ± 15-998 ± 10 μg mL-1, is obtained for samples dissolved by alkaline fusion, closely followed by analysis of aqueous plus Triton X-100 slurries 708 ± 14-958 ± 10 μg mL-1, while neither one of the acid digestion procedures achieved total dissolution of the samples. Slurry analysis is thus shown to be a viable alternative and is recommended, based on its speed and ease of implementation. Aqueous standards calibration curves and the standard addition methods were also compared. The results showed that no appreciable matrix effects are present, regardless of the sample preparation procedure used. Precision of the measurements, expressed as percentage relative standard deviation, ranged between 2.5 to 4.9%. Accuracy of the results was assessed by recovery tests which rendered values between 98.9 and 100.9%

  18. CFD simulation of the effect of upstream flow distribution on the light-off performance of a catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Wu Guojiang [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)]. E-mail: wugj@citiz.net; Song Tan [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2005-08-15

    This paper describes the evolutions of the distributions of temperature and concentration in the monolith during the cold-start period and the effects of the flow distributions in the monolith on the performance of a catalytic converter using numerical simulation. The effects of the flow distributions on the light-off, warm-up performance and the temporal variation of the solid temperature were studied through numerical simulation. The following conclusions were obtained from the predicted light-off curves and the steady conversion efficiency: (1) The light-off time increases and the total outlet conversion efficiency reduces as the flow uniformity index decreases, which is in good agreement with experimental results. (2) The conversion efficiency decreases due to the reduction of residence time caused by the increase of the velocity as the radius is reduced. The analyses on the distribution of temperature in the monolith show that the temperatures of the solid in the area near the front face of the substrate rise as the radius increases, and the radial gradient of the temperature of the solid becomes greater as the flow uniformity index decreases. An experiment on the flow distribution in a catalytic converter with a honeycomb spherical arc was conducted. Experimental results show that the flow distribution in the monolith can be improved greatly by installing the honeycomb spherical arc in the tapered inlet header with a penalty of a relatively small increase of pressure drop.

  19. Evaluation of four sample treatments for determination of platinum in automotive catalytic converters by graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Puig, Ana I.; Alvarado, José I.

    2006-09-01

    Conventional and microwave assisted digestion, both using aqua regia, alkaline fusion with lithium metaborate and aqueous slurries were evaluated as sample treatments for determination of Pt in automotive catalytic converters by Graphite Furnace Atomic Absorption Spectrometry (GF-AAS). Determination of platinum by GF-AAS in samples of the catalytic converter's substrates, prepared by the four methods described, indicates that the highest platinum concentration i.e. maximum Pt extraction in the range of 748 ± 15-998 ± 10 μg mL - 1 , is obtained for samples dissolved by alkaline fusion, closely followed by analysis of aqueous plus Triton X-100 slurries 708 ± 14-958 ± 10 μg mL - 1 , while neither one of the acid digestion procedures achieved total dissolution of the samples. Slurry analysis is thus shown to be a viable alternative and is recommended, based on its speed and ease of implementation. Aqueous standards calibration curves and the standard addition methods were also compared. The results showed that no appreciable matrix effects are present, regardless of the sample preparation procedure used. Precision of the measurements, expressed as percentage relative standard deviation, ranged between 2.5 to 4.9%. Accuracy of the results was assessed by recovery tests which rendered values between 98.9 and 100.9%.

  20. 车用催化转化器的压力损失%Pressure losses in automotive catalytic converters

    Institute of Scientific and Technical Information of China (English)

    帅石金; 王建昕; 庄人隽

    2001-01-01

    Catalytic converters in the exhaust system increase the engine'sexhaust back pressure, thus penalizing the vehicle's fuel economy and power output. The sensitivity of the main factors affecting the pressure losses in automotive catalytic converters was investigated based on a theoretical analysis of the logarithm derivative. A computational fluid dynamics (CFD) code was used to simulate the flow in the catalytic converters to study the effects of structures and configurations of the diffusion and contraction headers on the pressure losses. Theoretical results show that the converter pressure losses mainly result from the monolith resistance and diffusion header losses. Of the physical monolith parameters, the channel diameter has the largest impact on the monolith resistance. The inlet cone angle, inlet diffusion header configuration and outlet cone angle also contribute to the pressure losses.%在汽车排气系统上安装催化转化器会造成较大的排气背压,对发动机的动力性和经济性带来负面影响。在分析催化转化器压力损失来源的基础上,采用对数求导方法对影响压力损失的主要因素进行了敏感性研究,并用计算流体力学(CFD)软件研究了催化转化器扩张管和收缩管的形状结构对其压力损失的影响。研究表明:载体的沿程阻力和扩张管的局部阻力是构成催化转化器压力损失的主要来源;载体的直径对载体的沿程阻力影响最大;入口扩张角、扩张管形状及收缩角对催化转化器的压力损失有较大影响。

  1. Study of divided converter catalytic system satisfying quick warm up and high heat resistance

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Toshihiro; Hirayama, Hiroshi; Itoh, Takaaki; Yaegashi, Takehisa [Toyota Motor Corp., Aichi (Japan)

    1996-09-01

    Catalyst specifications and converter layouts were studied to identify the high conversion performance under various in-use driving conditions, high mileage intervals and extended life cycle. The effects of volumes, configuration, selection and loading distribution of precious metals, additive components and substrate type for catalyst were studied on engine dynamometers and vehicle tests to optimize a catalyst converter system. Moreover, model gas experiments were conducted to analyze deterioration mechanisms and conversion characteristics of catalysts. As a result, the concept of a divided catalyst converter system, which provides separate functions for a close-coupled and an under-floor catalyst, was found to be effective for the future exhaust system. For reducing HC emissions, the close-coupled catalyst should warm up quickly and resist a high temperature. The under-floor catalyst, located at a rather low temperature position, is durable and maintains high NOx conversion.

  2. Characterization and application of an externally mounted catalytic converter for aircraft measurements of NOy

    Science.gov (United States)

    Lange, L.; Fischer, H.; Parchatka, U.; Gurk, C.; Zenker, T.; Harris, G. W.

    2002-08-01

    A novel design for an airborne NOy converter was implemented, characterized in the laboratory, and used extensively for in situ tropospheric and stratospheric measurements of total reactive nitrogen (NOy). During field deployments, the converter is mounted outside the aircraft fuselage, avoiding the need for an inlet line. In flight, the converter can be calibrated by the addition of standard gases close to the sample inlet, compensating for any changes in the instrument sensitivity caused by changing operating conditions. The system has been used successfully during several Stratosphere Troposphere Experiments by Aircraft Measurements campaigns in the lowermost stratosphere and upper troposphere for the measurement of total reactive nitrogen. The detection limit of the system is approximately 100 pptv for 10 s integrated data (2σ). The precision, deduced from the reproducibility of the in-flight calibrations, is 7% and the accuracy is about 30%. Laboratory studies demonstrate that interference from HCN, NH3, and CH3CN is negligible for background conditions.

  3. Targeted Catalytic Inactivation of Angiotensin Converting Enzyme by Lisinopril-Coupled Transition Metal Chelates

    OpenAIRE

    Joyner, Jeff C.; Hocharoen, Lalintip; Cowan, J. A.

    2012-01-01

    A series of compounds that target reactive transition metal chelates to somatic Angiotensin Converting Enzyme (sACE-1) have been synthesized. Half maximal inhibitory concentrations (IC50) and rate constants for both inactivation and cleavage of full length sACE-1 have been determined and evaluated in terms of metal-chelate size, charge, reduction potential, coordination unsaturation, and coreactant selectivity. Ethylenediamine-tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), 1,4,7,10-tet...

  4. Modelling of an SCR catalytic converter for diesel exhaust after treatment: Dynamic effects at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tronconi, Enrico; Nova, Isabella; Ciardelli, Cristian [Dipartimento di Chimica, Materiali e Ingegneria Chimica ' G. Natta' , Politecnico di Milano, P.zza L. Da Vinci 32, 20133 Milano (Italy); Chatterjee, Daniel; Bandl-Konrad, Brigitte; Burkhardt, Thomas [DaimlerChrysler AG Abteilung RBP/C, HPC: 096-E220, D-70546 Stuttgart (Germany)

    2005-08-15

    As part of a fundamental and applied work on the development of an unsteady mathematical model of the NH{sub 3}-selective catalytic reduction (SCR) process for design and control of integrated after-treatment systems of heavy-duty engines, we present herein a transient kinetic analysis of the standard SCR NO+NH{sub 3} system which provides new insight in the catalytic kinetics and mechanism prevailing at low temperatures. Based on kinetic runs performed over a commercial powdered V{sub 2}O{sub 5}-WO{sub 3}-TiO{sub 2} catalyst in the 175-450{sup o}C T-range feeding NH{sub 3} and NO (1000ppm) in the presence of H{sub 2}O (1-10%, v/v) and O{sub 2} (2-6%, v/v), an original dual-site modified redox rate law is derived which effectively accounts for NH{sub 3} inhibition effects observed during transient reactive experiments at T<250{sup o}C. We also demonstrate that implementation of the novel modified redox kinetics into a fully predictive 1D+1D model of SCR monolith reactors can significantly improve simulations of SCR transient runs at different scales, including engine test bench experiments over full-scale SCR honeycomb catalysts.

  5. Traffic and catalytic converter - related atmospheric contamination in the metropolitan region of the city of Rio de Janeiro, Brazil.

    Science.gov (United States)

    da Silva, Lílian Irene Dias; de Souza Sarkis, Jorge Eduardo; Zotin, Fátima Maria Zanon; Carneiro, Manuel Castro; Neto, Arnaldo Alcover; da Silva, Alzira dos Santos Amaral Gomes; Cardoso, Mauri José Baldini; Monteiro, Maria Inês Couto

    2008-03-01

    In this work, 24-h PM10 samples were collected in Rio de Janeiro, Brazil, and analysed for trace elements (Cd, Ce, Cu, La, Mo, Ni, Pb, Pd, Rh, Sb and Sn). The sampling was carried out at five locations (Bonsucesso; Centro, downtown city; Copacabana; Nova Iguaçu and Sumaré) with different traffic densities and anthropogenic activities. An analytical method based on the EPA method for the determination of trace elements in airborne particulate matter (PM), using ultrasonic-assisted extraction and inductively coupled plasma mass spectrometry (ICP-MS) was applied. Our results suggest that vehicular traffic is the most important source of environmental pollution at the studied sites. The presence of Mo, Pd and Rh in the analysed filters reflects an additional source of pollution caused by the erosion and deterioration of automotive catalytic converters. PMID:18082244

  6. Synthetic Peptides as Structural Maquettes of Angiotensin-I Converting Enzyme Catalytic Sites

    Directory of Open Access Journals (Sweden)

    Zinovia Spyranti

    2010-01-01

    Full Text Available The rational design of synthetic peptides is proposed as an efficient strategy for the structural investigation of crucial protein domains difficult to be produced. Only after half a century since the function of ACE was first reported, was its crystal structure solved. The main obstacle to be overcome for the determination of the high resolution structure was the crystallization of the highly hydrophobic transmembrane domain. Following our previous work, synthetic peptides and Zinc(II metal ions are used to build structural maquettes of the two Zn-catalytic active sites of the ACE somatic isoform. Structural investigations of the synthetic peptides, representing the two different somatic isoform active sites, through circular dichroism and NMR experiments are reported.

  7. New data on the mobility of Pt emitted from catalytic converters.

    Science.gov (United States)

    Fliegel, Daniel; Berner, Zsolt; Eckhardt, Detlef; Stüben, Doris

    2004-05-01

    The mobility and speciation of Pt was investigated in dust deposited in highway tunnels and in gully sediments. For this, a sequential extraction technique was used in combination with a microwave digestion procedure, followed by detection of Pt with high resolution ICP-MS. A digestion procedure using HNO(3)/HCl/H(2)O(2) was developed and its efficiency tested for environmental materials. Total Pt contents ranged from approximately 100 to 300 microg/kg. The high share of chemically mobile Pt in the tunnel dust (up to about 40%) indicates that Pt is predominantly emitted in a mobile form from the converter. The absence of a mobile fraction in the gully sediment is explained by the elution of Pt by run-off. Except for the mobile and easily mobilised fractions none of the other fractions of the sequential extraction contains Pt, neither in the dust samples nor in the gully sediment.

  8. Control Oriented Modelling of Three-way Catalytic Converter%面向控制的三效催化转化器建模

    Institute of Scientific and Technical Information of China (English)

    何玲; 于秀敏; 许楠; 于洪洋

    2011-01-01

    为了利用Pt/Rh/CeO2/γAl2O3三效催化转化器的动态特性降低排放,开发了面向控制的三效催化转化器模型,将求解的Ce表面相对O2覆盖率(ROC)作为推理传感器,为控制器提供反馈信号准备.结果表明,面向控制的三效催化转化器模型精度满足要求,模型求解的氧存储能力(OSC)可用于OBD在线诊断三效催化转化器是否老化,并可准确求解三效催化转化器出口过量空气系数和Ce表面相对O2覆盖率.%A control oriented model of three-way catalytic converter was developed to reduce emission by using the dynamic characteristics of Pt/Ph/CeO2/γ-Al2O3 three-way catalytic converter. The calculated relative oxygen coverage of Ce surface was taken as the deduction sensor to provide feedback signal preparation for controller. The results show that precision of the control oriented model of three-way catalytic converter can meet the requirements and the calculated oxygen storage capacity (OSC) can be used to determine the aging state of the three-way catalytic converter through OBD online diagnosis. Moreover,the excess air ratio of the three-way catalytic converter outlet and relative oxygen coverage of Ce surface can be calculated correctly.

  9. Implications of platinum-group element accumulation along U.S. roads from catalytic-converter attrition.

    Science.gov (United States)

    Ely, J C; Neal, C R; Kulpa, C F; Schneegurt, M A; Seidler, J A; Jain, J C

    2001-10-01

    Automobile catalytic converters are dispersing platinum-group elements (PGEs) Rh, Pt, and Pd into the environment (1-3). This paper represents the first detailed study to assess the PGE content of soils and grasses from U.S. roadsides. These soils were analyzed using cation exchange pretreatment and ultrasonic nebulizer-ICP-MS (4). Highway and several urban sites showed Pt abundances of 64-73 ng/g immediately adjacent to the roadside, with corresponding Pd and Rh abundances of 18-31 ng/g and 3-7 ng/g, respectively. All Pt and most Pd and Rh abundances are statistically above local background soil values. Platinum, Rd, and Rh show positive correlations with traffic-related elements (Ni, Cu, Zn, and Pb) but no correlations with nontraffic-related elements (Y, Ga). Iridium and Ru show no correlations with any of these trace elements. These PGE abundances are comparable to European studies (5-7) and are approaching concentrations that would be economically viable to recover. This study also demonstrates transport of Pt statistically above background more than 50 m from the roadside. Further study is necessary to see how mobile the PGEs are in roadside environments, but these initial data indicate only Pt is taken up by plants. PMID:11642438

  10. LDV measurement, flow visualization and numerical analysis of flow distribution in a close-coupled catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Duk Sang; Cho, Yong Seok [Kookmin Univ., Seoul (Korea, Republic of)

    2004-11-01

    Results from an experimental study of flow distribution in a Close-coupled Catalytic Converter (CCC) are presented. The experiments were carried out with a flow measurement system specially designed for this study under steady and transient flow conditions. A pitot tube was a tool for measuring flow distribution at the exit of the first monolith. The flow distribution of the CCC was also measured by LDV system and flow visualization. Results from numerical analysis are also presented. Experimental results showed that the flow uniformity index decreases as flow Reynolds number increases. In steady flow conditions, the flow through each exhaust pipe made some flow concentrations on a specific region of the CCC inlet. The transient test results showed that the flow through each exhaust pipe in the engine firing order, interacted with each other to ensure that the flow distribution was uniform. The results of numerical analysis were qualitatively accepted with experimental results. They supported and helped explain the flow in the entry region of CCC.

  11. The effects of the catalytic converter and fuel sulfur level on motor vehicle particulate matter emissions: gasoline vehicles.

    Science.gov (United States)

    Maricq, M Matti; Chase, Richard E; Xu, Ning; Podsiadlik, Diane H

    2002-01-15

    Scanning mobility and electrical low-pressure impactor particle size measurements conducted during chassis dynamometer testing reveal that neither the catalytic converter nor the fuel sulfur content has a significant effect on gasoline vehicle tailpipe particulate matter (PM) emissions. For current technology, port fuel injection, gasoline engines, particle number emissions are < or = 2 times higher from vehicles equipped with blank monoliths as compared to active catalysts, insignificant in contrast to the 90+% removal of hydrocarbons. PM mass emission rates derived from the size distributions are equal within the experimental uncertainty of 50-100%. Gravimetric measurements exhibit a 3-10-fold PM mass increase when the active catalyst is omitted, which is attributed to gaseous hydrocarbons adsorbing onto the filter medium. Both particle number and gravimetric measurements show that gasoline vehicle tailpipe PM emissions are independent (within 2 mg/mi) of fuel sulfur content over the 30-990 ppm concentration range. Nuclei mode sulfate aerosol is not observed in either test cell measurements or during wind tunnel testing. For three-way catalyst equipped vehicles, the principal sulfur emission is SO2; however a sulfur balance is not obtained over the drive cycle. Instead, sulfur is stored on the catalyst during moderate driving and then partially removed during high speed/load operation. PMID:11827063

  12. Bio-Diesel production and Effect of Catalytic Converter on Emission performance with Bio-Diesel Blends

    Directory of Open Access Journals (Sweden)

    R.Murali Manohar

    2010-06-01

    Full Text Available Bio-Diesel the word itself defines almost all the features of the Bio-Diesel literary. In the Era of this Global Warming where the people are making their living more and more comfortable and they are deteriorating the environment also. The uses of the automobiles with the conventional source of fuel leads to the production of the toxic gaseous substances like carbon monoxide, carbon dioxide, oxides of nitrogen, oxide of sulphur, hydro-carbons etc. The limitation comes with the rise in the price of the fuel as well as the produce of the green house gases as the exhaust gas. In the present study, a new method has been employed to produce Bio-Diesel in a homely basis. Theproduction of the Bio-Diesel is done by using Bio-Diesel processor. It requires the used vegetable oil, methanol and the lye with the accurate proportionate. Generally, emissions of regulated compounds changed linearly with the blend level. The objective is to detect any posit ive or negative effects depending on blend levels, because conventional diesel fuel and biodiesel can be blended in every ratio. The known positive and negative effects of biodiesel varied accordingly and investigate the effect of Catalytic Converter on emission performance with Bio- Diesel Blends.

  13. FE-analysis of a catalytic converter during canning process and in operating state of the vehicle; FE-Analyse eines Katalysators beim Fertigungsprozess und im Fahrzeugbetrieb

    Energy Technology Data Exchange (ETDEWEB)

    Wenz, M.; Lakshminarayanan, Saravanan; Wirth, G.; Dong Ming [J. Eberspaecher GmbH und Co. KG, Esslingen (Germany)

    2006-01-01

    Since the introduction of three-way catalytic converter in exhaust system of spark-ignition engines in Europe had started during the year of the 1980s, the mechanical and thermal loads on this system has been considerably increased. The oscillation accelerations and temperatures of this part have increased because of shifting it from the under body construction unit to the manifold. The present article from Eberspaecher describers the FEM analysis of loads and safety factors of the mat materials in a catalytic converter during the canning process and in the operating state of the vehicle. The mounting of the ceramic substrate in the tin can takes place, like increasingly applied today, by usage of an aluminum oxide fiber mat. (orig.)

  14. Heat transfer and chemical kinetics in the exhaust system of a cold-start engine fitted with a three-way catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S.H.; Hoang, D.L. [Nanyang Technological Univ., School of Mechanical and Production Engineering, Nanyang (Singapore); Zhou, P.L. [Newcastle upon Tyne Univ., Dept. of Marine Technology, Newcastle upon Tyne (United Kingdom)

    2000-10-01

    Modelling of cold-start engine exhaust behaviour is a difficult task as it involves complicated heat transfer processes associated with water condensation and evaporation at the walls of the exhaust manifold/pipe and monolith cells, and the chemical reactions of CO/HC/NO in the three-way catalytic converter. This paper presents a model that is capable of predicting the exhaust gas temperatures along the exhaust system and across the catalyst monolith, both spatially and temporally, from the moment when the engine is cranked. The conversions of CO/HC/NO to harmless carbon dioxide, water and nitrogen at the catalytic converter downstream have been validated satisfactorily by the experimental data. The distortion of measured NO emission data/signals due to the dynamic behaviour of the chemiluminescence analyser has been reconstructed by means of a signal inference technique before these signals were used to validate the predictive capability of the model developed. (Author)

  15. The SINOx catalytic converter for diesel engines, the optimum exhaust purification system for industrial vehicles; Der SINOx-Dieselkatalysator - das zukunftsweisende Abgasreinigungssystem fuer Lkw

    Energy Technology Data Exchange (ETDEWEB)

    Doelling, W.; Mathes, W. [Siemens AG, Redwitz (Germany)

    1997-07-01

    The SINOx catalytic converter system was developed by Siemens in cooperation with Iveco, Mercedes Benz and MAN. It removes nitric oxides and hydrocarbons from exhaust and reduces the number of particulate emissions. The SINOx catalytic converter system, which is currently being tested on the road, turns the diesel engine into an economical and clean drive system with good future prospects. (orig./AKF) [Deutsch] Das von Siemens in Zusammenarbeit mit Iveco, Mercedez Benz und MAN entwickelte SINOx-Katalysatorsystem beseitigt neben diesen Stickoxiden auch die Kohlenwasserstoffe aus dem Abgas und laesst die Partikelmasse sinken. Mit dem z.Z. im Strassentest befindlichen SINOx-Katalysator ist der Dieselmotor ein wirtschaftlicher und sauberer Antrieb fuer die Zukunft. (orig./AKF)

  16. Three-dimensional distribution analysis of platinum, palladium and rhodium in auto catalytic converters using imaging-mode laser-induced breakdown spectrometry

    Science.gov (United States)

    Lucena, Patricia; Laserna, J. Javier

    2001-02-01

    Laser-induced breakdown spectrometry (LIBS) is reported here as an effective technique to describe the volume distribution of platinum, rhodium and palladium in catalytic converters installed in motor vehicles. Using the second harmonic output of a Nd:YAG laser and a CCD-based atomic emission spectrometer, LIBS is used in multielemental, imaging-mode to permit the simultaneous analysis of the several elements present in the converter, including the internal standard. The data are reported with a lateral resolution of 1.75 mm over a fresh catalytic structure which is 128 mm long. The concentrational variability of the platinum group metals (PGMs) varies in the range ˜3-23% relative standard deviation depending on the element, the substrate and the direction investigated. The causes of the dispersion observed are discussed.

  17. Comparative Studies on Performance Parameters and Exhaust Emissions from Two Stroke Copper Coated Spark Ignition Engine with Alcohol Blended Gasoline with Catalytic Converter

    OpenAIRE

    S. Narasimha Kumar*1; M.V.S. Murali Krishna; P.V.K.Murthy

    2014-01-01

    Experiments were conducted to evaluate the performance and control the exhaust emissions from two-stroke, single cylinder, spark ignition (SI) engine, with alcohol blended gasoline (80% gasoline, 10% methanol, 10% ethanol by volume) having copper coated combustion chamber [CCCC, copper-(thickness, 300 µ) coated on piston crown, inner side of cylinder head] provided with catalytic converter with sponge iron as catalyst and compared with conventional SI engine (CE) with pure gas...

  18. Environmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Moldovan, M.; Palacios, M.A.; Gomez, M.M. [Departamento de Quimica Analitica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040- Madrid (Spain); Morrison, G.; Rauch, S. [Chalmers University of Technology, Gothenburg (Sweden); McLeod, C.; Ma, R. [University of Sheffield, Sheffield (United Kingdom); Caroli, S.; Alimonti, A.; Petrucci, F.; Bocca, B. [Istituto Superiore di Sanita, Rome (Italy); Schramel, P.; Zischka, M. [GSF National Research Centre for Environment and Health, Neuherberg (Germany); Pettersson, C. [Scandiaconsult Sverige AB, Gothenburg (Sweden); Wass, U. [Volvo Technological Development Corporation, Gothenburg (Sweden); Luna, M. [Ford, Madrid (Spain); Saenz, J.C. [INTA Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Santamaria, J. [Seat, Barcelona (Spain)

    2002-09-16

    A comparison of platinum-group element (PGE) emission between gasoline and diesel engine catalytic converters is reported within this work. Whole raw exhaust fumes from four catalysts of three different types were examined during their useful lifetime, from fresh to 80000 km. Two were gasoline engine catalysts (Pt-Pd-Rh and Pd-Rh), while the other two were diesel engine catalysts (Pt). Samples were collected following the 91441 EUDC driving cycle for light-duty vehicle testing, and the sample collection device used allowed differentiation between the particulate and soluble fractions, the latter being the most relevant from an environmental point of view. Analyses were performed by inductively coupled plasma-mass spectrometry (ICP-MS) (quadrupole and high resolution), and special attention was paid to the control of spectral interference, especially in the case of Pd and Rh. The results obtained show that, for fresh catalysts, the release of particulate PGE through car exhaust fumes does not follow any particular trend, with a wide range (one-two orders of magnitude) for the content of noble metals emitted. The samples collected from 30000-80000 km present a more homogeneous PGE release for all catalysts studied. A decrease of approximately one order of magnitude is observed with respect to the release from fresh catalysts, except in the case of the diesel engine catalyst, for which PGE emission continued to be higher than in the case of gasoline engines. The fraction of soluble PGE was found to represent less than 10% of the total amount released from fresh catalysts. For aged catalysts, the figures are significantly higher, especially for Pd and Rh. Particulate PGE can be considered as virtually biologically inert, while soluble PGE forms can represent an environmental risk due to their bioavailability, which leads them to accumulate in the environment.

  19. Effect of support on a catalytic converter for removing CO and HC emissions from a two-stroke motorcycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.H.; Chen, Y.W. [National Central Univ., Chungli (Taiwan, Province of China). Dept. of Chemical Engineering

    1997-12-01

    The effect of support on the noble metal catalysts for carbon monoxide and hydrocarbon oxidation was investigated. The reactions were performed under the stoichiometric and oxygen-deficient conditions. Under the stoichiometric point, the activities of the powder catalysts for CO and C{sub 3}H{sub 6} oxidation are in the order Pt/K{sub 2}O/Al{sub 2}O{sub 3} > Pt/Al{sub 2}O{sub 3} > Pt/Al{sub 2}O{sub 3}-SiO{sub 2}, that is, the same as the order of basicity of these catalysts. Under an oxygen-deficient condition, Pt supported on an acidic support, Al{sub 2}O{sub 3}-SiO{sub 2}, exhibits the higher C{sub 3}H{sub 6} conversion and the higher activity for the steam re-forming reaction. In contrast, Pt supported on a basic support, K{sub 2}O/Al{sub 2}O{sub 3}, exhibits the higher CO conversion and the higher activity for the water-gas shift reaction. The order of activity of the powder catalysts for the water-gas shift reaction is the same as the order of basicity of these catalysts. On the other hand, the testing results of the monolithic PtRh-containing catalysts by the simulative gases and the ECE-40 mode driving cycle also reveal the same trend as that of the Pt powder catalysts. Furthermore, the addition of K{sub 2}O on PtRh/Al{sub 2}O{sub 3}-CeO{sub 2} not only increases the basicity of the catalyst but also significantly reduces the CO emission under the ECE-40 mode driving cycle test. Therefore, K{sub 2}O could be a promising additive to a catalytic converter of a two-stroke motorcycle since it can significantly enhance CO conversion.

  20. INTEGRATION AND DEVELOPMENT OF NATIONAL AUTOMOTIVE CATALYTIC CONVERTER%TJ7131U轿车国产催化转化器系统的集成与开发

    Institute of Scientific and Technical Information of China (English)

    王务林; 赵航; 张春龙; 周荣; 齐欣

    2001-01-01

    Now automotive catalytic converters in China mainly rely on imports because the converter made in our country has still many problems such as matching. A kind of catalytic converter for TJ7131 is developed. The catalytic converter system performance and reliability are evaluated. It is shown that this kind of catalytic converter system has perfect purging and matching performance, and bears reliability of 50 000 km; meanwhile shows that the exhaust emission of the TJ7131 installed the catalytic converter can reach ECE R Ⅱ emission standard and the synthesis characteristic of the catalytic converter is prior to the importing one.%针对TJ71731型轿车,系统集成开发出国产催化转化器,并对所开发的催化转化器系统进行了较为系统的性能与可靠性评价。研究结果表明所开发的催化转化器系统对TJ7131型轿车具有很好的净化性能、其与整车匹配性能良好并已经具有5万km的可靠性寿命;安装该催化转化器的夏利轿车排放达到了欧洲2号法规,其综合性能优于国外进口产品。

  1. Comparison of Properties of Tumor Necrosis Factor-α Converting Enzyme (TACE) and Some Matrix Metalloproteases (MMPs) in Catalytic Domains

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The crystal structural data of TACE, MMP-1, MMP-2, MMP-3 and MMP-9 were obtained from PDB database, and then their catalytic domains' properties including conformation, molecular surface hydrophobicity and electrostatic potential were analyzed and compared by using Insight Ⅱ molecular modeling software. It was found that the conformation and molecular surface hydrophobicity of catalytic domains of TACE and MMPs were not obviously different, but the molecular surface electrostatic potential of catalytic domain of TACE and MMPs had obvious differences.The findings are helpful in the Rational Drug Design of TACE selective inhibitor.

  2. Reducing cold-start emission from internal combustion engines by means of a catalytic converter embedded in a phase-change material

    Energy Technology Data Exchange (ETDEWEB)

    Korin, E. [Ben-Gurion Univ. of the Negev, Dept. of Chemical Engineering, Beer-Sheva (Israel); Reshef, R.; Tschernichovesky, D.; Sher, E. [Ben-Gurion Univ. of the Negev, Dept. of Mechanical Engineering, Beer-Sheva (Israel)

    1999-11-01

    Under normal operating conditions, catalytic converters appear to be the most effective means of reducing air pollution from internal combustion (IC) engines. The conversion efficiency, however, declines very steeply for temperatures below about 350degC and is practically zero during the starting and warming-up period. Improving the conversion efficiency under these conditions is important, particularly in large cities, where the number of startings per vehicles per day tend to be high. Among the more successful solutions are preheating of the catalyst electrically, warming up of the catalyst in an external combustion chamber, installation of an auxiliary small-capacity catalytic converter, and employment of an adsorbing unit between two catalysts. Although these methods are quite effective, their disadvantage lies in the fact that they require an external energy source, an additional component (a control unit) or a three-stage catalyst. In the present work an investigation was made of a solution based on the exploitation of thermal capacitance to keep the catalyst temperature high during off-operation periods. A phase-change material (PCM) with a transition temperature of 352.7degC, which is slightly above the light-off temperature of the metallic catalyst, was specially formulated, and a system comprising a catalytic converter embedded in the PCM was designed and tested. Under normal engine operating conditions, some of the thermal energy of the exhaust gases was stored in the PCM. During the time that the vehicle was not in use, the PCM underwent partial solidification, and the latent heat thus produced was exploited to maintain the catalyst temperature within the desired temperature range for maximum conversion efficiency. (Author)

  3. The Effect of a Three-Way Catalytic Converter on Particulate Matter from a Gasoline Direct-Injection Engine During Cold-Start

    OpenAIRE

    Whelan, Ian; Timoney, David; Smith, William; et al

    2013-01-01

    This work investigates the effect of a three-way catalytic converter and sampling dilution ratio on nano-scale exhaust particulate matter emissions from a gasoline direct-injection engine during cold-start and warm-up transients. Experimental results are presented from a four cylinder in-line, four stroke, wall-guided direct-injection, turbo-charged and inter-cooled 1.6 litre gasoline engine. A fast-response particulate spectrometer for exhaust nano-particle measurement up to 1000 nm was util...

  4. Fault detection and maintenance of automotive three way catalytic converter%汽车三元催化器故障的检测和维护

    Institute of Scientific and Technical Information of China (English)

    袁日胜; 刘培君

    2011-01-01

    The automotive three way catalytic converter structure, purification principle, fault causes and detection method, the routine notice,etc, are introduced for reference of auto repair personnel.%探讨三元催化器减少汽车尾气的方法,着重介绍了三元催化器的结构、净化原理、产生故障原因及检测方法、日常使用注意事项等内容,供汽车维修人员参考。

  5. The performance of a monolithic catalytic converter of automobile exhaust gas with oscillatory feeding of CO, NO, and O{sub 2}. A modelling study

    Energy Technology Data Exchange (ETDEWEB)

    Nievergeld, A.J.L.; Hoebink, J.H.B.J.; Marin, G.B. [Lab. voor Chemische Technologie, Eindhoven Univ. of Technology, Eindhoven (Netherlands)

    1995-12-31

    An isothermal monolithic catalytic converter of automobile exhaust gas was modelled in order to assess the effects of oscillatory feeding of CO, O{sub 2} and NO on the performance of the reactor. The influence of the temperature, frequency, and amplitude on the time average conversions was investigated. An improvement relative to the steady state conversion of 8% for CO and 30% for NO can be obtained. An explanation is given in terms of strongly changing surface coverage during cycling of the feed concentrations. 9 figs., 5 tabs., 16 refs.

  6. Numerical Simulation of Catalytic Converter ignition Characteristics%车用催化转化器起燃特性的数值模拟

    Institute of Scientific and Technical Information of China (English)

    高伟; 孙希

    2015-01-01

    In this paper, the two-dimensional geometric model and finite element of carrier single channel of a catalytic converter was established by using ANSYS Workbench software. In FLUENT software by using laminar flow finite-rate turbulence model, the ignition characteristics of catalytic converter was numerical simulated. The temperature、flow rate、pressure and the changing process of exhaust gas components in carrier was analyzed.These results basically reflect the actual situation of catalytic converter ignition process.The trend of velocity field, temperature field, pressure field and gas components mass fraction distribution are correct and reasonable. On the basis, The impact of carrier parameters on the catalytic converter ignition characteristic and conversion efficiency were analyzed.The inlet velocity and temperature of carrier were optimized.The simulated results show that the exhaust gas conversion rate increases with the increasing temperature of the inlet. When the inlet speed increases, exhaust gas conversion rate increases first and then reduces.%利用ANSYS Workbench软件建立某催化转化器载体单孔道二维几何模型及有限元模型,在FLUENT软件中,采用层流有限速率湍流模型,对其起燃特性进行了数值模拟,分析了载体内温度、流速、压力及尾气各气体组分的变化过程,基本上反映了催化转化器起燃过程的实际情况,所得到的速度场、温度场、压力场和各组分质量分数分布图趋势均正确合理。在此基础上,分析了载体参数对催化转化器起燃特性和转化效率的影响,并对载体入口速度和温度进行了优化设计。结果表明,尾气各气体转化率随着入口温度的增加而增加,当入口速度增加时,尾气各气体转化率先增加后减小。

  7. Study on the best packaging technology of catalytic converter%催化转换器最优封装工艺研究

    Institute of Scientific and Technical Information of China (English)

    徐火青; 齐喜岑; 李金阁; 句孝飞

    2012-01-01

    In this paper,the results of the temperature fields were applied to the mechanical field with thermal-mechanical coupled, which based on the welding thermo-elastic-plastic finite element analysis theory,taking into account the material mechanical properties with temperature and strain hardening.The welding residual stress fields and the welding deformation of three catalytic converters were simulated by SYSWELD.Finally,three catalytic converters were compared from the welding residual stress,welding deformation,manufacturing time and hot-crack resistance, and the better manufacturing technology was proposed.%通过热-力单向耦合,将温度场结果施加到应力场上,依据焊接热弹塑性有限元分析理论,考虑到材料随温度变化的力学性能以及材料的应变强化,对三种封装工艺的催化转换器进行应力和变形的数值模拟.最后,从残余应力、变形、封装时间和焊缝抗热裂性等方面对比三种封装工艺的催化转换器,从实际生产效率和产品质量的角度,得出较好的封装焊接工艺.

  8. In situ deposition of silver and palladium nanoparticles prepared by the polyol process, and their performance as catalytic converters of automobile exhaust gases

    Science.gov (United States)

    Bonet, F.; Grugeon, S.; Herrera Urbina, R.; Tekaia-Elhsissen, K.; Tarascon, J.-M.

    2002-04-01

    In situ deposition of silver particles onto alumina and palladium particles onto mixed CeZr oxides has been achieved upon chemical reduction of the corresponding metal species (AgNO 3 and PdCl 2) by ethylene glycol in the presence of polyvinylpyrrolidone. The support oxide powders were found to keep their crystalline structure and morphology after treatment with hot ethylene glycol while the BET surface area decreased after metal deposition. Microprobe maps obtained from energy dispersive X-ray analysis revealed a homogeneous distribution of metal nanoparticles on the surfaces of alumina and of the mixed CeZr oxides. Supported silver and palladium were tested as catalytic converters of simulated exhaust automobile gases. The catalytic activity of silver-loaded alumina powder catalyst for CO and hydrocarbon oxidation as well as NO and NO x reduction, was found to be higher than that of a reference silver catalyst. Palladium-loaded mixed CeZr oxides powder catalyst showed a similar performance to that of a reference palladium catalyst as a three-way catalyst converter.

  9. Study on Noise Characteristics of Vehicle Catalytic Converters%基于GT-Power的车用催化器消声特性研究

    Institute of Scientific and Technical Information of China (English)

    芮鹏飞; 刘志恩; 颜伏伍; 谢志清

    2012-01-01

    This article conducts an experiment test and simulation researches on one section of vehicle catalytic converters. Using white noise test method to obtain its transmission loss and realizing simulation analysis of its sound characteristics based on GT-Power software. Experimental results show that catalytic converters have obvious silencer band and pass-by noise. The top sound attenuation reaches 20 dB. The transmission plot of single-pipe model which has the same porosity with the converter is close to the experimental plot, however, with lower attenuation. The porosity, number and diameter of pipes in the carrier have important influence on transmission loss. Double bed converter has higher TL than single bed. TL of double level converters also increases a lot than single level, which improves sound attenuation obvious-ly.%对一款车用催化器的消声特性进行了试验测试和仿真研究.利用白噪声测试法获得其传声损失,基于GT-Power软件实现了对其声学性能的仿真分析.试验结果表明催化器具有明显的消声频段和通过噪声,峰值消声量可达到20 dB;与催化器孔隙率相等的单管催化器模型传声损失曲线形状与试验结果接近,但消声量偏低;催化器载体的孔隙率以及管径、管数对传声损失有重要影响;双床催化器较单床催化器传声损失有较大提高,两级催化器较单级催化器传声损失也有很大的提高,消声特性改善明显.

  10. Development of FD Catalytic Converter for Super Ultra Low Emission (SULE) Standards%满足超低排放要求的FD净化器研制

    Institute of Scientific and Technical Information of China (English)

    肖益鸿; 蔡国辉; 郑勇; 魏笑峰; 魏可镁

    2011-01-01

    福州大学化肥催化剂国家工程研究中心研制出多种尾气净化用高性能纳米复合材料,并应用组合技术开发成功的FD净化器能满足欧Ⅳ、欧V等超低排放的要求.%National Engineering Research Center of Chemical Fertilizer Catalyst at Fuzhou University has developed many kinds of high performance nano-composite materials used for automotive emission purification. The catalytic converters which were made of these materials with compounding technology can meet the EURO phase IV and V Super Ultra Low Emission legislation limits.

  11. Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions

    Energy Technology Data Exchange (ETDEWEB)

    Buenger, Juergen; Bruening, Thomas [Ruhr University Bochum, Research Institute for Occupational Medicine of the Institutions for Statutory Accident Insurance and Prevention (BGFA), Bochum (Germany); Krahl, Juergen; Schroeder, Olaf [Federal Agricultural Research Centre, Institute of Biosystems Engineering, Braunschweig (Germany); Weigel, Andreas; Mueller, Michael; Hallier, Ernst; Westphal, Goetz [University of Goettingen, Department of Occupational and Social Medicine, Gottingen (Germany)

    2006-08-15

    Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO{sub x}), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO{sub x} with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens. (orig.)

  12. Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions.

    Science.gov (United States)

    Bünger, Jürgen; Krahl, Jürgen; Weigel, Andreas; Schröder, Olaf; Brüning, Thomas; Müller, Michael; Hallier, Ernst; Westphal, Götz

    2006-08-01

    Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO( x )), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO( x ) with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens. PMID:16555046

  13. EMISSION REDUCTION FROM A DIESEL ENGINE FUELED BY CERIUM OXIDE NANO-ADDITIVES USING SCR WITH DIFFERENT METAL OXIDES COATED CATALYTIC CONVERTER

    Directory of Open Access Journals (Sweden)

    B. JOTHI THIRUMAL

    2015-11-01

    Full Text Available This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in nanoparticle form on the major physiochemical properties and the performance of diesel. The fuel is modified by dispersing the catalytic nanoparticle by ultrasonic agitation. The physiochemical properties of sole diesel fuel and modified fuel are tested with ASTM standard procedures. The effects of the additive nanoparticles on the individual fuel properties, the engine performance, and emissions are studied, and the dosing level of the additive is optimized. Cerium oxide acts as an oxygen-donating catalyst and provides oxygen for the oxidation of CO during combustion. The active energy of cerium oxide acts to burn off carbon deposits within the engine cylinder at the wall temperature and prevents the deposition of non-polar compounds on the cylinder wall which results in reduction in HC emission by 56.5%. Furthermore, a low-cost metal oxide coated SCR (selective catalyst reduction, using urea as a reducing agent, along with different types of CC (catalytic converter, has been implemented in the exhaust pipe to reduce NOx. It was observed that a reduction in NOx emission is 50–60%. The tests revealed that cerium oxide nanoparticles can be used as an additive in diesel to improve complete combustion of the fuel and reduce the exhaust emissions significantly.

  14. Electrochemical behaviour of metal hexacyanoferrate converted to metal hydroxide films immobilized on indium tin oxide electrodes-Catalytic ability towards alcohol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: In this work, we demonstrate a simple method to modify indium tin oxide (ITO) electrodes in order to perform electro-catalytic oxidation of alcohols in alkaline medium. Metal hexacyanoferrate (MHCF) films such as nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF) were successfully immobilized on ITO electrodes using an electrochemical method. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structural and morphological aspects of MHCF films. Cyclic voltammetry (CV) was used to study the redox properties and to determine the surface coverage of these films on ITO electrodes. Electrochemical potential cycling was carried out in alkaline medium in order to alter the chemical structure of these films and convert to their corresponding metal hydroxide films. SEM and XPS were performed to analyze the structure and morphology of metal hydroxide modified electrodes. Electro-catalytic oxidation ability of these films towards methanol and ethanol in alkaline medium was investigated using CV. From these studies we found that metal hydroxide modified electrodes show a better catalytic performance and good stability for methanol oxidation along with the alleviation of CO poisoning effect. We have obtained an anodic oxidation current density of ∼82 mA cm-2 for methanol oxidation, which is at least 10 fold higher than that of any metal hydroxide modified electrodes reported till date. The onset potential for methanol oxidation is lowered by ∼200 mV compared to other chemically modified electrodes reported. A plausible mechanism was proposed for the alcohol oxidation based on the redox properties of these modified electrodes. The methodology adapted in this work does not contain costlier noble metals like platinum and ruthenium and is economically viable.

  15. Evaluation of an EMITEC resistively heated metal monolith catalytic converter on two M100 neat methanol-fueled vehicles

    Science.gov (United States)

    Piotrowski, Gregory K.; Schaefer, Ronald M.

    1992-12-01

    The report describes the evaluation of a resistively heated catalyst system on two different methanol fueled vehicles. The EMITEC catalyst consisted of a compact resistively heated metal monolith in front of a larger conventional main converter. The EMITEC catalyst was evaluated on two neat methanol-fueled vehicles, a 1981 Volkswagen Rabbit and a 1988 Toyota Corolla. Emission testing was conducted over the Federal Test Procedure (FTP) CVS-75 test cycle. The emissions of primary interest were cold start methanol (unburned fuel), carbon monoxide, and formaldehyde.

  16. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, C.A., E-mail: carlos.nogueira@lneg.pt [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Paiva, A.P., E-mail: appaiva@fc.ul.pt [Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Oliveira, P.C. [Laboratório Nacional de Energia e Geologia, I.P., Campus do Lumiar, 1649-038 Lisboa (Portugal); Costa, M.C., E-mail: mcorada@ualg.pt [Centro de Ciências do Mar, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal); Costa, A.M. Rosa da, E-mail: amcosta@ualg.pt [Centro de Investigação em Química do Algarve, Departamento de Química e Farmácia, Faculdade de Ciências e de Tecnologia, Campus de Gambelas, 8005-139 Faro (Portugal)

    2014-08-15

    Highlights: • A new leaching process based on Cu{sup 2+}/HCl media for recovering Pd and Rh from spent autocatalytic converters is presented. • Palladium and rhodium were efficiently leached, with attained maximum yields of 95% and 86%, respectively. • Temperature, time, and HCl and Cu{sup 2+} concentrations were found to be significant factors in the leaching of Pd and Rh. - Abstract: The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu{sup 2+} concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4 h, [HCl] = 6 M, [Cu{sup 2+}] = 0.3 M)

  17. Numerical Simulation of Internal Flow Field and Structure Optimization of SCR Catalytic Converter%SCR催化转化器内流场数值模拟与结构改进

    Institute of Scientific and Technical Information of China (English)

    高伟; 邓召文

    2012-01-01

    利用计算流体动力学(CFD)软件,对结构改进前后的SCR催化转化器内流场进行了三维稳态流动数值模拟,对比分析了改进前后两种不同结构的催化转化器内流动特性.模拟结果显示:结构因素对催化转化器的内流动特性有很大影响,通过结构改进,减小了压力损失,使其内部速度分布和温度分布更加均匀.%The numerical simulation of three-dimension steady state flow is carried out on the internal flow filed of SCR catalytic converters before and after structure optimization, by using the computational fluid dynamics ( CFD) code. The internal flow characteristics of two different SCR catalytic converters have been contrastively analyzed. The results show that; the structure factor has a great impact on the flow of catalytic converters. Through the improvement of structure, the pressure loss can be reduced, which makes velocity and temperature distribution in the catalytic converters to be more uniform.

  18. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters.

    Science.gov (United States)

    Nogueira, C A; Paiva, A P; Oliveira, P C; Costa, M C; da Costa, A M Rosa

    2014-08-15

    The recycling of platinum-group metals from wastes such as autocatalytic converters is getting growing attention due to the scarcity of these precious metals and the market pressure originated by increase of demand in current and emerging applications. Hydrometallurgical treatment of such wastes is an alternative way to the most usual pyrometallurgical processes based on smelter operations. This paper focuses on the development of a leaching process using cupric chloride as oxidising agent, in HCl media, for recovery of palladium and rhodium from a spent catalyst. The chloride media allows the adequate conditions for oxidising and solubilising the metals, as demonstrated by equilibrium calculations based on thermodynamic data. The experimental study of the leaching process revealed that Pd solubilisation is clearly easier than that of Rh. The factors temperature, time, and HCl and Cu(2+) concentrations were significant regarding Pd and Rh leaching, the latter requiring higher factor values to achieve the same results. Leaching yields of 95% Pd and 86% Rh were achieved under optimised conditions (T = 80 °C, t = 4h, [HCl] = 6M, [Cu(2+)] = 0.3M).

  19. Effect of K{sub 2}O on a Pd-containing catalytic converter for removing CO and HC emissions from a two-stroke motorcycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.H.; Chen, Y.W. [National Central Univ., Chung-Li (Taiwan, Province of China). Dept. of Chemical Engineering

    1998-04-01

    Noble metals (Pt, Pd, and Rh) supported on Al{sub 2}O{sub 3}, K{sub 2}/Al{sub 2}O{sub 3}, CeO{sub 2}/Al{sub 2}O{sub 3}, and K{sub 2}O/CeO{sub 2}/Al{sub 2}O{sub 3} were prepared and characterized with respect to surface area, pore volume, and temperature-programmed desorption of CO{sub 2}. The effects of K{sub 2}O on the noble-metal catalysts for carbon monoxide and hydrocarbon oxidation were investigated. The reactions were carried out under the stoichiometric and oxygen-deficient conditions. Under the stoichiometric point, the Pd-containing catalysts exhibit higher activity than the Pt-containing catalysts for both CO and C{sub 3}H{sub 6} oxidation. Moreover, Pd/K{sub 2}O/CeO{sub 2}/Al{sub 2}O{sub 3} is the most active catalyst among the powder catalysts in this study. Under the oxygen-deficient conditions and in the presence of water, the CO conversions on Pd/Al{sub 2}O{sub 3} and Pd/CeO{sub 2}/Al{sub 2}O{sub 3} are significantly lower than those on Pt/Al{sub 2}O{sub 3} and Pt/CeO{sub 2}/Al{sub 2}O{sub 3}, respectively. In contrast, the Pd-containing catalysts exhibit higher C{sub 3}H{sub 6} conversion than the Pt-containing catalysts. However, the CO conversions on the Pd-containing catalysts can be promoted by the addition of K{sub 2}O. On the other hand, the test results of the monolithic catalysts revealed that the CO conversion on PdRh/K{sub 2}O/Al{sub 2}O{sub 3}--CeO{sub 2} is quite close to that on PtRh/Al{sub 2}O{sub 3}-CeO{sub 2} under the simulative gases and the ECE-40 mode driving cycle test. PtRh/Al{sub 2}O{sub 3}-CeO{sub 2} is the typical composition of catalytic converters for two-stroke motorcycles. It infers that PdRh/K{sub 2}O/Al{sub 2}O{sub 3}-CeO{sub 2} is a promising catalytic converter for a two-stroke motorcycle.

  20. Roadside Accumulation of Pt, Pd, Rh and Other Trace Elements From Automobiles: Catalytic Converter Attrition and Platinum-Group Element Mobility in the Roadside Environment.

    Science.gov (United States)

    Ely, J. C.; Dahlheimer, S. R.; Neal, C. R.

    2003-12-01

    Elemental abundances of Pt, Pd and Rh have been documented across the industrialized world in roadside environments due to attrition of automotive catalytic converters (Zereini and Alt, 2000, Anthropogenic PGE Emissions, Springer, 308pp; Ely et al., 2001, EnvSci&Tech, 35:3816-3822; Whiteley and Murray, 2003, SciTotEnv, in press). In our ongoing study, the highest reported roadside Pt abundance 1.8 ppm has been found immediately adjacent to the road at a field site in South Bend, IN, USA. Furthermore, initial studies show positive correlations of Pt, Pd and Rh with some trace elements (Ni, Cu, Zn and Pb), which has been confirmed by further analysis for these and other elements (Ce, Cr). It has been demonstrated that elements such as Ce are present in catalytic converters at concentrations of 100's ppm to 3-wt.%. These elements are also being attrited with Pt, Pd and Rh and aerially transported and deposited. Our field site was established next to US-933 adjacent to the Notre Dame campus. Areas were cleared of the top 2-4 cm of soil (removing surficial Pt, Pd and Rh) at 1, 5, 10 and 50 meters from the roadside. Within 3 months the 1-meter site contained 67% of the initial Rh and Pt concentrations and 100% of the initial Pd concentration. The sites at 5, 10 and 50 meters showed similar results, in some cases exceeding the initial concentrations. After 6 months the concentrations of Pt, Pd and Rh were all within error of the initial concentrations, indicating steady state abundances had probably been reached. Grass samples from each site showed that washed vs. unwashed samples were within error of each other, and there may be a slight enrichment (approx. 1 ppb) in the grasses of Pd and Pt, but this enrichment was independent of distance from the road. The steady-state situation suggests that the PGEs are being removed from the immediate roadside environment, which requires that the metals are being oxidized and/or complexed in such a way to facilitate transport. The

  1. 某汽油机催化器系统的CFD分析%CFD Analysis on Catalytic Converter System of Gasoline Engine

    Institute of Scientific and Technical Information of China (English)

    王丹; 刘双喜; 牟江峰; 陈浩

    2014-01-01

    Numerical simulation of catalytic converter system for certain gasoline engine was conducted by CFD software of STAR-CCM+. By using porous media modal to simulate the internal flow of the catalyst, the pressure drop and uniformity of the flow filed were discussed,and the positions of oxygen sensors were evaluated. Based on the calculated results,optimization recommendations were pointed out. The research will provide theoretical basis for structure design and performance improvement of exhaust system.%利用三维流体分析软件STAR- CCM+对某汽油机催化器系统进行了模拟分析,运用多孔介质模型模拟催化器内部的流动,重点考察了该催化器系统的压力损失和气流分布均匀性,并对氧传感器的位置进行了评估。综合各项分析评价指标,提出优化建议,为排气系统的结构设计和性能改进提供理论依据。

  2. A methodical approach to modelling the mechanical stability of metallic catalytic converter substrates; Methodische Vorgehensweise zur Modellierung der mechanischen Stabilitaet von metallischen Katalysatortraegern

    Energy Technology Data Exchange (ETDEWEB)

    Guist, C. [Bayerische Motoren Werke AG (BMW), Muenchen (Germany)

    2000-02-01

    Simulation is gaining increasing significance in automotive development, thanks to the advantages it brings with regard to cutting costs and reducing development time. A characteristic feature of simulation is that the solution is devised on a virtual plane, irrespective of the technical taks. Translating the technical system onto the virtual plane, or the modelling process, is critical to the outcome. This aspect is considered using the example of the simulation of the mechanical stability of metallic catalytic converter substrates (EMITEC) in a close-coupled arrangement on a BMW six-cylinder engine. The objective is to highlight the approach used in this process, as it is also transferable to other engineering tasks. (orig.) [German] Die Simulation nimmt aufgrund der sich dadurch bietenden Vorteile hinsichtlich Kosteneinsparung und Entwicklungszeitverkuerzung an Bedeutung bei der Fahrzeugentwicklung zu. Charakteristisch fuer die Simulation ist, dass die Loesung, unabhaengig von der technischen Aufgabenstellung, in der virtuellen Ebene erfolgt. Die Uebertragung des technischen Systems in die virtuelle Ebene, das Modellieren, stellt den erfolgsbestimmenden Schritt dar. Dieser Aspekt soll am Beispiel der Simulation der mechanischen Stabilitaet von metallischen Katalysatortraegern (Emitec) bei motornaher Anordnung an einem BMW-Sechszylindermotor betrachtet werden. Das Ziel ist, die dabei angewandte Methodik, die sich auch auf andere technische Aufgaben uebertragen laesst, darzustellen. (orig.)

  3. Correct Used and Trouble Diagnosis of Catalytic Converter%催化转化器的正确使用及故障诊断

    Institute of Scientific and Technical Information of China (English)

    蒋耘农; 杨亚东

    2001-01-01

    The paper introduces some cautions for correct use of catalyticconverter, i.e., correct use of lubrication oil, use of superior nonleaded gasoline, keep of better automotive working status, normal working condition of electronic control system of engine, installation of over heat alarm and etc. In addition, describes the trouble diagnosis of catalytic converter by using the comparing method of double waste-gases, the comparing method of cold and heat idle speed, the temperature differential method in idle speed, the vacuum measuring method and etc.%介绍了正确使用催化转化器的一些注意事项,即正确使用润滑油,使用高品质的无铅汽油,保持发动机良好的工作状态,发动机电控系统必须正常及安装过热报警器等。另外,阐述了利用两次废气对比法、冷热怠速对比法、怠速温差法及真空测量法等方法对催化转化器的故障诊断。

  4. Effect of ethanol-diesel blend fuels on emission and particle size distribution in a common-rail direct injection diesel engine with warm-up catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwanam [Graduate School of Mechanical Engineering, Chonnam National University, Gwangju 500-757 (Korea); Choi, Byungchul [Graduate School of Mechanical Engineering, Chonnam National University, Gwangju 500-757 (Korea); School of Mechanical Systems Engineering, Chonnam National University, Gwangju 500-757 (Korea)

    2008-10-15

    In this study, the exhaust gas from a common-rail direct injection diesel engine was investigated both upstream and downstream warm-up catalytic converters (WCC). Three different types of ultra-low sulfur fuels (ethanol-diesel blend, ethanol-diesel blend with cetane improver and pure diesel) were tested in this study. The objective of the work was to study the engine performance and the formation of THC (total hydro carbon), CO (carbon monoxide), NO{sub x} (nitrogen oxides), smoke and PM (particulate matters) when using these fuels. THC and CO emissions of the ethanol-diesel blend fuels were slightly increased, and about 50-80% mean conversion efficiencies of THC and CO on catalysts were achieved in the ECE R49 13-mode cycle. Smoke was decreased by more than 42% in the entire ECE 13-mode cycles. From the measurement of scanning mobility particle sizer (SMPS) for the particle size range of 10-385 nm, the total number and total mass of the PM of the ethanol-diesel blend fuels were decreased by about 11.7-15% and 19.2-26.9%, respectively. (author)

  5. The Influence of Catalytic Converter on Benzene Emissions from Gasoline Engine%催化器对汽油机苯排放的影响

    Institute of Scientific and Technical Information of China (English)

    黎苏; 赏星耀; 李西秦; 刘冰

    2011-01-01

    Using unleaded gasoline widely in vehicles makes the emissions of harmful benzene and benzene series increase. In order to know the influence of three-way catalytic converter on emissions of benzene from gasoline combustion process, a series of tests are carried out on a HL495IQ electronic fuel injection gasoline engine. The exhaust emissions are collected by an activated carbon sampling pipe. The emissions of benzene and benzene series are measured by a gas phase chromatography. The formatting rules of benzenes are analyzed.%无铅汽油的广泛使用,使得汽油机苯及苯系物等有害物质的排放量有所增加.为了解三元催化器对汽油燃烧过程中苯及苯系物生成的影响,在HL495IQ电喷汽油机上进行了一系列试验.通过活性炭采样管收集尾气中的排放物,经气相色谱仪分析得到苯及苯系物的排放量,并对其生成规律进行了分析.

  6. Uptake and bioaccumulation of platinum group metals (Pd, Pt, Rh) from automobile catalytic converter materials by the zebra mussel (Dreissena polymorpha).

    Science.gov (United States)

    Zimmermann, Sonja; Messerschmidt, Jürgen; von Bohlen, Alex; Sures, Bernd

    2005-06-01

    The uptake and bioaccumulation of the platinum group metals (PGM) platinum (Pt), palladium (Pd), and rhodium (Rh) by the zebra mussel (Dreissena polymorpha) were investigated in exposure studies using ground material from unused automobile catalytic converters as metal source. The mussels were exposed to the metals in tap water or humic water. In the soft tissue samples of exposed mussels mean Pt levels ranged in dependence on the type of tank water and the exposure period (6, 9, or 18 weeks) between 780 and 4300 ng/g, the Pd levels ranged between 720 and 6300 ng/g, and the Rh levels ranged between 270 and 1900 ng/g. In contrast, the control mussels had metal concentrations of <20 ng/g (Pt), <50 ng/g (Pd), and <40 ng/g (Rh). Considerably higher PGM levels were found in the exposed mussels of the humic water group than in those of the tap water group. Although there is a cumulative increase of the PGM concentrations in the environment since the introduction of the automobile catalyst more than 20 years ago, only little information about the PGM contamination in the biosphere, especially the fauna, is available. Due to the high capacity of D. polymorpha to accumulate PGM, this bivalve could be used as a potential sentinel for monitoring the noble metals in aquatic ecosystems. PMID:15820726

  7. Emission reduction efforts in Germany. First catalytic converter for diesel engines in industrial vehicles and cogeneration systems; Deutschland ist kein Russ-Land. Erster Diesel-Kat fuer Nutzfahrzeuge und Blockheizkraftwerke

    Energy Technology Data Exchange (ETDEWEB)

    Lossau, N.

    1998-09-01

    Diesel engines still have too high emissions of nitric oxides and soot. Siemens engineers have developed a catalytic converter for large-volume diesel engines and were awarded the Philip Morris research award for it. The new catalytic converter will be installed in the Berlin Reichstag building to purify the emissions of the building`s cogeneration system. (orig.) [Deutsch] Noch geben die Dieselmotoren in Lastwagen und Blockheizkraftwerken zu viel Stickoxide und Russ ab. Um zu verhindern, dass Deutschland ein Russ-Land bleibt, haben Siemens-Forscher einen Katalysator fuer grossvolumige Dieselmotoren entwickelt und dafuer den Philip Morris Forschungspreis erhalten. Dieser Katalysator wird kuenftig sogar die Abgase des Blockheizkraftwerkes im Berliner Reichstagsgebaeude reinigen. (orig.)

  8. Comment on 'Artificial neural network based modeling of heated catalytic converter performance' by M. Ali Akcayol and Can Cinar [Applied Thermal Engineering 25 (2005) 2341

    Energy Technology Data Exchange (ETDEWEB)

    Sha, W. [Metals Research Group, School of Planning, Architecture and Civil Engineering, The Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom)

    2007-02-15

    A paper has been published in Applied Thermal Engineering, using feed-forward artificial neural network (ANN) in the modeling of heated catalytic converter performance. The present paper attempts to discuss and comment on the paper. The amount of data used in the paper are not enough to determine the number of fitting parameters in the network. Therefore, the model is not mathematically sound or justified. The conclusion is that ANN modeling should be used with care and enough data. (author)

  9. Development of oxidation resistance Fe-Cr-Al alloy for substrate of catalytic converter; Shokubai tantaiyo taisankasei Fe-Cr-Al gokinhaku no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, K.; Kono, M.; Shimizu, H.; Togashi, F.; Kawasaki, T. [Kawasaki Steel Corp., Tokyo (Japan)

    1993-10-01

    Development has been made on an Fe/20Cr/5Al/0.08La/0.03Zr alloy having excellent oxidation resistance and manufacturability as a carrier for catalytic converter used for exhaust gas purification. This paper describes the course of the development. In an experiment, steel lumps with different compositions were repeated with hot rolling, cold rolling after annealing, and annealing to make them into foils. Oxidation experiment, impact experiment, and quantitative analysis were carried out. The relation between La addition and oxidation resistance was discussed. Increasing the addition amount improves the oxidation resistance, but an addition higher than 0.10% would cause it to deposit on grain boundaries resulting in cracks. Looking at the relation of oxidation with Ti and Zr, Ti reduces the oxidation resistance, but Zr improves it, the result having been obtained at 1150{degree}C. As a result of discussing the oxidation resistance from an La/Zr composite addition viewpoint, it was revealed that the oxidation resistance decreases when the Zr addition exceeds a limit. The reason for this was inferred that an addition in excess of the 0.1% limit causes an existence of solid solution of Zr to form ZrO2, which would accelerate diffusion rate of oxygen. A discussion was given on the relation between tenacity reduction as a cause of breakage and elements. It was determined that a condition for good tenacity is that Zr/(C+N) (atom ratio) is from one to 1.5 from data of temperatures at which the impact test value becomes 5 {times} 10{sup 5} J/m{sup 2}. 11 refs., 10 figs., 1 tab.

  10. 三元催化转换器壳体结构改进与试验研究%Experimental Study and Structure Improvement on the Shell of Three-way Catalytic Converter

    Institute of Scientific and Technical Information of China (English)

    王银山; 石传龙; 岳东鹏; 贾同国

    2011-01-01

    The shell of three-way catalytic converter is designed for improving. The front cone has two expanding angles in order to make more uniform of the speed of before entering the carrier of three-way catalytic converter, because the length of the expanding part is shortened so as to decrease the gas expanding room. So both the conversion efficiency and Service Life are improved. Two terminals of the shell are necked in order to reduce the gas striking against the end of substrate and prevent it from coming off early. The experiment results show that the improved three-way catalytic converter can reduce HC, CO and NOx emission further, especially during the high load operation. The power and fuel economy are also improved.%对三元催化转换器壳体结构进行改进,前端锥采用两个扩张角,缩短了扩张角的长度,壳体两端采用缩颈处理,减少了排气气流对衬垫端面的冲击.试验结果表明,改进后的三元催化转换器,对HC、CO和NOx的转换效率得到提高,且大负荷工况下效果明显,而对发动机的燃油消耗率和功率基本没有影响.

  11. Maintenance of Engine From Analysis of Three-way Catalytic Converter Fault Diagnosis%从三元催化器故障分析发动机的保养注意事项

    Institute of Scientific and Technical Information of China (English)

    闫云敬

    2016-01-01

    Three-way catalytic converter is the gas purification device in the automobile exhaust system,once damaged,it will bring higher maintenance costs to the owner.Through fault analysis of several car three-way catalytic converter,this article put forward several maintenance measures to avoid and solve three-way catalytic converter faults in view of the failure phenomenon and failure mechanism.%三元催化器,是安装在汽车排气系统中的机外净化装置,一旦损坏,将会给车主带来比较高的维修费用通过对几款车三元催化器故障分析,针对故障现象、故障机理,提出了避免和解决三元催化器故障的发动机保养注意事项。

  12. 从三元催化器故障分析发动机的保养注意事项%Maintenance of Engine From Analysis of Three-way Catalytic Converter Fault Diagnosis

    Institute of Scientific and Technical Information of China (English)

    闫云敬

    2016-01-01

    Three-way catalytic converter is the gas purification device in the automobile exhaust system,once damaged,it will bring higher maintenance costs to the owner.Through fault analysis of several car three-way catalytic converter,this article put forward several maintenance measures to avoid and solve three-way catalytic converter faults in view of the failure phenomenon and failure mechanism.%三元催化器,是安装在汽车排气系统中的机外净化装置,一旦损坏,将会给车主带来比较高的维修费用通过对几款车三元催化器故障分析,针对故障现象、故障机理,提出了避免和解决三元催化器故障的发动机保养注意事项。

  13. An Experimental Study on the Performance Matching of Urea-SCR Catalytic Converter with Engine%尿素-SCR催化器与发动机性能匹配试验研究

    Institute of Scientific and Technical Information of China (English)

    郭红松; 姜艳; 包俊江; 景晓军

    2011-01-01

    A power, fuel economy and emission performances matching test is conducted on a stage-IV heavy duty diesel engine equipped with 3 typical commercial urea-SCR catalytic converters produced by different manufacturers, focusing on the study on performances including pressure drop and light-off characteristics as well as the dynamic response and pollutant conversion rates of catalytic converter. The results show that the fewer the mesh number of converter, the smaller its pressure drop; the catalytic converter with lower light-off temperature and quicker dynamic response has better control result for not only NOX, but also NH3, SO2, N2O and NO2. With same size and structure of SCR, the formula and coating process of catalyst basically have no effects on the power and fuel e-conomy of engine.%对一台国IV重型柴油机装用不同厂家生产的3种典型商用尿素-SCR催化转化器在台架上进行了动力性、经济性和排放等性能匹配试验,重点研究催化转化器的压降特性、起燃特性、动态响应和转化效率等性能.结果表明,催化器目数越少,其压降越小;起燃温度低,动态响应快的催化器具有较好的NOx控制效果,且在减少NH3、SO2、N2O和NO2排放方面效果也较好.SCR尺寸和结构相同时,发动机动力性和经济性基本不受催化剂配方和涂层工艺的影响.

  14. Low-pollution operation of diesel engines. New catalytic converter system reduces all pollutant fractions; Dieselmotoren schadstoffarm betreiben. Neues Katalysatorsystem vermindert alle Schadstoffkomponenten

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, B. [HJS Fahrzeugtechnik GmbH und Co., Menden (Germany). Bereich Entwicklung

    1998-07-01

    An exhaust treatment system for diesel engines is currently being developed which will reduce CO, HC, particulate and NO{sub x} emissions efficiently. For the first three (Ch, HC and particulates), the CRT particle filter system has been in use for three years now with good results. The CRT system combines a diesel particulate filter with an upstream high-efficiency oxidation catalyst. In order to account for nitric oxides as well, the soot filter system must be combined with a denox catalyst working b the SCR process in which nitric oxides are reacted with ammonia into nitrogen and water. The ammonia is generated in gaseous form by an onboard generator. The envisaged combination of a CRT system with an SCR catalytic converter will be called SCRT system. The SCRT system will be able to reduce all limited pollutant fractions at once. Results so far show that hydrocarbons, carbon monoxide and particulates are reduced down to below the detection limit. Reduction of nitric oxides is in the 75% range, so that the Euro II engine will have nitric oxide emissions of less than 2 g/kWh in the 13-stage test. (orig.) [Deutsch] Fuer Fahrzeuge mit Dieselmotoren wird derzeit ein Abgasnachbehandlungssystem entwickelt, das die Schadstoffkomponenten CO, HC und Partikel sowie die Stickoxide (NO{sub x}) mit hohem Wirkungsgrad absenkt. Zur Verminderung der CO-, HC- und Partikelemissionen ist das seit drei Jahren eingesetzte CRT-Partikelfiltersystem geeignet. Das CRT-System ist die Kombination eines Dieselpartikelfilters mit einem vorgeschalteten hocheffizienten Oxidationskatalysator. Um gleichzeitig die Stickoxidemission zu vermindern, muss das Russfiltersystem mit einem Denox-Katalysator kombiniert werden. Die Umwandlung dieser Schadstoffe erfolgt nach dem SCR-Verfahren. Dabei werden die Stickoxide durch Zugabe von Ammoniak an einem SCR-Katalysator gezielt zu Stickstoff (N{sub 2}) und Wasser (H{sub 2}O) umgesetzt. Das Ammoniak wird in einem Generator an Bord des Fahrzeugs in

  15. A Study on the Application of Catalytic Converters for the In-Used Gasoline Vehicle%在用汽油车催化转化器的若干应用研究

    Institute of Scientific and Technical Information of China (English)

    罗玮; 韦安和; 陈特銮; 谢金料; 吴坚

    2001-01-01

    As the pollution of vehicle exhaust gas has grown worse, and thestandards of emissions have become more and more strict, the technology of exhaust emission control has been developed greatly.The application of catalytic converter constitutes the mainstream of emission control technology.Grounded on the up-to-date domestic and foreign technologies of catalytic converters and the situation of their application, this paper presents several better solutions to the control on vehicle exhaust emissions in our country.%随着汽车尾气污染的日益严重及汽车尾气排放标准的日益严格,排放控制技术有了很大发展,尾气催化净化技术成为排放控制技术的主流.文中针对目前国内催化转化器的技术及应用状况,并借鉴国外有关技术,提出了我国在用汽油车排放控制的有关对策.

  16. An Experimental Study on the Fast Light Off of Catalytic Converter in a Gasoline Direct Injection Engine%直喷汽油机催化器快速起燃的试验研究

    Institute of Scientific and Technical Information of China (English)

    于秀敏; 董伟; 嵇全喜

    2011-01-01

    针对EA888直喷汽油机建立了试验台架及试验测控系统,通过试验研究了过量空气系数和两次喷射比例对催化器起燃特性的影响规律.试验结果表明,采用微稀的混合气有利于催化器的快速起燃,采用两次喷射有助于推迟点火,提高排气温度,缩短催化器起燃时间.%A test bench and its control system are established for EA888 direct injection gasoline engine, and an experimental study is conducted on the rule of the effects of excess air coefficient and the fuel proportion ratio in two-stage fuel injection on the light-off characteristics of catalytic converter. The results show that a slight-lean mixture is conducive to the rapid light off of catalytic converter, and two-stage injection helps delay ignition, raise exhaust temperature and shorten the light-off time of catalyst.

  17. 基于发动机外特性实验的三元催化转换器净化性能研究%Experimental Study on Purification Performance of Three-way Catalytic Converter Based on the External Characteristics of Engine

    Institute of Scientific and Technical Information of China (English)

    李欣; 杜慧起

    2012-01-01

    文章通过发动机外特性实验,分别对没有安装催化器、安装原催化器和安装改进型催化器三种状态下发动机功率、油耗和尾气进行测量分析,对优化三元催化转化器结构设计及改善三元催化转化器净化效率等方面具有重要意义。%through the external characteristic experiment of the engine,the article measures and analyzes the engine power,fuel consumption and exhaust respectively under the three states of not being fitted with catalytic converters,installation of the original catalytic converters and installation of improved catalytic converters,which is of great significance to the optimization of the structure design of the three-way catalytic converter and the efficiency of improving the purification of the three-way catalytic converter.

  18. Session 6: Novel catalytic converter with low light off temperature based on LaNiO{sub 3} perovskite synthesized from Raney Ni

    Energy Technology Data Exchange (ETDEWEB)

    Hamedmonfared, A.A.; Khodadadi, A.A.; Mortazavi, Y. [Tehran, Univ., Catalysis and Reaction Eng. Lab., Chemical Eng. Dept.(Iran, Islamic Republic of); Tousi, F. [Tehran, Univ., Dept. of chemistry, Faculty of Science (Iran, Islamic Republic of)

    2004-07-01

    In the present investigation we use Raney nickel catalyst to prepare LaNiO{sub 3} perovskite with and without the use of citric acid. The performance of these catalysts was compared with other types of LaNiO{sub 3} made by conventional preparation methods, in which nitrate solutions of nickel and lanthanum are used. The catalytic activities of the catalysts were studied by using a simulated exhaust gas, containing carbon monoxide and ethane. (authors)

  19. EMISSION REDUCTION FROM A DIESEL ENGINE FUELED BY CERIUM OXIDE NANO-ADDITIVES USING SCR WITH DIFFERENT METAL OXIDES COATED CATALYTIC CONVERTER

    OpenAIRE

    B. JOTHI THIRUMAL; E, JAMES GUNASEKARAN; LOGANATHAN; C.G. Saravanan

    2015-01-01

    This paper reports the results of experimental investigations on the influence of the addition of cerium oxide in nanoparticle form on the major physiochemical properties and the performance of diesel. The fuel is modified by dispersing the catalytic nanoparticle by ultrasonic agitation. The physiochemical properties of sole diesel fuel and modified fuel are tested with ASTM standard procedures. The effects of the additive nanoparticles on the individual fuel properties, the engine performanc...

  20. 草酸溶液清洗三元催化器的实践研究%Practice Research on Cleaning Three-way Catalytic Converter with Oxalic Acid Solution

    Institute of Scientific and Technical Information of China (English)

    杜慧起

    2016-01-01

    Three-way catalytic converter is one of the most important gas purification device in the automobile exhaust system,it has become a standard equipment which reaches gasoline engine achieveⅢstandards.Due to its expensive cost,low cost maintenance can bring great economic benefits to the owners.%三元催化器是安装在汽车排气系统中最重要的机外净化装置,已经成为汽油机达到国Ⅲ标准的标配。三元催化器的造价比较昂贵,对三元催化器进行低费用修复,能够给车主带来很大的经济效益。

  1. The Affecting Factors to Restrict Increasing Convert Ratio of Fluid Catalytic Cracking Unit%制约提高催化裂化转化率的影响因素分析

    Institute of Scientific and Technical Information of China (English)

    曹小伟

    2012-01-01

    通过运用催化裂化相关理论并结合惠州炼油分公司催化裂化装置的实际生产情况,对影响催化裂化转化率的因素进行了分析,通过分析各操作参数间的相互关系,确定在装置掺炼加氢尾油后,油浆系统是制约提高转化率的关键因素。%On the basis of the fluid catalytic cracking theory,the main process parameters of FCC unit in Huizhou Oil Refining Company were analyzed,that the slurry oil system was the important restrict factor to increase the convert ratio when FCC unit process the feed mixed with hydro-cracking unconverted oil.

  2. Experimental and Theoretical Study on the Flow Resistance of Automotive Catalytic Converters%车用催化器流动阻力的试验与理论研究

    Institute of Scientific and Technical Information of China (English)

    帅石金; 王建昕; 庄人隽; 陈峻锐

    2001-01-01

    在稳流试验台上利用U型管测量了不同结构催化器的压力损失,并进行了理论分析。研究表明,在小角度范围内,扩张角越大,压力损失也越大;但当锥角超过一定值之后,锥角越大,压力损失反而略有下降;在相同的扩张管长度下,斜扩张管催化器的压力损失大于直扩张管催化器的压力损失;载体位于催化器中部较顶部和底部压力损失大。%The flow resistance of automotive catalytic converter has asignificant effect on the performance of catalysts and engines. In this paper, the pressure losses of catalytic converters with various configurations have been measured by a piezometer on a steady flow rig and analyzed in theory. It can be concluded that pressure loss generally increases as cone angle of the diffuser enlarges, but has a reverse relation as the angle exceeds 60°. The declined diffuser has a larger flow resistance than conventional conical diffusers under the same length. The pressure loss of the substrate located in the middle pipe is bigger than that in the top and bottom.

  3. Nano sponge Mn₂O ₃ as a new adsorbent for the preconcentration of Pd(II) and Rh(III) ions in sea water, wastewater, rock, street sediment and catalytic converter samples prior to FAAS determinations.

    Science.gov (United States)

    Yavuz, Emre; Tokalıoğlu, Serife; Sahan, Halil; Patat, Saban

    2014-10-01

    In this study, a nano sponge Mn2O3 adsorbent was synthesized and was used for the first time. Various parameters affecting the recovery values of Pd(II) and Rh(III) were examined. The tolerance limits (≥ 90 %) for both Pd(II) and Rh(III) ions were found to be 75,000 mg L(-1) Na(I), 75,000 mg L(-1) K(I), 50,000 mg L(-1) Mg(II) and 50,000 mg L(-1) Ca(II). A 30s contact time was enough for both adsorption and elution. A preconcentration factor of 100 was obtained by using 100mg of the nano sponge Mn2O3. The reusability of the adsorbent was 120 times. Adsorption capacities for Pd(II) and Rh(III) were found to be 42 and 6.2 mg g(-1), respectively. The detection limits were 1.0 µg L(-1) for Pd(II) and 0.37 µg L(-1) for Rh(III) and the relative standard deviations (RSD, %) were found to be ≤ 2.5%. The method was validated by analyzing the standard reference material, SRM 2556 (Used Auto Catalyst Pellets) and spiked real samples. The optimized method was applied for the preconcentration of Pd(II) and Rh(III) ions in water (sea water and wastewater), rock, street sediment and catalytic converter samples. PMID:25059126

  4. Measuring the effects of platinum from catalytic converter equipped vehicles by means of plant indicators (food and fodder plants); Wirkungsmessungen von Platin aus katalysatorbetriebenen Kraftfahrzeugen mit pflanzlichen Bioindikatoren (Nahrungs- und Futterpflanzen)

    Energy Technology Data Exchange (ETDEWEB)

    Maier-Reiter, W.; Sommer, B. [TUEV Energie und Umwelt GmbH, Filderstadt (Germany). Niederlassung Stuttgart

    1997-12-31

    The essential aim of the present R and D project, titled ``Measuring the effects of platinum from catalytic converter equipped vehicles by means of plant indicators - food and fodder plants (VPT 02)``, was to obtain first orienting results on the potential effects of platinum pollution on plants by means of short-time, high-dose exposure experiments. The most important effect criterion in assessing potential hazards to humans and animals via the food chain, beside any outwardly visible changes (reaction), was the analytical detection of platinum accumulation in the plants. The project was also intended as a first contribution to the ecotoxicology of platinum, in particular the behaviour of metallic platinum and water-soluble platinum compounds in the soil-plant system. [Deutsch] Die wesentliche Zielsetzung des F and E-Vorhabens `Wirkungsmessungen von Platin und Platinverbindungen mit pflanzlichen Bioindikatoren - Nahrungs- und Futterpflanzen (VPT 02)` war es, im Rahmen von Kurzzeit-Belastungsexperimenten im hohen Dosisbereich erste orientierende Ergebnisse zu den moeglichen Auswirkungen von Platin-Belastungen auf Pflanzen abzuleiten. Neben aeusserlich sichtbaren Veraenderungen der Pflanzen (Reaktion) wurde als Wirkungskriterium insbesondere die chemisch-analytisch erfassbare Platin-Anreicherung in den Pflanzen (Akkumulation) betrachtet, die eine Abschaetzung moeglicher Gefaehrdungen von Mensch und Tier ueber die Nahrungskette ermoeglicht. Zudem sollte ein erster Beitrag zur Oekotoxikologie des Platins, insbesondere zum Verhalten von metallischem Platin und wasserloeslichen Platinverbindungen im System Boden-Pflanzen, erarbeitet werden. (orig.)

  5. 适合中国道路的车用催化器快速老化循环研究%Research on Rapid Aging Cycle of Vehicle Catalytic Converter for Chinese Road Conditions

    Institute of Scientific and Technical Information of China (English)

    业红玲

    2013-01-01

    The thermal aging mechanism of catalytic converter was first analyzed and researched ,the design idea of bench rap-id aging cycle for specific conditions was put forward ,and the bench rapid aging cycle for Chinese road conditions was devel-oped .The results show that the aging for each real vehicle can be predicted by modifying some parameters in the basic shape of developed aging cycle and adjusting the aging time .%首先对催化剂热老化原理进行了理论研究与分析,提出针对具体车用催化器使用条件的台架快速老化循环设计思路,并在试验的基础上开发出适合中国道路条件下的台架快速老化循环。结果表明,开发的老化循环在循环的基本形状上修正一些参数,调整老化时间,能预测每个车型的实车老化。

  6. The curse of the CATalytic converter.

    Science.gov (United States)

    James, E

    1997-01-01

    Addresses the transfer of nurse education from schools of nursing, previously located within health authorities and, more recently, hospital and/or community trusts, to institutions of higher education. The pressures this has produced for both providers and participants in this relatively new educational initiative have had a direct effect on the levels of stress and anxiety that students feel both in their initial professional qualification programmes and in continuing their personal and academic development subsequently. There is a paucity of research into this area of stress and student Angst as a result of the new educational thrust. Suggests that the evidence from student evaluations has not been collated adequately and that the result is a burgeoning of anecdotal evidence which is being ignored by nursing's professional body. Higher education has encouraged and influenced an almost exponential growth in programmes of study, which the nursing profession has used to force its singular aim to create a degree-based profession. PMID:10167879

  7. 基于SYSWELD催化转换器焊接温度场和应力场模拟%Numerical Simulation of Welding Temperature Field and Stress Field of Catalytic Converter Using SYSWELD Software

    Institute of Scientific and Technical Information of China (English)

    徐火青; 凌泽民; 齐喜岑; 李金阁

    2012-01-01

    依据产品几何模型,运用Visual Mesh网格划分软件分别建立了网格模型,通过对实际工艺参数和工艺特点的分析,建立了简化的数值模型,考虑了材料随温度变化的热物理性能和对流、辐射换热边界条件,给出了其焊接温度场演变历程和焊缝及其附近热循环曲线.同时实测了催化转换器焊缝附近的焊接热循环曲线,与模拟结果比较,两者基本吻合,证明了焊接温度场模拟结果的可靠性;并通过热-力耦合,将温度场结果施加到应力场,得到了残余应力分布规律,以及焊接变形量大小,与实测结果基本吻合.%Geometric models were established based on the product, and then their mesh models were built by using Visual Mesh software. Simplified numerical models were established with the analysis of actual process parameters and characteristics, which took the material properties with temperature and the heat transfer boundary conditions such as convection and radiation into account. Their temperature evolutions and thermal cycles nearby welding beads were given. Thermal cycles nearby welding beads of catalytic converter were measured, which were almost consistent with the simulation results. The welding temperature field simulations were credible. The results of the temperature fields were applied to the mechanical field with thermal-mechanical coupled. Welding residual stress fields and the welding deformation simulation results were given and analyzed quantitatively, which were almost consistent with measured values.

  8. A comparison of benzene, toluene and C{sub 2}-benzenes mixing ratios in automotive exhaust and in the suburban atmosphere during the introduction of catalytic converter technology to the Swiss Car Fleet

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, N.V.; Forss, A.-M.; Bach, C.; Reimann, S.; Herzog, A.; Jackle, H.W. [Swiss Federal Laboratories for Materials Testing and Research, Duebendorf (Switzerland)

    2000-07-01

    Time-resolved chemical ionization mass spectrometry (CIMS) has been used to investigate the variations of the mixing ratios of benzene, toluene and the C{sub 2}-benzenes (xylenes and ethyl benzene) in automotive exhaust during transient engine operation. A significant increase of the benzene/toluene ratios from 0.35 to 1.31 (median) was found upon introduction of a catalytic converter system. A preliminary emission model was developed from these test stand measurements to simulate benzene/toluene ratios of passenger car fleets with variable proportions of three-way catalyst vehicles. Although only the emissions of gasoline-driven passenger cars have been considered so far, the predicted increase of the benzene/toluene ratios during the introduction period of the three-way catalyst from 1980 to 2000 is in good agreement with the observed increase of the atmospheric benzene/toluene ratio measured at a suburban monitoring site (Dubendorf, Switzerland) which is strongly influenced by road traffic emissions. At this site, the atmospheric concentrations of benzene and alkyl benzenes have been detected at hourly intervals since 1993. A steady decrease of the yearly mean from 3.54 to 2.00 ppb for toluene and from 2.87 to 1.33 ppb for the sum of C{sub 2}-benzenes was found from 1994 to 1998, respectively, when the proportion of three-way catalyst passenger cars increased from 60 to 82%. Nevertheless, the mean benzene concentration was only affected to a small degree (from 1.10 to 0.97 ppb) within the same period of time. Thus, the observed increase of the atmospheric benzene/toluene-mixing ratios from 0.32 to 0.58 (mean) is in good agreement with the predicted values from the presented emission model. Reduced catalyst conversion efficiency for benzene with respect to alkylated benzenes can explain most of the observed increase of the benzene/toluene and benzene/C{sub 2}-benzenes mixing rations. In addition, benzene emissions e.g. from the class of light duty vehicles, which

  9. Discussion of risks of platinum resources based on a function orientated criticality assessment. Shown by cytostatic drugs and automotive catalytic converters; Diskussion der Risiken der Ressource Platin auf Basis eines um funktionale Faktoren erweiterten Kritikalitaetsassessments. Dargestellt am Beispiel platinhaltiger Zytostatika und Autoabgaskatalysatoren

    Energy Technology Data Exchange (ETDEWEB)

    Thorenz, Andrea; Reller, Armin [University of Augsburg, Chair of Resource Strategy, Environment Science Center, Augsburg (Germany)

    2011-12-15

    The purpose of the study is the enhancement of criticality assessments for resources in order to address function specific factors like dissipation, recycling, bio-activity and toxicity. The developed methodology is applied to platinum-containing cytostatic drugs and automotive catalytic converters. Methods: The study is methodically based on an analysis of resource specific factors like exploration rates, reserves-to-production ratio and regional distribution of exploration areas as well as on the investigation of product/functional depending factors like recycling rates, dissipation rates, bio-diversity and toxicity. Taking into account that economic and ecological risks may occur at any stage of the supply, consumption and dissipation processes, the whole life cycles of the two analyzed products (cytostatic drugs and automotive catalytic converters) are considered. As an approach to reduce potential economic and ecological risks the study is especially focused on recycling strategies. In order to get a better understanding of platinum as an essential resource for the development of our society the history and the cultural impact of the term ''resource'' are introduced. The availability of platinum is crucial for several products of our modern society. Areas of application are e.g. jewellery, automotive catalytic converters, investments (coins, bars), computers, mobile devices, fertilizers and cytostatic drugs. Economic risks are caused by limited sources and dynamic demand of new application areas like fuel cells and drugs. Platinum-containing drugs are used for the treatment of several kinds of cancer such as testicular, breast, colon and prostate. Currently the pharmaceutical industry requires 6,9 tons per year (3 percent of the total demand of platinum). Due to the improvement of medical standards and the ageing society, especially in developing countries, the demand of platinum-containing drugs will rise significantly. The dissipation of

  10. Wavelength Converters

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Wolfson, David;

    1999-01-01

    at 2.5 Gbit/s, the regeneration causes a reduction of the required input power to an in-line EDFA of ~6 dB for a power penalty of 1 dB at a bit error rate of 10-9. If two converters are concatenated the power requirement is reduced ~8 dB. Obviously, the power reduction allows for longer spans between....... It is predicted that jitter accumulation can be minimised by using a 9-10 dB ratio between the signal and CW power also assuring a high extinction ratio. Using this guideline simulations show that 20 cross-gain modulation converters can be cascaded at 10 Gbit/s with only ~20 ps of accumulated jitter...... and an extinction ratio of ~10 dB.The regenerative capabilities of the cross-phase converters are described and verified experimentally at 20 Gbit/s, where the noise redistribution and improvement of the signal-to-noise ratio clearly is demonstrated by controlling the input power to an EDFA. In a similar experiment...

  11. Session 6: Effect of SO{sub 2} upon the reduction of No with C{sub 3}H{sub 8} using a fresh commercial Pt-Pd-Rh three-way catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Teran, M.E.; Martinez-Hernandez, A.; Rodriguez-Hernandez, F.; Fuentes, G.A. [Area de Ing. Quimica, Universidad A. Metropolitana-Iztapalapa, A.P., D. F (Mexico)

    2004-07-01

    In this work we studied the effect of SO{sub 2} upon the activity for oxidation of C{sub 3}H{sub 8} and NO reduction under stoichiometric conditions using a commercial Pt-Pd-Rh TWCC, a generic converter, employed to replace factory-installed TWCC that fail the statutory twice-yearly evaluation in Mexico City. There is hardly any information regarding the sensitivity of generic converters towards sulfur in gasoline, and that clearly is an issue when establishing city or nationwide plans to reformulate gasoline. (authors)

  12. Catalytic reaction in confined flow channel

    Energy Technology Data Exchange (ETDEWEB)

    Van Hassel, Bart A.

    2016-03-29

    A chemical reactor comprises a flow channel, a source, and a destination. The flow channel is configured to house at least one catalytic reaction converting at least a portion of a first nanofluid entering the channel into a second nanofluid exiting the channel. The flow channel includes at least one turbulating flow channel element disposed axially along at least a portion of the flow channel. A plurality of catalytic nanoparticles is dispersed in the first nanofluid and configured to catalytically react the at least one first chemical reactant into the at least one second chemical reaction product in the flow channel.

  13. 三元催化转化器转化效率影响因素分析%Influencing Factors Analysis of Conversion Efficiency of Three-way Catalytic Converter

    Institute of Scientific and Technical Information of China (English)

    孔祥华; 张海东

    2011-01-01

    针对三元催化转化器的起燃特性,建立转化器的数学模型.给出数值求解方法,讨论了在起燃阶段,进气性质、氢气、孔密度和空速等因素对转化效率的影响.结果表明,增加进气温度,增大孔密度,可缩短起燃时间,提高转化率;适当增大空速有利于提高转化率.%According to the light-off behavior of three-way catalyst, the mathematical model has been developed. Mathematical model was solved by finite difference. It was discussed that inlet gas property, hydrogen, cell density and space velocity can affect the converter efficiency in the light-off period. The results show that light-off time can be reduced by increasing inlet gas temperature and cell density. Conversion efficiency also can be improved by increasing space velocity.

  14. 排气质量流量和过量空气系数对三效催化转换器动态特性的影响%Effect of Exhaust Mass Flow and Inlet Excess Air Ratio on Dynamic Characteristic of Three-Way Catalytic Converter

    Institute of Scientific and Technical Information of China (English)

    何玲; 于秀敏; 李国良; 李想; 杜婷婷; 许艳军

    2011-01-01

    在发动机瞬态工况下,试验研究了排气质量流量、过量空气系数的阶跃幅值和周期对三效催化转换器动态特性的影响规律.试验结果表明,排气质量流量、过量空气系数的阶跃幅值和周期对三效催化转换器活性层中铈(Ce)表面氧气吸附和脱附存储能力(OSC)、排放影响显著.稀混合气向浓混合气阶跃后,排气质量流量增加,出口过量空气系数在理论混合气的时间并不线性增加,三效催化转换器出口排放降低,排气流量增加到一定值时,排放性能恶化.由浓混合气向稀混合气阶跃后,催化转换器出口的过量空气系数在理论混合气的时间随排气质量流量、过量空气系数的幅值线性增加.老化三效催化转换器的氧存储力减弱,是车载自动诊断系统(OBD)检测催化转换器是否老化的依据.%Dynamic response of three-way catalytic converter with different exhaust mass flows, inlet amplitude and period was analyzed experimentally under transient conditions. Results show that engine emissions and oxygen storage capacity (OSC)of three-way catalytic converter with Ceria (Ce)catalyst on the washcoat is affected by exhaust mass flow, amplitude and period of inlet excess air ratio. When ex- haust mass flow increases, emissions decrease at the beginning and turn deteriorated at some mass flow, and duration of outlet excess air ratio at stoichiometry increases non-linearly after the lean-rich step. Dura- tion of outlet excess air ratio at stoichiometry increases linearly as increasing exhaust mass flow and outlet excess air ratio amplitude after the rich-lean step. Oxygen storage capacity of Ceria of aged three-way cata- lytic converter is low and the on-board diagnostics (OBD) can diagnose the condition of three-way cata- lytic converter.

  15. Catalytic activities of platinum nanotubes: a density functional study

    Science.gov (United States)

    Mukherjee, Prajna; Gupta, Bikash C.; Jena, Puru

    2015-10-01

    In this work we investigate the catalytic properties of platinum nanotubes using density functional theory based calculations. In particular, we study the dissociation of hydrogen and oxygen molecules as well as oxidation of CO molecules. The results indicate that platinum nanotubes have good catalytic properties and can be effectively used in converting CO molecule to CO2.

  16. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  17. 三元催化器冷起动排放的数值模拟:数学模型与结果分析%Numerical Simulation of Cold-Start Emission for the Three-Way Catalytic Converter:Mathematical Model and Result Analysis

    Institute of Scientific and Technical Information of China (English)

    吴国江; 黄震; 陈晓玲

    2004-01-01

    This paper integrated a two-dimensional axisymmetrical transient model applicable to cold-start emission applications.The model can be used to simulate and explain effects of the flow and temperature distribution on performance of a converter.The evolutions of distribution of the temperature and concentration in the monolith during the cold-start period and the effects of flow distribution in the monolith on the cold-start performance are simulated in terms of the integrated model.The investigation indicates that the axial and radial gradients of temperature of the solid become steeper as the inlet gas temperature ramp increases; this furthermore results in the movement of reaction region in the monolith,and the flow distribution in the monolith affects the radial distribution of temperature of the solid;the radial gradients of temperature of the solid become greater as the flow uniformity index decreases,whereas the light-off time doesn't always increase as the flow uniformity index decreases.The analyses on the distribution of temperature and concentration in the monolith show that the catalytic reaction zone concentrates in central area near the front face.The predicted curves of the velocity distribution have a good agreement with the experimental data.

  18. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on air-optical wavelength converter types based on semiconductor optical amplifiers....

  19. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov;

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  20. Molecular catalytic coal liquid conversion

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.; Yang, Shiyong [Univ. of Chicago, IL (United States)

    1995-12-31

    This research, which is relevant to the development of new catalytic systems for the improvement of the quality of coal liquids by the addition of dihydrogen, is divided into two tasks. Task 1 centers on the activation of dihydrogen by molecular basic reagents such as hydroxide ion to convert it into a reactive adduct (OH{center_dot}H{sub 2}){sup {minus}} that can reduce organic molecules. Such species should be robust withstanding severe conditions and chemical poisons. Task 2 is focused on an entirely different approach that exploits molecular catalysts, derived from organometallic compounds that are capable of reducing monocyclic aromatic compounds under very mild conditions. Accomplishments and conclusions are discussed.

  1. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  2. Investigation into the Possibilities of Functioning Catalytic Converter

    OpenAIRE

    Saugirdas Pukalskas; Virginijus Švelnia; Ričardas Vėgneris

    2012-01-01

    The paper considers the principles of catalyst operations and chemical reactions proceeding within. Also, the modes used for defining the efficiency of the catalyst are reviewed. Experimental investigation has been carried out to help with assessing the efficacy of the catalyst according to the concentration of noxious fractions and differences in temperature before and behind the catalyst. Nine Otto engine vehicles have been tested. The applicable contamination level and efficiency of cataly...

  3. Investigation into the Possibilities of Functioning Catalytic Converter

    Directory of Open Access Journals (Sweden)

    Saugirdas Pukalskas

    2012-11-01

    Full Text Available The paper considers the principles of catalyst operations and chemical reactions proceeding within. Also, the modes used for defining the efficiency of the catalyst are reviewed. Experimental investigation has been carried out to help with assessing the efficacy of the catalyst according to the concentration of noxious fractions and differences in temperature before and behind the catalyst. Nine Otto engine vehicles have been tested. The applicable contamination level and efficiency of catalyst performance of the vehicles have been set. The conclusion reveals that flowing gas temperature within the vehicle having an effectively performing catalyst is always lower than out flowing gas temperature.

  4. Control Oriented Modeling of the Dynamics in a Catalytic Converter

    OpenAIRE

    Johansson, Jenny; Waller, Mikaela

    2005-01-01

    Avgasmängden som bensindrivna fordon tillåts släppa ut minskas hela tiden. Ett sätt att möta framtida krav, är att förbättra katalysatorns effektivitet. För att göra detta kan luft-bränsle-förhållandet regleras med avseende på syrelagringen i katalysatorn, istället för som idag, reglera mot stökiometriskt blandningsförhållande. Eftersom syrelagringen inte går att mäta med en givare behövs en modell som beskriver katalysatorns dynamiska egenskaper. Tre sådana modeller har undersökts, utvärdera...

  5. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-09-06

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  6. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-03-08

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  7. Low efficiency deasphalting and catalytic cracking

    International Nuclear Information System (INIS)

    This patent describes a process for converting an asphaltene and metals containing heavy hydrocarbon feed to lighter, more valuable products the metals comprising Ni and V. It comprises: demetallizing the feed by deasphalting the feed in a solvent deasphalting means operating at solvent deasphalting conditions including a solvent: feed volume ratio of about 1:1 to 4:1, using a solvent selected from the group of C4 to 400 degrees F. hydrocarbons and mixtures thereof; recovering from the solvent rich fraction a demetallized oil intermediate product, having a boiling range and containing at least 10 wt.% of the asphaltenes, and 5 to 30% of the Ni and V, and at least 10 wt.% of the solvent present in the solvent rich phase produced in the deasphalting means; catalytically cracking the demetallized oil intermediate product in a catalytic cracking means operating at catalytic cracking conditions to produce a catalytically cracked product vapor fraction having a lower boiling range than the boiling range of the demetallized oil intermediate product; and fractionating the catalytically cracked product in a fractionation means to produce catalytically cracked product fractions

  8. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; Boom, van den Jeroen M.; Dijkmans, Eise C.

    2002-01-01

    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is off

  9. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; Boom, van den Jeroen M.; Dijkmans, Eise C.

    2006-01-01

    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is off

  10. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  11. SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Frigaard, Peter

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A key to success for the SSG will be the low cost of the structure and its robustness. The construction of the pilot plant is scheduled and this paper aims to describe the concept of the SSG wave energy converter...

  12. Converting Nonclassicality into Entanglement.

    Science.gov (United States)

    Killoran, N; Steinhoff, F E S; Plenio, M B

    2016-02-26

    Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting nonclassicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are "symmetric coherent states," connected with symmetric representations of the group SU(K). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and nonlocal pictures of nonclassicality. PMID:26967398

  13. Converting Nonclassicality into Entanglement.

    Science.gov (United States)

    Killoran, N; Steinhoff, F E S; Plenio, M B

    2016-02-26

    Quantum mechanics exhibits a wide range of nonclassical features, of which entanglement in multipartite systems takes a central place. In several specific settings, it is well known that nonclassicality (e.g., squeezing, spin squeezing, coherence) can be converted into entanglement. In this work, we present a general framework, based on superposition, for structurally connecting and converting nonclassicality to entanglement. In addition to capturing the previously known results, this framework also allows us to uncover new entanglement convertibility theorems in two broad scenarios, one which is discrete and one which is continuous. In the discrete setting, the classical states can be any finite linearly independent set. For the continuous setting, the pertinent classical states are "symmetric coherent states," connected with symmetric representations of the group SU(K). These results generalize and link convertibility properties from the resource theory of coherence, spin coherent states, and optical coherent states, while also revealing important connections between local and nonlocal pictures of nonclassicality.

  14. Thermionic photovoltaic energy converter

    Science.gov (United States)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  15. Catalytic Decomposition of Methylene Chloride by Sulfated Titania Catalysts

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Catalytic decomposition of methylene chloride in air below 300℃ was studied.Sulfated titania was very effective in converting 959ppm methylene chloride selectively to CO,CO2 and HCl.Complete decomposition of methylene chloride was achieved at low temperature(275℃).It was found that the acidic property of catalyst was a determinant factor for the catalytic activity.The presence of water vapor in the feed stream remarkably reduced the catalytic activity,which could be due to the blockage of acidic sites on the surface of catalyst by water molecules.A bifunctional catalyst comprising copper oxide was developed to improve the selectivity of catalytic oxidation,which indicated that copper oxide can promote the deep oxidation of methylene chloride.The crystal form of TiO2 imposes an important influence upon the catalytic oxidation.

  16. Novel Catalytic Reactor for CO2 Reduction via Sabatier Process Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop a novel, efficient, and lightweight catalytic Sabatier CO2 methanation unit, capable of converting a mixture of...

  17. Catalytic conversion of light alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J.E.

    1992-06-30

    The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).

  18. Improving Power Converter Reliability

    DEFF Research Database (Denmark)

    Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon;

    2014-01-01

    The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental...... cycle of the current by calibrating them at load current. The measurement is very accurate and also measures the voltage at the middle of a pulse-width modulation (PWM) switching. A major objective is that this method is designed to be implemented in real applications. The performance of this technique...

  19. Angiotensin-converting enzyme

    DEFF Research Database (Denmark)

    Sørensen, P G; Rømer, F K; Cortes, D

    1984-01-01

    In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical or radiolog......In order to evaluate bleomycin-associated lung damage in humans, lung function parameters and serum levels of the endothelial-bound angiotensin-converting enzyme (ACE) were determined by serial measurements in 11 patients who were treated for testicular cancer. None developed clinical...

  20. Catalytic distillation structure

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1984-01-01

    Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

  1. Catalytic combustor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mercea, J.; Grecu, E.; Fodor, T.; Kreibik, S.

    1982-01-01

    The performance of catalytic combustors for hydrogen using platinum-supported catalysts is described. Catalytic plates of different sizes were constructed using fibrous and ceramic supports. The temperature distribution as well as the reaction efficiency as a function of the fuel input rate was determined, and a comparison between the performances of different plates is discussed.

  2. The Convertible Arbitrage Strategy Analyzed

    NARCIS (Netherlands)

    Loncarski, I.; Ter Horst, J.R.; Veld, C.H.

    2006-01-01

    This paper analyzes convertible bond arbitrage on the Canadian market for the period 1998 to 2004.Convertible bond arbitrage is the combination of a long position in convertible bonds and a short position in the underlying stocks. Convertible arbitrage has been one of the most successful strategies

  3. Convertible Proxy Signcryption Scheme

    Institute of Scientific and Technical Information of China (English)

    李继国; 李建中; 曹珍富; 张亦辰

    2004-01-01

    In 1996, Mambo et al introduced the concept of proxy signature. However, proxy signature can only provide the delegated authenticity and cannot provide confidentiality. Recently, Gamage et al and Chan and Wei proposed different proxy signcryption schemes respectively, which extended the concept of proxy signature.However, only the specified receiver can decrypt and verify the validity of proxy signcryption in their schemes.To protect the receiver' s benefit in case of a later dispute, Wu and Hsu proposed a convertible authenticated encryption scheme, which carn enable the receiver to convert signature into an ordinary one that can be verified by anyone. Based on Wu and Hsu' s scheme and improved Kim' s scheme, we propose a convertible proxy signcryption scheme. The security of the proposed scheme is based on the intractability of reversing the one-way hash function and solving the discrete logarithm problem. The proposed scheme can satisfy all properties of strong proxy signature and withstand the public key substitution attack and does not use secure channel. In addition, the proposed scheme can be extended to convertible threshold proxy signcryption scheme.

  4. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  5. Definition of Power Converters

    CERN Document Server

    Bordry, F

    2015-01-01

    The paper is intended to introduce power conversion principles and to define common terms in the domain. The concept s of sources and switches are defined and classified. From the basic laws of source interconnections, a generic method of power converter synthesis is presented. Some examples illustrate this systematic method. Finally, the commutation cell and soft commuta tion are introduced and discussedd.

  6. Fractional Watt AMTEC Converter

    Science.gov (United States)

    Hunt, T. K.; Rasmussen, J. R.

    2006-01-01

    We report here the long term performance of a small, multi-tube AMTEC converter. This converter was designed to operate and produce approximately 12 watt of electrical output from a small, 4 to 6 watt radioisotope heat source for remote power applications. It was built and put on test in 1999 using electrical heaters as stand-ins for the radioisotope capsule. Since that time it has accumulated more than 5 years of run time at an input heater temperature of 700 °C, with numerous thermal cycles to ambient that were generally related to grid power failures or physical moves of the test apparatus. The power output has remained, with variations due to orientation changes and minor variations due to small temperature changes, essentially constant at 0.40 W to 0.60 W over the test period and operation is ongoing. The converter casing and mechanical structure was fabricated from 316 SS and the electrodes are sputtered titanium nitride films. Separate static tests of a multilayer insulation package suitable for use with the converter showed the capability to reach 700 °C with a thermal input of < 4 watts.

  7. Advanced DC/DC converters

    CERN Document Server

    Luo, Fang Lin

    2003-01-01

    INTRODUCTIONHistorical ReviewMultiple Quadrant ChoppersPump CircuitsDevelopment of DC/DC Conversion TechniqueCategorize Prototypes and DC/DC Converters Family TreeVOLTAGE-LIFT CONVERTERSIntroductionSeven Self-Lift ConvertersPositive Output Luo-ConvertersNegative Output Luo-ConvertersModified Positive Output Luo-Converters Double Output Luo-ConvertersPOSITIVE OUTPUT SUPER-LIFT LUO-CONVERTERS IntroductionMain SeriesAdditional SeriesEnhanced Series Re-Enhanced Series Multiple-Enhanced Series Summary of Positive Output

  8. Ex-Situ Catalytic Fast Pyrolysis Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, M.; Dutta, A.; Jones, S.; Meyer, A.

    2013-03-01

    This technology pathway case investigates converting woody biomass using ex-situ catalytic fast pyrolysis followed by upgrading to gasoline-, diesel-, and jet-range hydrocarbon blendstocks. Technical barriers and key research needs that should be pursued for this pathway to be competitive with petroleum-derived blendstocks have been identified.

  9. In-Situ Catalytic Fast Pyrolysis Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, M.; Dutta, A.; Jones, S.; Meyer, A.

    2013-03-01

    This technology pathway case investigates converting woody biomass using in-situ catalytic fast pyrolysis followed by upgrading to gasoline-, diesel-, and jet-range hydrocarbon blendstocks. Technical barriers and key research needs that should be pursued for this pathway to be competitive with petroleum-derived blendstocks have been identified.

  10. DSP controlled power converter

    OpenAIRE

    Chan, CH; Pong, MH

    1995-01-01

    A digital controller is designed and implemented by a Digital Signal Processor (DSP) to replace the Pulse Width Modulator (PWM) and error amplifier compensation network in a two wheeler forward converter. The DSP controller is designed in three approaches: a) Discretization of analog controller - the design is based on the transfer function of the error amplifier compensation network. b) Digital PID controller design - the design is based on the general form of the pulse transfer function of ...

  11. Convertible bond valuation focusing on Chinese convertible bond market

    OpenAIRE

    Yang, Ke

    2010-01-01

    This paper mainly discusses the methods of valuation of convertible bonds in Chinese market. Different from common convertible bonds in European market, considering the complicate features of Chinese convertible bond, this paper represents specific pricing approaches for pricing convertible bonds with different provisions along with the increment of complexity of these provisions. More specifically, this paper represents the decomposing method and binomial tree method for pricing both of Non-...

  12. Catalytic fast pyrolysis of lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Changjun; Wang, Huamin; Karim, Ayman M.; Sun, Junming; Wang, Yong

    2014-11-21

    Increasing energy demand, especially in the transportation sector, and soaring CO2 emissions necessitate the exploitation of renewable sources of energy. Despite the large variety of new energy Q3 carriers, liquid hydrocarbon still appears to be the most attractive and feasible form of transportation fuel taking into account the energy density, stability and existing infrastructure. Biomass is an abundant, renewable source of energy; however, utilizing it in a cost-effective way is still a substantial challenge. Lignocellulose is composed of three major biopolymers, namely cellulose, hemicellulose and lignin. Fast pyrolysis of biomass is recognized as an efficient and feasible process to selectively convert lignocellulose into a liquid fuel—bio-oil. However bio-oil from fast pyrolysis contains a large amount of oxygen, distributed in hundreds of oxygenates. These oxygenates are the cause of many negative properties, such as low heating values, high corrosiveness, high viscosity, and instability; they also greatly Q4 limit the application of bio-oil particularly as transportation fuel. Hydrocarbons derived from biomass are most attractive because of their high energy density and compatibility with the existing infrastructure. Thus, converting lignocellulose into transportation fuels via catalytic fast pyrolysis has attracted much attention. Many studies related to catalytic fast pyrolysis of biomass have been published. The main challenge of this process is the development of active and stable catalysts that can deal with a large variety of decomposition intermediates from lignocellulose. This review starts with the current understanding of the chemistry in fast pyrolysis of lignocellulose and focuses on the development of catalysts in catalytic fast pyrolysis. Recent progress in the experimental studies on catalytic fast pyrolysis of biomass is also summarized with the emphasis on bio-oil yields and quality.

  13. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  14. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the diffusi

  15. Catalytic ignition of light hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    K. L. Hohn; C.-C. Huang; C. Cao

    2009-01-01

    Catalytic ignition refers to phenomenon where sufficient energy is released from a catalytic reaction to maintain further reaction without additional extemai heating. This phenomenon is important in the development of catalytic combustion and catalytic partial oxidation processes, both of which have received extensive attention in recent years. In addition, catalytic ignition studies provide experimental data which can be used to test theoretical hydrocarbon oxidation models. For these reasons, catalytic ignition has been frequently studied. This review summarizes the experimental methods used to study catalytic ignition of light hydrocarbons and describes the experimental and theoretical results obtained related to catalytic ignition. The role of catalyst metal, fuel and fuel concentration, and catalyst state in catalytic ignition are examined, and some conclusions are drawn on the mechanism of catalytic ignition.

  16. Resonant power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2012-01-01

    This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

  17. Cycloidal Wave Energy Converter

    Energy Technology Data Exchange (ETDEWEB)

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  18. SIGN LANGUAGE CONVERTER

    Directory of Open Access Journals (Sweden)

    Taner Arsan

    2015-08-01

    Full Text Available The aim of this paper is to design a convenient system that is helpful for the people who have hearing difficulties and in general who use very simple and effective method; sign language. This system can be used for converting sign language to voice and also voice to sign language. A motion capture system is used for sign language conversion and a voice recognition system for voice conversion. It captures the signs and dictates on the screen as writing. It also captures the voice and displays the sign language meaning on the screen as motioned image or video.

  19. SIGN LANGUAGE CONVERTER

    OpenAIRE

    Taner Arsan; Oğuz Ülgen

    2015-01-01

    The aim of this paper is to design a convenient system that is helpful for the people who have hearing difficulties and in general who use very simple and effective method; sign language. This system can be used for converting sign language to voice and also voice to sign language. A motion capture system is used for sign language conversion and a voice recognition system for voice conversion. It captures the signs and dictates on the screen as writing. It also captures the voice ...

  20. Catalytic coherence transformations

    Science.gov (United States)

    Bu, Kaifeng; Singh, Uttam; Wu, Junde

    2016-04-01

    Catalytic coherence transformations allow the otherwise impossible state transformations using only incoherent operations with the aid of an auxiliary system with finite coherence that is not being consumed in any way. Here we find the necessary and sufficient conditions for the deterministic and stochastic catalytic coherence transformations between a pair of pure quantum states. In particular, we show that the simultaneous decrease of a family of Rényi entropies of the diagonal parts of the states under consideration is a necessary and sufficient condition for the deterministic catalytic coherence transformations. Similarly, for stochastic catalytic coherence transformations we find the necessary and sufficient conditions for achieving a higher optimal probability of conversion. We thus completely characterize the coherence transformations among pure quantum states under incoherent operations. We give numerous examples to elaborate our results. We also explore the possibility of the same system acting as a catalyst for itself and find that indeed self-catalysis is possible. Further, for the cases where no catalytic coherence transformation is possible we provide entanglement-assisted coherence transformations and find the necessary and sufficient conditions for such transformations.

  1. Unity power factor converter

    Science.gov (United States)

    Wester, Gene W. (Inventor)

    1980-01-01

    A unity power factor converter capable of effecting either inversion (dc-to-dc) or rectification (ac-to-dc), and capable of providing bilateral power control from a DC source (or load) through an AC transmission line to a DC load (or source) for power flow in either direction, is comprised of comparators for comparing the AC current i with an AC signal i.sub.ref (or its phase inversion) derived from the AC ports to generate control signals to operate a switch control circuit for high speed switching to shape the AC current waveform to a sine waveform, and synchronize it in phase and frequency with the AC voltage at the AC ports, by selectively switching the connections to a series inductor as required to increase or decrease the current i.

  2. An Experimental Study of Flow and Thermal Transient Response in a Race-Track Monolith Catalytic Converter Etude expérimentale de l'écoulement et de la réponse thermique en régime transitoire dans un pot catalytique muni d'un monolithe de forme ovale

    Directory of Open Access Journals (Sweden)

    Leclerc J. P.

    2006-11-01

    Full Text Available A model for the pressure drop was proposed and compared to experimental results. Global flow characteristics and velocity distribution were studied from residence time distribution measurements in a race-trackmonolith. Significant dead volumes were detected and the velocity distribution was determined. The effect of flow-rate, inlet tube diameter and flow deflector was investigated. Study of the time evolution of outlet temperature and temperature distribution in a monolith coated or not with catalyst makes it possible to determine the thermal characteristics of heat-up. The influence of flow rate, velocity distribution and developing laminar flow regime in the channel were qualitatively estimated. Theses results allow one to determine the hydrodynamic and thermal behavior of the catalytic converter and to propose reliable and realistic assumptions for subsequent modeling. Chaque année, un véhicule de moyenne cylindrée rejette dans l'atmosphère 240 kg de monoxyde de carbone, 40 kg d'oxyde d'azote et 77 kg d'hydrocarbures [1]. Si le moteur propre semble être la meilleure solution pour l'avenir, le pot catalytique est aujourd'hui la seule solution envisageable. Le fonctionnement du pot catalytique est satisfaisant lorsque la voiture roule à une vitesse constante. Cependant, il n'en est pas de même lors du démarrage à froid pendant lequel de nombreux problèmes subsistent, comme le montre la figure 1. Plusieurs modèles ont été développés afin de comprendre et d'améliorer les performances du pot catalytique [2, 3, 11, 12 et 13]. Cependant, suivant les hypothèses faites, ces modèles fournissent des résultats plus ou moins contradictoires. Une étude expérimentale a donc été effectuée afin de mieux cerner les processus qui gouvernent le fonctionnement du pot catalytique et de proposer des hypothèses réalistes pour la modélisation. Un modèle d'estimation de la perte de charge a été proposé et comparé aux résultats exp

  3. Integrated power electronic converters and digital control

    CERN Document Server

    Emadi, Ali; Nie, Zhong

    2009-01-01

    Non-isolated DC-DC ConvertersBuck ConverterBoost ConverterBuck-Boost ConverterIsolated DC-DC ConvertersFlyback ConverterForward ConverterPush-Pull ConverterFull-Bridge ConverterHalf-Bridge ConverterPower Factor CorrectionConcept of PFCGeneral Classification of PFC CircuitsHigh Switching Frequency Topologies for PFCApplication of PFC in Advanced Motor DrivesIntegrated Switched-Mode Power ConvertersSwitched-Mode Power SuppliesThe Concept of Integrated ConverterDefinition of Integrated Switched-Mode Power Supplies (ISMPS)Boost-Type Integrated TopologiesGeneral Structure of Boost-Type Integrated T

  4. Advanced power electronics converters PWM converters processing AC voltages

    CERN Document Server

    dos Santos, Euzeli

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, which can be used both as a textbook and reference book.  Introduces a new method to present power electronics converters called Power Blocks Geometry. Applicable for courses focusing on power electronics, power electronics converters, and advanced power converters. Offers a comprehensive set of simulation results to help understand the circuits presented throughout the book

  5. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  6. Nanostructure Neutron Converter Layer Development

    Science.gov (United States)

    Park, Cheol (Inventor); Sauti, Godfrey (Inventor); Kang, Jin Ho (Inventor); Lowther, Sharon E. (Inventor); Thibeault, Sheila A. (Inventor); Bryant, Robert G. (Inventor)

    2016-01-01

    Methods for making a neutron converter layer are provided. The various embodiment methods enable the formation of a single layer neutron converter material. The single layer neutron converter material formed according to the various embodiments may have a high neutron absorption cross section, tailored resistivity providing a good electric field penetration with submicron particles, and a high secondary electron emission coefficient. In an embodiment method a neutron converter layer may be formed by sequential supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In another embodiment method a neutron converter layer may be formed by simultaneous supercritical fluid metallization of a porous nanostructure aerogel or polyimide film. In a further embodiment method a neutron converter layer may be formed by in-situ metalized aerogel nanostructure development.

  7. Catalytic Conversion of Biofuels

    DEFF Research Database (Denmark)

    Jørgensen, Betina

    This thesis describes the catalytic conversion of bioethanol into higher value chemicals. The motivation has been the unavoidable coming depletion of the fossil resources. The thesis is focused on two ways of utilising ethanol; the steam reforming of ethanol to form hydrogen and the partial oxida...

  8. Catalytic Phosphination and Arsination

    Institute of Scientific and Technical Information of China (English)

    Kwong Fuk Yee; Chan Kin Shing

    2004-01-01

    The catalytic, user-friendly phosphination and arsination of aryl halides and triflates by triphenylphosphine and triphenylarsine using palladium catalysts have provided a facile synthesis of functionalized aryl phosphines and arsines in neutral media. Modification of the cynaoarisne yielded optically active N, As ligands which will be screened in various asymmetric catalysis.

  9. Catalytic efficiency of designed catalytic proteins.

    Science.gov (United States)

    Korendovych, Ivan V; DeGrado, William F

    2014-08-01

    The de novo design of catalysts that mimic the affinity and specificity of natural enzymes remains one of the Holy Grails of chemistry. Despite decades of concerted effort we are still unable to design catalysts as efficient as enzymes. Here we critically evaluate approaches to (re)design of novel catalytic function in proteins using two test cases: Kemp elimination and ester hydrolysis. We show that the degree of success thus far has been modest when the rate enhancements seen for the designed proteins are compared with the rate enhancements by small molecule catalysts in solvents with properties similar to the active site. Nevertheless, there are reasons for optimism: the design methods are ever improving and the resulting catalyst can be efficiently improved using directed evolution.

  10. Venturini Method Based Matrix Converter

    Directory of Open Access Journals (Sweden)

    Derick Mathew

    2015-03-01

    Full Text Available Recently, matrix converter has received considerable interest as a viable alternative to the conventional ac-dc-ac converter. This direct ac-ac converter provides some attractive characteristics such as: four quadrant operation, absence of bulky dc-link electrolyte capacitors, clean input power characteristics. Due to the absence of dc link energy storage elements any disturbance in the input voltage will be immediately reflected to the output voltages. In this paper venturini method for matrix converter has been presented. Three phase sinusoidal symmetrical voltage or current can obtained .

  11. A thermochemical energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Toyeguti, K.; Indzima, T.

    1982-08-09

    Mercury is used as the active mass of the anode in the converter and 0/sub 2/ is used as the active cathode material. The reaction of Mercury + 1/2 0/sub 2/-Hg0 occurs with a discharge. With heating to 500/sup 0/C the regeneration of the Mercury, Hg0 yields Mercury + 1/2 0/sub 2/, occurs. The device for performing the thermochenical conversion of energy contains an element body, an oxygen chamber, an oxygen electrode, a chamber with an alkaline liquid electrolyte, a separator, an auxiliary separator, an electrode and a chamber with the Mercury. The thermochemical reaction occurs in the reactor to which the Hg0 is transported along a pipe which has a refrigerator and a valve. The Mercury is fed into the element from a reservoir. The Mercury reduced in the reactor and in a reaction tower is fed into it through a closed cycle. The bellows is connected with the reactor by a pipe with a refrigerator. Through it the 0/sub 2/ goes in a closed cycle to the chamber. The current forming reactions are Hg + 20H-anion yields Hg0 + H/sub 2/0 + 2e and 1/2 0/sub 2/ + H/sub 2/0 + 2e yields 20H-anion. The voltage on the outleads of the element is approximately 0.3 volts.

  12. Les procédés ASVAHL thermiques et catalytiques sous pression d'hydrogène pour la conversion des bruts lourds et des résidus de bruts classiques Thermal and Catalytic Asvahl Processes under Hydrogen Pressure for Converting Heavy Crudes and Conventional Residues

    Directory of Open Access Journals (Sweden)

    Peries J. P.

    2006-11-01

    Full Text Available Cet article décrit les performances comparées des procédés ASVAHL thermiques (TERVAHL T, TERVAHL H, TERVAHL HC et catalytiques (HYVAHL F, HYVAHL C dans deux cas de traitement: - brut désessencié Boscan (base des études objectif Transport; - résidu sous vide Safaniya (base des études Raffinage de résidu. A travers ces résultats, l'importance de la quantité d'hydrogène fixée est mise en évidence. Elle joue sur la conversion obtenue et sur la qualité des résidus. L'introduction de catalyseur soluble ou en suspension catalytique TERVAHL HC (hydroviscoréduction catalytique ou l'utilisation d'un catalyseur supporté (hydrotraiternent HYVAHL favorisent l'activation de l'hydrogène. C'est la combinaison des réactions de craquage, de polycondensation et d'hydrogénation, et les conditions opératoires (températures, temps de séjour et pression qui définiront les limites de la conversion pour une stabilité donnée des résidus. This article describes the comparative performances of thermal ASVAHL processes (TERVAHL T, TERVAHL H, TERVAHL HQ and catalytic ASVAHL processes (HYVAHL F, HYVAHL C for two types of processing: (1 degasolined Boscan crude (basis of studies for transportation feasibility, and (2 Safaniya vacuum residue (basis of studies for residue refining. The results reveal the importance of the amount of fixed hydrogen, which affects the conversion obtained and the quality of the residues. The introduction of a TERVAHL HC soluble catalyst or one in catalytic suspension (catalytic hydrovisbreaking or the use of a supported catalyst (HYVAHL hydrotreatment enhances the activation of hydrogen. The combination of cracking, polycondensation and hydrogen reactions together with the operating conditions (temperatures, residence time and pressure are what will define the conversion limits for a given stability of residues.

  13. Inactivation of human angiotensin converting enzyme by copper peptide complexes containing ATCUN motifs.

    Science.gov (United States)

    Gokhale, Nikhil H; Cowan, J A

    2005-12-21

    The copper complex [KGHK-Cu]+ demonstrates catalytic inactivation of human angiotensin converting enzyme at sub-saturating concentrations, under oxidative conditions, with an observed rate constant k approximately 2.9 +/- 0.5 x 10(-2) min(-1). PMID:16317474

  14. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  15. Roles of catalytic oxidation in control of vehicle exhaust emissions

    International Nuclear Information System (INIS)

    Catalytic oxidation was initially associated with the early development of catalysis and it subsequently became a part of many industrial processes, so it is not surprising it was used to remove hydrocarbons and CO when it became necessary to control these emissions from cars. Later NOx was reduced in a process involving reduction over a Pt/Rh catalyst followed by air injection in front of a Pt-based oxidation catalyst. If over-reduction of NO to NH3 took place, or if H2S was produced, it was important these undesirable species were converted to NOx and SOx in the catalytic oxidation stage. When exhaust gas composition could be kept stoichiometric hydrocarbons, CO and NOx were simultaneously converted over a single Pt/Rh three-way catalyst (TWC). With modern TWCs car tailpipe emissions can be exceptionally low. NO is not catalytically dissociated to O2 and N2 in the presence of O2, it can only be reduced to N2. Its control from lean-burn gasoline engines involves catalytic oxidation to NO2 and thence nitrate that is stored and periodically reduced to N2 by exhaust gas enrichment. This method is being modified for diesel engines. These engines produce soot, and filtration is being introduced to remove it. The exhaust temperature of heavy-duty diesels is sufficient (250-400oC) for NO to be catalytically oxidised to NO2 over an upstream platinum catalyst that smoothly oxidises soot in the filter. The exhaust gas temperature of passenger car diesels is too low for this to take place all of the time, so trapped soot is periodically burnt in O2 above 550oC. Catalytic oxidation of higher than normal amounts of hydrocarbon and CO over an upstream catalyst is used to give sufficient temperature for soot combustion with O2 to take place. (author)

  16. A catalytic cracking process

    Energy Technology Data Exchange (ETDEWEB)

    Degnan, T.F.; Helton, T.E.

    1995-07-20

    Heavy oils are subjected to catalytic cracking in the absence of added hydrogen using a catalyst containing a zeolite having the structure of ZSM-12 and a large-pore crystalline zeolite having a Constraint Index less than about 1. The process is able to effect a bulk conversion of the oil at the same time yielding a higher octane gasoline and increased light olefin content. (author)

  17. Radiation tolerant power converter controls

    CERN Document Server

    Todd, B; King, Q; Uznanski, S

    2012-01-01

    The Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN) is the world's most powerful particle collider. The LHC has several thousand magnets, both warm and super-conducting, which are supplied with current by power converters. Each converter is controlled by a purpose-built electronic module called a Function Generator Controller (FGC). The FGC allows remote control of the power converter and forms the central part of a closed-loop control system where the power converter voltage is set, based on the converter output current and magnet-circuit characteristics. Some power converters and FGCs are located in areas which are exposed to beam-induced radiation. There are numerous radiation induced effects, some of which lead to a loss of control of the power converter, having a direct impact upon the accelerator's availability. Following the first long shut down (LS1), the LHC will be able to run with higher intensity beams and higher beam energy. This is expected to lead to signifi...

  18. PWM DC/DC Converter

    OpenAIRE

    Chen, Juan

    2008-01-01

    This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...

  19. Processes for converting lignocellulosics to reduced acid pyrolysis oil

    Science.gov (United States)

    Kocal, Joseph Anthony; Brandvold, Timothy A

    2015-01-06

    Processes for producing reduced acid lignocellulosic-derived pyrolysis oil are provided. In a process, lignocellulosic material is fed to a heating zone. A basic solid catalyst is delivered to the heating zone. The lignocellulosic material is pyrolyzed in the presence of the basic solid catalyst in the heating zone to create pyrolysis gases. The oxygen in the pyrolysis gases is catalytically converted to separable species in the heating zone. The pyrolysis gases are removed from the heating zone and are liquefied to form the reduced acid lignocellulosic-derived pyrolysis oil.

  20. Study on flow mode of combined converter for methanol synthesis from coal-based syngas

    Institute of Scientific and Technical Information of China (English)

    XIAO Zhen-ping; MA Hong-fang; YING Wei-yong; FANG Ding-ye

    2011-01-01

    The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established.The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that ifthe flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. Therefore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.

  1. Time-to-digital converters

    CERN Document Server

    Henzler, Stephan

    2010-01-01

    This text covers the fundamentals of time-to-digital converters on analog and digital conversion principles. It includes a theoretical investigation into quantization, linearity, noise and variability, and it details a range of advanced TDC architectures.

  2. Laser system with wavelength converter

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to an apparatus comprising a diode laser (10) providing radiation in a first wavelength interval, a radiation conversion unit (12) having an input and an output, the radiation converter configured to receive the radiation in the first wavelength interval from the diode...... laser at the input, the radiation conversion unit configured to convert the radiation in the first wavelength interval to radiation in a second wavelength interval and the output configured to output the converted radiation, the second wavelength interval having one end point outside the first...... wavelength interval. Further, the invention relates to a method of optically pumping a target laser (14) in a laser system, the laser system comprising a laser source providing radiation at a first frequency, the laser source being optically connected to an input of a frequency converter, the frequency...

  3. PHASE CONVERTER OF COMPOSING DISPLACEMENT

    OpenAIRE

    SMIRNOV YU.S.; Lysov, A. N.; E.V. Yurasova; SAFRONOV V.V.; VSTAVSKAYA E.V.

    2016-01-01

    Minimax strategy of mechatronic converters efficiency improving relative to error decrease with velocity increase at the same time provides common dataware level rise. The analysis of usage possibilities of different type position transducers (PT) gives the advantages of resolvers. The subsequent processing of their output signals is performed by “Resolver-to-Digit” Converter (RDC) which provides displacement digital equivalent and digital or analog signals specifying its velocity and acceler...

  4. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  5. Transformerless dc-Isolated Converter

    Science.gov (United States)

    Rippel, Wally E.

    1987-01-01

    Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.

  6. Dimethyl carbonate as potential reactant in non-catalytic biodiesel production by supercritical method

    OpenAIRE

    Ilham, Zul; Saka, Shiro

    2009-01-01

    In this study, the non-catalytic supercritical method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal. After 12 min of reaction at 350 °C/20 MPa, rapeseed oil treated with supercritical dimethyl carbona...

  7. Current status of converter steelmaking

    Energy Technology Data Exchange (ETDEWEB)

    Oghbasialasie, H.; Holappa, L.

    1995-12-31

    This literature work is mainly focusing on the mechanisms of modern converter steelmaking and related with the evaluation of converter technology applied during the last decades and further to the future. The history of steelmaking has been briefly reviewed from bloomeries and early-steelmaking processes to the progress of modern converter process. The pneumatic converter processes were developed in the 1850`s and thereafter the basis for the rapid growth of steel industries was established for the next 100 years. The world production of steel has not continuously grown but fluctuating quite much. It reached 723 Mt in 1994. The production is believed to grow the forecast for the year 2003 being approximately 800 Mt. Electric arc furnace production is estimated to reach 280 Mt by 2003, and BOFIOH will reach 520 Mt by 2003. The current status of the converter steelmaking process is briefly described both on its theoretical bases and practical technological progresses. Developments which significantly improve the process are briefly discussed. Several more recent developments such as combined oxygen blowing process, increased scrap melting, post combustion and hot metal pretreatment are discussed. The future progress will be in further development of these process characteristics as well as in eventual emerging of the continuous converter process. (author)

  8. Loss of collectrin, an angiotensin-converting enzyme 2 homolog, uncouples endothelial nitric oxide synthase and causes hypertension and vascular dysfunction

    DEFF Research Database (Denmark)

    Cechova, Sylvia; Zeng, Qing; Billaud, Marie;

    2013-01-01

    Collectrin is an orphan member of the renin-angiotensin system and is a homolog of angiotensin-converting enzyme 2, sharing ≈50% sequence identity. Unlike angiotensin-converting enzyme 2, collectrin lacks any catalytic domain. Collectrin has been shown to function as a chaperone of amino acid tra...

  9. Catalytic combustion in small wood burning appliances

    Energy Technology Data Exchange (ETDEWEB)

    Oravainen, H. [VTT Energy, Jyvaeskylae (Finland)

    1996-12-31

    There is over a million hand fired small heating appliances in Finland where about 5,4 million cubic meters of wood fuel is used. Combustion in such heating appliances is a batch-type process. In early stages of combustion when volatiles are burned, the formation of carbon monoxide (CO) and other combustible gases are difficult to avoid when using fuels that have high volatile matter content. Harmful emissions are formed mostly after each fuel adding but also during char burnout period. When the CO-content in flue gases is, say over 0.5 %, also other harmful emissions will be formed. Methane (CH{sub 4}) and other hydrocarbons are released and the amount of polycyclic aromatic hydrocarbons (PAH)-compounds can be remarkable. Some PAH-compounds are very carcinogenic. It has been estimated that in Finland even more than 90 % of hydrocarbon and PAH emissions are due to small scale wood combustion. Emissions from transportation is excluded from these figures. That is why wood combustion has a net effect on greenhouse gas phenomena. For example carbon monoxide emissions from small scale wood combustion are two fold compared to that of energy production in power plants. Methane emission is of the same order as emission from transportation and seven fold compared with those of energy production. Emissions from small heating appliances can be reduced by developing the combustion techniques, but also by using other means, for example catalytic converters. In certain stages of the batch combustion, temperature is not high enough, gas mixing is not good enough and residence time is too short for complete combustion. When placed to a suitable place inside a heating appliance, a catalytic converter can oxidize unburned gases in the flue gas into compounds that are not harmful to the environment. (3 refs.)

  10. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  11. Modeling of asymmetrical boost converters

    Directory of Open Access Journals (Sweden)

    Eliana Isabel Arango Zuluaga

    2014-03-01

    Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.

  12. HYDROGEN TRANSFER IN CATALYTIC CRACKING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Hydrogen transfer is an important secondary reaction of catalytic cracking reactions, which affects product yield distribution and product quality. It is an exothermic reaction with low activation energy around 43.3 kJ/mol. Catalyst properties and operation parameters in catalytic cracking greatly influence the hydrogen transfer reaction. Satisfactory results are expected through careful selection of proper catalysts and operation conditions.

  13. Increasing of Reliability of Converter

    Directory of Open Access Journals (Sweden)

    Trebuňa, F.

    2006-01-01

    Full Text Available The innovative activities in steel production invoke exploitation of new machines with the higher production capacity and productivity of labor. The paper deals with deformation and stress analysis of carrying parts of converter pedestal on the base of which the proposals and supporting measures were made that had the aim to increase reliability of the converter during steel production. This was achieved by lifespan prolongation of anchor and connecting bolts of converter pedestal, by change of stiffness of connected elements as well as by correction of nuts of bolted connections. The realization of structural changes decreased loading amplitudes and consequently the vibrations of pedestal. Solution was verified by numerical and experimental procedures of mechanics.

  14. Post combustion in converter steelmaking

    Energy Technology Data Exchange (ETDEWEB)

    Oghbasilasie, H.; Holappa, L.

    1997-12-31

    The purpose of this work is to study the fundamentals of post combustion and the effect of different process parameters on the post combustion ratio (PCR) and heat transfer efficiency (HTE) in converter steelmaking process. The PCR and HTE have been determined under normal operating conditions. Trials assessed the effect of lance height, vessel volume, foaming slag and pellet additions on PCR and HTE. Based on enthalpy considerations, post combustion of CO gas is regarded as one of the most effective means of increasing the heat supply to the BOP. The thermodynamic study of gas-metal-slag reactions gives the limiting conditions for post combustion inside the converter reactor. Different process parameters influencing both thermodynamic equilibria and kinetic conditions can greatly affect the post combustion ratio. Different features of converter processes as well smelting reduction processes utilizing post combustion have been reviewed. (orig.) SULA 2 Research Programme; 26 refs.

  15. Bifunctional catalytic electrode

    Science.gov (United States)

    Cisar, Alan (Inventor); Murphy, Oliver J. (Inventor); Clarke, Eric (Inventor)

    2005-01-01

    The present invention relates to an oxygen electrode for a unitized regenerative hydrogen-oxygen fuel cell and the unitized regenerative fuel cell having the oxygen electrode. The oxygen electrode contains components electrocatalytically active for the evolution of oxygen from water and the reduction of oxygen to water, and has a structure that supports the flow of both water and gases between the catalytically active surface and a flow field or electrode chamber for bulk flow of the fluids. The electrode has an electrocatalyst layer and a diffusion backing layer interspersed with hydrophilic and hydrophobic regions. The diffusion backing layer consists of a metal core having gas diffusion structures bonded to the metal core.

  16. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  17. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  18. One-Pot Catalytic Conversion of Cellulose and of Woody Biomass Solids to Liquid Fuels

    NARCIS (Netherlands)

    Matson, Theodore D.; Barta, Katalin; Iretskii, Alexei V.; Ford, Peter C.

    2011-01-01

    Efficient methodologies for converting biomass solids to liquid fuels have the potential to reduce dependence on imported petroleum while easing the atmospheric carbon dioxide burden. Here, we report quantitative catalytic conversions of wood and cellulosic solids to liquid and gaseous products in a

  19. Unsteady catalytic processes and sorption-catalytic technologies

    International Nuclear Information System (INIS)

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  20. Unsteady catalytic processes and sorption-catalytic technologies

    Energy Technology Data Exchange (ETDEWEB)

    Zagoruiko, A N [G.K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2007-07-31

    Catalytic processes that occur under conditions of the targeted unsteady state of the catalyst are considered. The highest efficiency of catalytic processes was found to be ensured by a controlled combination of thermal non-stationarity and unsteady composition of the catalyst surface. The processes based on this principle are analysed, in particular, catalytic selective reduction of nitrogen oxides, deep oxidation of volatile organic impurities, production of sulfur by the Claus process and by hydrogen sulfide decomposition, oxidation of sulfur dioxide, methane steam reforming and anaerobic combustion, selective oxidation of hydrocarbons, etc.

  1. Converting accounts receivable into cash.

    Science.gov (United States)

    Folk, M D; Roest, P R

    1995-09-01

    In recent years, increasing numbers of healthcare providers have converted their accounts receivable into cash through a process called securitization. This practice has gained popularity because it provides a means to raise capital necessary to healthcare organizations. Although securitization transactions can be complex, they may provide increased financial flexibility to providers as they prepare for continuing change in the healthcare industry. PMID:10145096

  2. Parametric study of laser photovoltaic energy converters

    Science.gov (United States)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  3. Trash to Gas: Converting Space Trash into Useful Products

    Science.gov (United States)

    Nur, Mononita

    2013-01-01

    NASA's Logistical Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is determined to reduce total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. LRR is focusing on four distinct advanced areas of study: Advanced Clothing System, Logistics-to-Living, Heat Melt Compactor and Trash to Supply Gas (TtSG). The objective of TtSG is to develop technologies that convert material waste, human waste and food waste into high-value products. High-value products include life support oxygen and water, rocket fuels, raw material production feedstocks, and other energy sources. There are multiple pathways for converting waste to products involving single or multi-step processes. This paper discusses thermal oxidation methods of converting waste to methane. Different wastes, including food, food packaging, Maximum Absorbent Garments (MAGs), human waste simulants, and cotton washcloths have been evaluated in a thermal degradation reactor under conditions promoting pyrolysis, gasification or incineration. The goal was to evaluate the degradation processes at varying temperatures and ramp cycles and to maximize production of desirable products and minimize high molecular weight hydrocarbon (tar) production. Catalytic cracking was also evaluated to minimize tar production. The quantities of C02, CO, CH4, and H20 were measured under the different thermal degradation conditions. The conversion efficiencies of these products were used to determine the best methods for producing desired products.

  4. Trash-to-Gas: Converting Space Trash into Useful Products

    Science.gov (United States)

    Caraccio, Anne J.; Hintze, Paul E.

    2013-01-01

    NASA's Logistical Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is determined to reduce total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. LRR is focusing on four distinct advanced areas of study: Advanced Clothing System, Logistics-to-Living, Heat Melt Compactor and Trash to Supply Gas (TtSG). The objective of TtSG is to develop technologies that convert material waste, human waste and food waste into high-value products. High-value products include life support oxygen and water, rocket fuels, raw material production feedstocks, and other energy sources. There are multiple pathways for converting waste to products involving single or multi-step processes. This paper discusses thermal oxidation methods of converting waste to methane. Different wastes, including food, food packaging, Maximum Absorbent Garments (MAGs), human waste simulants, and cotton washcloths have been evaluated in a thermal degradation reactor under conditions promoting pyrolysis, gasification or incineration. The goal was to evaluate the degradation processes at varying temperatures and ramp cycles and to maximize production of desirable products and minimize high molecular weight hydrocarbon (tar) production. Catalytic cracking was also evaluated to minimize tar production. The quantities of CO2, CO, CH4, and H2O were measured under the different thermal degradation conditions. The conversion efficiencies of these products were used to determine the best methods for producing desired products.

  5. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  6. Catalytic gasification of biomass

    Science.gov (United States)

    Robertus, R. J.; Mudge, L. K.; Sealock, L. J., Jr.; Mitchell, D. H.; Weber, S. L.

    1981-12-01

    Methane and methanol synthesis gas can be produced by steam gasification of biomass in the presence of appropriate catalysts. This concept is to use catalysts in a fluidized bed reactor which is heated indirectly. The objective is to determine the technical and economic feasibility of the concept. Technically the concept has been demonstrated on a 50 lb per hr scale. Potential advantages over conventional processes include: no oxygen plant is needed, little tar is produced so gas and water treatment are simplified, and yields and efficiencies are greater than obtained by conventional gasification. Economic studies for a plant processing 2000 T/per day dry wood show that the cost of methanol from wood by catalytic gasification is competitive with the current price of methanol. Similar studies show the cost of methane from wood is competitive with projected future costs of synthetic natural gas. When the plant capacity is decreased to 200 T per day dry wood, neither product is very attractive in today's market.

  7. Relation between the structure and catalytic activity for automotive emissions. Use of x-ray anomalous dispersion effect

    CERN Document Server

    Mizuki, J; Tanaka, H

    2003-01-01

    The employment of the X-ray anomalous dispersion effect allows us to detect the change in structure of catalytic converters with the environment exposed. Here we show that palladium atoms in a perovskite crystal move into and out of the crystal by anomalous X-ray diffraction and absorption techniques. This movement of the precious metal plays an important role to keep the catalytic activity long-lived. (author)

  8. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brownian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d=3.

  9. Immigration process in catalytic medium

    Institute of Scientific and Technical Information of China (English)

    洪文明; 王梓坤

    2000-01-01

    The longtime behavior of the immigration process associated with a catalytic super-Brown-ian motion is studied. A large number law is proved in dimension d≤3 and a central limit theorem is proved for dimension d = 3.

  10. Vibration converter with magnetic levitation

    Science.gov (United States)

    Gladilin, A. V.; Pirogov, V. A.; Golyamina, I. P.; Kulaev, U. V.; Kurbatov, P. A.; Kurbatova, E. P.

    2015-05-01

    The paper presents a mathematical model, the results of computational and theoretical research, and the feasibility of creating a vibration converter with full magnetic levitation in the suspension of a high-temperature superconductor (HTSC). The axial and radial stability of the active part of the converter is provided by the interaction of the magnetic field of ring-shaped permanent magnets and a hollow cylinder made of the ceramic HTSC material. The force is created by a system of current-carrying coils whose magnetic field is polarized by permanent magnets and interacts with induced currents in the superconducting cylinder. The case of transition to the superconducting state of HTSC material in the field of the permanent magnets (FC mode) is considered. The data confirm the outlook for the proposed technical solutions.

  11. Photoelectric converters with quantum coherence

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency ηCA. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to ηCA through manipulation of carefully controlled quantum coherences.

  12. Collector for thermionic energy converter

    International Nuclear Information System (INIS)

    An improved collector is provided for a thermionic energy converter. The collector comprises a p-type layer of a semiconductor material formed on an n-type layer of a semiconductor material. The p-n junction is maintained in a forward biased condition. The electron affinity of the exposed surface of the p-type layer is effectively lowered to a low level near zero by the presence of a work function lowering activator. The dissipation of energy during collection is reduced by the passage of electrons through the p-type layer in the metastable conduction band state. A significant portion of the electron current remains at the potential of the fermi level of the n-type layer rather than dropping to the fermi level of the p-type layer. Less energy is therefore dissipated as heat and a higher net power output is delivered from a thermionic energy converter incorporating the collector

  13. Efficiency of Capacitively Loaded Converters

    DEFF Research Database (Denmark)

    Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.;

    2012-01-01

    is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging......This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... efficiency of converter. Based on the capacitancevoltage curve, the correct capacitance should be chosen when calculating the stored energy; otherwise misleading optimistic efficiency can always be obtained. Actually, when DEAP actuator is not available at the early developing stage, the voltage independent...

  14. Radiated EMI from power converters

    Directory of Open Access Journals (Sweden)

    Arnautovski-Toševa Vesna

    2005-01-01

    Full Text Available With the continuous increase of switching frequency together with the ongoing trend to higher complexity and functionality, power converters as a part of electronic systems have raised more and more electromagnetic energy pollution to the local system environment. In the same time, stringent demands are imposed on the designers of new circuits that electromagnetic interference (EMI has to be suppressed at its source before it is allowed to propagate into other circuits and systems. In this paper, the authors present a full-wave numerical method for calculation and simulation of electromagnetic field radiated by power converter circuitry. The main objective is to analyze the layout geometry in order to obtain competitive PCB layout that will enable suitably attenuated level of the radiated electric field to safe level. By this it would be possible to ensure reliable operation of the sensitive electronic components in the proximity.

  15. Photoelectric converters with quantum coherence.

    Science.gov (United States)

    Su, Shan-He; Sun, Chang-Pu; Li, Sheng-Wen; Chen, Jin-Can

    2016-05-01

    Photon impingement is capable of liberating electrons in electronic devices and driving the electron flux from the lower chemical potential to higher chemical potential. Previous studies hinted that the thermodynamic efficiency of a nanosized photoelectric converter at maximum power is bounded by the Curzon-Ahlborn efficiency η_{CA}. In this study, we apply quantum effects to design a photoelectric converter based on a three-level quantum dot (QD) interacting with fermionic baths and photons. We show that, by adopting a pair of suitable degenerate states, quantum coherences induced by the couplings of QDs to sunlight and fermion baths can coexist steadily in nanoelectronic systems. Our analysis indicates that the efficiency at maximum power is no longer limited to η_{CA} through manipulation of carefully controlled quantum coherences.

  16. Development of a Compact Matrix Converter

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2009-01-01

    Full Text Available This paper deals with the development of a matrix converter. Matrix converters belong to the category of direct frequency converters. A converter does not contain DC-link and the output voltage is provided by direct switching of voltage from the input phases. This is enabled by 9 bidirectional switches, which are provided by anti-serial connection of 18 IGBT transistors. The absence of a DC-link is great advantage of the matrix converter, but it also increases the requirements on the converter control. For this reason a new prototype of a matrix converter is being developed with sophisticated modern components (FPGA, Power PC equipped in the control part of the converter. The converter will be used for testing new control algorithms and commutation methods. 

  17. Biomass compounds converted to gasoline

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-08

    It is claimed that corn, castor, and jojoba oils as well as Hevea latex can be converted in high yields to gasoline by passage over zeolite catalysts at 450 degrees to 500 degrees centigrade. Gasoline yields are 60% from corn oil (essentially tristearin), compared with 50% yields from methanol. Latex depolymerizes before conversion. Fat and oil molecules adopt conformations that enable them to enter zeolite interstices, resulting in high yields of C6 to C9 aromatics.

  18. EMI Prediction of Switching Converters

    OpenAIRE

    Trinchero, Riccardo; Stievano, Igor Simone; Canavero, Flavio

    2015-01-01

    This paper addresses the simulation of the conducted electromagnetic interference produced by circuits with periodically switching elements. The proposed method allows for the computation of their steady-state responses by means of augmented linear time-invariant equivalents built from circuit inspection only, and standard tools for circuit analysis. The approach is demonstrated on a real dc-dc boost converter by comparing simulation results with real measurements

  19. Resonant Demagnetization PWM Forward Converter

    OpenAIRE

    BİLGİN, Bülent

    2003-01-01

    In this paper, a new approach to demagnetization process of a PWM forward converter (FC) is proposed. According to this approach, the demagnetization winding and diode of a conventional FC are removed, and an external capacitor is added in parallel with the secondary diode. This replacement changes the linear demagnetization process of a conventional FC into a resonant demagnetization process. The theoretical performance results of the proposed resonant demagnetization forward conve...

  20. Radiated EMI from power converters

    OpenAIRE

    Arnautovski-Toševa Vesna; Rousset Yanis; Drissi El Khamlichi Khalil; Grčev Leonid

    2005-01-01

    With the continuous increase of switching frequency together with the ongoing trend to higher complexity and functionality, power converters as a part of electronic systems have raised more and more electromagnetic energy pollution to the local system environment. In the same time, stringent demands are imposed on the designers of new circuits that electromagnetic interference (EMI) has to be suppressed at its source before it is allowed to propagate into other circuits and systems. In this p...

  1. Design and Control for the Buck-Boost Converter Combining 1-Plus-D Converter and Synchronous Rectified Buck Converters

    Directory of Open Access Journals (Sweden)

    Jeevan Naik

    2015-06-01

    Full Text Available In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.

  2. Computerized simulation of converter process

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, H.; Suomi, M.L.; Wallgren, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

    1996-12-31

    Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.

  3. Simulation Results of Double Forward Converter

    Directory of Open Access Journals (Sweden)

    P. Vijaya KUMAR

    2009-12-01

    Full Text Available This work aims to find a better forward converter for DC to DC conversion.Simulation of double forward converter in SMPS system is discussed in this paper. Aforward converter with RCD snubber to synchronous rectifier and/or to current doubleris also discussed. The evolution of the forward converter is first reviewed in a tutorialfashion. Performance parameters are discussed including operating principle, voltageconversion ratio, efficiency, device stress, small-signal dynamics, noise and EMI. Itscircuit operation and its performance characteristics of the forward converter with RCDsnubber and double forward converter are described and the simulation results arepresented.

  4. Catalytic Conversion of Carbohydrates

    DEFF Research Database (Denmark)

    Osmundsen, Christian Mårup

    Modern civilization is dependent on oil to supply energy for power, heating and transportation and carbon for the production of the plethora of chemicals needed. Oil is however a limited resource and alternatives need to be identified before we freeze in the dark [1]. This thesis deals with the p......Modern civilization is dependent on oil to supply energy for power, heating and transportation and carbon for the production of the plethora of chemicals needed. Oil is however a limited resource and alternatives need to be identified before we freeze in the dark [1]. This thesis deals......-BEA was studied using DFT calculations, which indicate that the strongest, and most stable, acid site is formed through the introduction of a silicon vacancy adjacent to the tin site. Aromatics are an important class of compounds. In particular benzene, toluene and p-xylene finds use in a wide range of industries...... a renewable route to aromatics. The conversion of biomass by high temperature processes is a desirable prospect due to the high volumetric production rates which can be achieved, and the ability of these types of processes to convert a wide range of substrates. Current processes however typically have rather...

  5. OAM mode converter in twisted fibers

    DEFF Research Database (Denmark)

    Usuga Castaneda, Mario A.; Beltran-Mejia, Felipe; Cordeiro, Cristiano;

    2014-01-01

    We analyze the case of an OAM mode converter based on a twisted fiber, through finite element simulations where we exploit an equivalence between geometric and material transformations. The obtained converter has potential applications in MDM. © 2014 OSA....

  6. Analysis Of Single Phase Matrix Converter

    OpenAIRE

    Divya Ahirrao; Bhagyashri Gaware

    2014-01-01

    This paper presents concept of single phase matrix converter. Single phase matrix converter (SPMC) performs a function such as frequency changer, rectifier, inverter; chopper. This reduces the need for new converter hardware. Pulse width modulation (SPWM) techniques are used to calculate the switch duty ratio to synthesis the output. The simulation of converter is carried out in MATLAB/SIMULINK. Hardware design is obtained using readily available IC‟s and other components. Thi...

  7. Simulation Results of Double Forward Converter

    OpenAIRE

    P. Vijaya Kumar; S. Rama Reddy

    2009-01-01

    This work aims to find a better forward converter for DC to DC conversion.Simulation of double forward converter in SMPS system is discussed in this paper. Aforward converter with RCD snubber to synchronous rectifier and/or to current doubleris also discussed. The evolution of the forward converter is first reviewed in a tutorialfashion. Performance parameters are discussed including operating principle, voltageconversion ratio, efficiency, device stress, small-signal dynamics, noise and EMI....

  8. Digital to Analog Converter Description

    OpenAIRE

    Tuijl, van, B.A.J.

    2003-01-01

    A circuit for analogue to digital or digital to analogue conversion comprising at least 2n matched current sources (40-1, 40-2, 40-n), where n is the resolution required of the conversion. Preferably more than 2n current sources (40-1, 40-2, 40-n) are used. The order in which the sources (40-1, 40-2, 40-n) are used may be changed in different samples. The current sources (40-1, 40-2, 40-n) may be replaced by one bit switched capacitor converters or by inverters connected to one end of a set o...

  9. Reliability of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon

    There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs to become successful and more competitive to other renewable electricity sources, the consideration of the structural reliability of WECs is essential...... approach that includes uncertainties related to the limited amount of data and the considered models used to calculate the loads/stresses as well as uncertainties given by Mother Nature (e.g. inter-annual variation of extreme values) and measurement uncertainties. Due to limited amount of knowledge...

  10. Reliability of Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon

    There are many different working principles for wave energy converters (WECs) which are used to produce electricity from waves. In order for WECs tobecome successful and more competitive to other renewable electricity sources,the consideration of the structural reliability of WECs is essential...... uncertaintiesrelated to the limited amount of data and the considered models used tocalculate the loads/stresses as well as uncertainties given by Mother Nature (e.g. inter-annual variation of extreme values) and measurement uncertainties. Due to limited amount of knowledge, reliability considerations for WEC...

  11. Power Converters and Power Quality

    CERN Document Server

    Kahle, K

    2015-01-01

    This paper discusses the subject of power quality for power converters. The first part gives an overview of most of the common disturbances and power quality issues in electrical networks for particle accelerators, and explains their consequences for accelerator operation. The propagation of asymmetrical network disturbances into a network is analysed. Quantitative parameters for network disturbances in a typical network are presented, and immunity levels for users’ electrical equipment are proposed. The second part of this paper discusses the technologies and strategies used in particle accelerator networks for power quality improvement . Particular focus is given to networks supplying loads with cycling active and reactive power

  12. Underwater noise from a wave energy converter

    DEFF Research Database (Denmark)

    Tougaard, Jakob

    A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...

  13. Catalytic distillation water recovery subsystem

    Science.gov (United States)

    Budininkas, P.; Rasouli, F.

    1985-01-01

    An integrated engineering breadboard subsystem for the recovery of potable water from untreated urine based on the vapor phase catalytic ammonia removal was designed, fabricated and tested. Unlike other evaporative methods, this process catalytically oxidizes ammonia and volatile hydrocarbons vaporizing with water to innocuous products; therefore, no pretreatment of urine is required. Since the subsystem is fabricated from commercially available components, its volume, weight and power requirements are not optimized; however, it is suitable for zero-g operation. The testing program consists of parametric tests, one month of daily tests and a continuous test of 168 hours duration. The recovered water is clear, odorless, low in ammonia and organic carbon, and requires only an adjustment of its pH to meet potable water standards. The obtained data indicate that the vapor phase catalytic ammonia removal process, if further developed, would also be competitive with other water recovery systems in weight, volume and power requirements.

  14. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  15. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne;

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...... with particle size. We find that the fraction of low-coordinated Au atoms scales approximately with the catalytic activity, suggesting that atoms on the corners and edges of Au nanoparticles are the active sites. This effect is explained using density functional calculations....

  16. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Christpher P; Boldingh, Edwin P

    2013-12-17

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and show to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hyrdocarbons into hydrocarbons removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  17. Catalytic pyrolysis using UZM-39 aluminosilicate zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Christopher P; Boldingh, Edwin P

    2014-10-07

    A new family of coherently grown composites of TUN and IMF zeotypes has been synthesized and shown to be effective catalysts for catalytic pyrolysis of biomass. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.n+R.sub.rQ.sub.qAl.sub.1-xE.sub.xSi.sub.yO.s- ub.z where M represents zinc or a metal or metals from Group 1, Group 2, Group 3 or the lanthanide series of the periodic table, R is an A,.OMEGA.-dihalosubstituted paraffin such as 1,4-dibromobutane, Q is a neutral amine containing 5 or fewer carbon atoms such as 1-methylpyrrolidine and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-39 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

  18. Reactive Power Compensation using a Matrix Converter

    OpenAIRE

    Holtsmark, Nathalie Marie-Anna

    2010-01-01

    This Master's thesis investigates a new application for the matrix converter: Shunt reactive power compensation. The suggested Matrix Converter-based Reactive power Compensation (MCRC) device is composed of a matrix converter, which input is connected to the grid and an electric machine at the output of the converter. The reactive power flowing in or out of the grid can be regulated with the matrix converter by controlling the magnitude and/or phase angle of the current at the input of the co...

  19. Valuing Convertible Bonds Based on LSRQM Method

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2014-01-01

    Full Text Available Convertible bonds are one of the essential financial products for corporate finance, while the pricing theory is the key problem to the theoretical research of convertible bonds. This paper demonstrates how to price convertible bonds with call and put provisions using Least-Squares Randomized Quasi-Monte Carlo (LSRQM method. We consider the financial market with stochastic interest rates and credit risk and present a detailed description on calculating steps of convertible bonds value. The empirical results show that the model fits well the market prices of convertible bonds in China’s market and the LSRQM method is effective.

  20. Analysis Of Single Phase Matrix Converter

    Directory of Open Access Journals (Sweden)

    Divya Ahirrao

    2014-03-01

    Full Text Available This paper presents concept of single phase matrix converter. Single phase matrix converter (SPMC performs a function such as frequency changer, rectifier, inverter; chopper. This reduces the need for new converter hardware. Pulse width modulation (SPWM techniques are used to calculate the switch duty ratio to synthesis the output. The simulation of converter is carried out in MATLAB/SIMULINK. Hardware design is obtained using readily available IC‟s and other components. This paper discusses the new multiple converter for single phase input using matrix topology using just a single control logic.

  1. Analysis of Platinum Content in Used Auto Catalytic Converter Carriers and the Possibility of its Recovery

    Directory of Open Access Journals (Sweden)

    Saternus M.

    2014-06-01

    Full Text Available Obecnie każdy wyprodukowany samochód musi być wyposażony w katalizator, w którym metale szlachetne takie jak platyna, pallad czy rod pełnią funkcje katalityczne. Czas życia katalizatorów jest ograniczony, zatem zostają one zastąpione nowymi, a stare stanowią ważne źródło platynowców. Zużyte katalizatory samochodowe przerabiane są hydrometalurgicznie lub pirometalurgicznie. Jednakże pierwszym etapem takiego przerobu powinna być analiza chemiczna. W pracy analizie na zawartość platyny poddano kilka różnych nośników katalitycznych pochodzących z różnych samochodów. Do tego celu posłużył elektronowy mikroskop skaningowy. Przedstawiono strukturę analizowanych nośników katalitycznych, ich analizę chemiczną jak również wykresy EDS (Energy Dispersive Spectrum. Przeprowadzono dyskusję wyników i możliwych metod odzysku platyny.

  2. Three-way catalytic converter modelling. Numerical determination of kinetic data

    Energy Technology Data Exchange (ETDEWEB)

    Dubien, C.; Schweich, D. [Laboratoire de Genie des Precedes Catalytiques, Villeurbanne cedex (France)

    1998-12-31

    A numerical approach for obtaining quickly and simply kinetic data from light-off curves is proposed. It is applied to methane oxidation which exhibits light-off at a much higher temperature than the other pollutants. Sensitivity analysis shows that heat loss is secondary and a simple 1-D adiabatic model can be used. Conversions calculated from the estimated kinetic parameters are close to experimental values. Finally, the effects of the apparent activation energy and frequency factor are discussed through a relation that links the rate constants to the light-off temperature. 10 refs.

  3. Analysis of Platinum Content in Used Auto Catalytic Converter Carriers and the Possibility of its Recovery

    OpenAIRE

    Saternus M.; Fornalczyk A.; Cebulski J.

    2014-01-01

    Obecnie każdy wyprodukowany samochód musi być wyposażony w katalizator, w którym metale szlachetne takie jak platyna, pallad czy rod pełnią funkcje katalityczne. Czas życia katalizatorów jest ograniczony, zatem zostają one zastąpione nowymi, a stare stanowią ważne źródło platynowców. Zużyte katalizatory samochodowe przerabiane są hydrometalurgicznie lub pirometalurgicznie. Jednakże pierwszym etapem takiego przerobu powinna być analiza chemiczna. W pracy analizie na zawartość platyny poddano k...

  4. 汽车尾气催化转化器%Exhaust Gas Catalytic Converter for Automobiles

    Institute of Scientific and Technical Information of China (English)

    谭强

    2000-01-01

    简要介绍了汽车尾气催化转化器的结构、材料工艺和性能.综合比较了稀土-贱金属复合氧化物催化剂、稀土贱金属-微量贵金属催化剂和贵金属-少量稀土催化剂的材料和特性.给出了几种典型贵金属-稀土金属催化剂的配方.

  5. 催化转化器的研究进展%Research Rrogress of Catalytic Converters

    Institute of Scientific and Technical Information of China (English)

    肖丹妮; 靳超; 袁万里

    2015-01-01

    随着国家对环保问题重视程度的提高,对车辆废气排放要求也相应地增加.结合摩托车尾气排放问题,对催化转化器在降低CO、HC和NOx等方面发挥的作用进行了介绍,详细阐述了催化转化器的定义、组成和反应原理,论述了在一定范围内贵金属组分铂、钯、铑的含量越大,催化效率越高,同时其催化活性与贵金属铂、钯、铑的粒径也成线性关系;催化转化器载体孔壁厚度越薄和孔密度越大催化效率越高;汽油品质越好,含硫量越低,催化效率越高;根据不同车型的排放要求,选择合适的温度、排气系统空燃比,使其达到最佳的排放效果.

  6. Studies on Exhaust Emissions from Copper-Coated Gasohol Run Spark Ignition Engine with Catalytic Converter

    OpenAIRE

    S. Narasimha Kumar*1; Kishor, K.; M.V.S. Murali Krishna; P.V.K.Murthy

    2011-01-01

    The major pollutants emitted from spark ignition engine are carbon monooxide (CO) and unburnt hydrocarbons (UHC). These are hazardous and cause health problems to human beings, and hence control of these pollutants calls for immediate attention. Copper of thickness 300 microns is coated over piston crown and inside portion of the cylinder head of the spark ignition engine. Investigations have been carried out for reducing pollutants from a variable compression ratio, copper-coated spark ignit...

  7. New tests for characterizing the durability of a ceramic catalytic converter package

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K.P.; Helfinstine, J.D.; Gulati, S.T. [Corning, Inc., NY (United States)

    1996-09-01

    New test methods were developed to characterize the high temperature durability of intumescent mats that are used to mount ceramic catalyst supports in stainless steel cans. The key attribute of these tests is the use of an electric resistance heating method to maintain a temperature gradient through the thickness of the mat when a cyclic or constant shear stress is applied to the mat interface. These tests are simple to perform and do not require expensive equipment or highly skilled operators. Using these new test methods, the durability of ceramic preconverters mounted with 4,070 gm/m{sup 2} intumescent mat was studied. The results of these tests indicate that a preconverter package with 4070 gm/m{sup 2} intumescent mat can perform satisfactorily in the close-coupled application where temperatures exceed 900 C. The mat performance can be quantified in terms of applied stress and test temperature by utilizing the experimental methods described in the present study.

  8. Demonstration of lean NOx catalytic converter technology on a heavy-duty diesel engine. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Heimrich, M.J.

    1996-05-01

    Experimental catalysts for the reduction of oxides of nitrogen (NOx) were evaluated on a 258-horsepower (192 kW) direct-injection heavy-duty diesel engine. An experimental reductant delivery system provided supplementary hydrocarbons for the reduction of NOx. A fuel economy penalty of five percent was measured for initial FTP experiments.

  9. Dielectric heating catalytic converter system for reducing cold-start emissions

    Energy Technology Data Exchange (ETDEWEB)

    Takatsu, Katsumi; Kurogi, Fumiyasu; Matsue, Akihiro; Kasaya, Masashi

    1996-09-01

    To reduce the harmful pollutants in cold start emissions, this study has been considering microwave dielectric technique for rapid catalyst heating. A dielectric material, having a relatively large loss factor at 2.45GHz was selected. This was coated to the exhaust catalyst allowing microwave energy to be deposited efficiently. The developed system has been tested successfully using a single-mode cavity in conjunction with a model gas. Moreover, a concept for practical in-vehicle system using the microwave heated catalyst has been proposed.

  10. BMW 750i with electrically heated catalytic converter; BMW 750i mit elektrisch beheiztem Katalysator

    Energy Technology Data Exchange (ETDEWEB)

    Kiefer, W.; Plodek, B.; Ehmann, P. [BMW AG, Muenchen (Germany); Feldwisch-Drentrup, R. [Engelhard Technologies GmbH (Germany); Diringer, J. [Emitec Gesellschaft fuer Emissionstechnologie mbH (Germany)

    1998-11-01

    The twelve-cylinder BMW engine employed in the top-of-the-range 750i is also to be equipped with cutting-edge emission control technology for the 1999 model year in order to meet the planned statutory requirements for EU stages 3 and 4, and of LEV for California. A forward-looking emission concept for fulfilment of the world`s strictest emission limits has been drawn up for this purpose. Additional technical measures have been employed in order to reduce fuel consumption and to underline BMW`s commitment to producing `the ultimate driving machine`. (orig.) [Deutsch] Der BMW Zwoelfzylindermotor, der im Topmodell 750i eingesetzt wird, sollte fuer das Modelljahr 1999 auch bezueglich der Emissionen mit Spitzentechnik zur Erfuellung der geplanten Gesetzesanforderungen fuer EU 3 und EU 4 sowie LEV fuer Kalifornien ausgestattet werden. Hierfuer wurde ein zukunftsweisendes Emissionskonzept zur Erfuellung der weltweit schaerfsten Abgasgrenzwerte entwickelt. Zusaetzliche technische Massnahmen dienen dazu, den Kraftstoffverbrauch zu verbessern. (orig.)

  11. DNA replication: polymerase epsilon as a non-catalytic converter of the helicase.

    Science.gov (United States)

    Zegerman, Philip

    2013-04-01

    In eukaryotes DNA polymerase epsilon (ε) synthesises the leading DNA strand during replication. A new study provides insight into how this polymerase also functions independently of its enzyme activity to assemble and activate the replicative helicase. PMID:23578873

  12. Preliminary Characterization of a Coaxial DBD Plasma-Catalytic Converter for Methane Partial Oxidation

    Science.gov (United States)

    Coulombe, Sylvain; Diaz Gomez Maqueo, Pablo; Evans, Mathew; Sainct, Florent; Bergthorson, Jeff

    2015-09-01

    This contribution discusses the development and characteristics of a coaxial dielectric barrier discharge (DBD) using a methane-oxygen mixture at atmospheric conditions of temperature and pressure. A sinusoidal voltage waveform of 12 kVp-p at 20 kHz produces discharges in a 1.15 mm gap. Power is estimated using a Lissajous figure method while optical emission spectroscopy (OES) is used to estimate the rotational and vibrational temperatures of the gas. Obtained OES spectra are similar, differing mainly on the intensity of their CH and OH bands, tending towards a more intense OH band as oxygen availability increased. CH bands show the strongest emission intensities of which, CH(C-X) seems to be the most intense of all, followed by CH(A-X) and lastly by CH(B-X). The spectra of CH(A-X) and CH(C-X) were uploaded into a simulation software to estimate the plasma temperatures. For the CH(A-X) bands, a simulation with a Trot = 600 K and a Tvib = 6000 K matched the experimental spectra. In the case of the CH(C-X) band, a Trot = 800 K and a Tvib = 4000 K were determined. The vibrational temperatures are especially high, a result which is particularly important for the development of a plasma-catalysis reactor. The authors acknowledge the financial support provided by NSERC, FRQNT as well as McGill University through the McGill Engineering Doctoral Award program.

  13. Effectiveness of replacing catalytic converters in LPG-fueled vehicles in Hong Kong

    Science.gov (United States)

    Lyu, Xiaopu; Guo, Hai; Simpson, Isobel J.; Meinardi, Simone; Louie, Peter K. K.; Ling, Zhenhao; Wang, Yu; Liu, Ming; Luk, Connie W. Y.; Wang, Nan; Blake, Donald R.

    2016-05-01

    Many taxis and public buses are powered by liquefied petroleum gas (LPG) in Hong Kong. With more vehicles using LPG, they have become the major contributor to ambient volatile organic compounds (VOCs) in Hong Kong. An intervention program which aimed to reduce the emissions of VOCs and nitrogen oxides (NOx) from LPG-fueled vehicles was implemented by the Hong Kong government in September 2013. Long-term real-time measurements indicated that the program was remarkably effective in reducing LPG-related VOCs, NOx and nitric oxide (NO) in the atmosphere. Receptor modeling results further revealed that propane, propene, i-butane, n-butane and NO in LPG-fueled vehicle exhaust emissions decreased by 40.8 ± 0.1, 45.7 ± 0.2, 35.7 ± 0.1, 47.8 ± 0.1 and 88.6 ± 0.7 %, respectively, during the implementation of the program. In contrast, despite the reduction of VOCs and NOx, O3 following the program increased by 0.40 ± 0.03 ppbv (˜ 5.6 %). The LPG-fueled vehicle exhaust was generally destructive to OH and HO2. However, the destruction effect weakened for OH and it even turned to positive contribution to HO2 during the program. These changes led to the increases of OH, HO2 and HO2 / OH ratio, which might explain the positive O3 increment. Analysis of O3-VOCs-NOx sensitivity in ambient air indicated VOC-limited regimes in the O3 formation before and during the program. Moreover, a maximum reduction percentage of NOx (i.e., 69 %) and the lowest reduction ratio of VOCs / NOx (i.e., 1.1) in LPG-fueled vehicle exhaust were determined to give a zero O3 increment. The findings are of great help to future formulation and implementation of control strategies on vehicle emissions in Hong Kong, and could be extended to other regions in China and around the world.

  14. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-05-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 s. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  15. Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

    Directory of Open Access Journals (Sweden)

    S. J. Solomon

    2005-01-01

    Full Text Available A novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 seconds. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol.

  16. High-Performance Data Converters

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    -order difference of the output signal from the loop filter's first integrator stage. This technique avoids the need for accurate matching of analog and digital filters that characterizes the MASH topology, and it preserves the signal-band suppression of quantization errors. Simulations show that quantizers...... in a standard CMOS technology, they can be designed to yield 100 dB performance at 10 times oversampling. The proposed scaled-element mismatch-shaping D/A converters are well suited for use as the feedback stage in oversampled delta-sigma quantizers. It is, however, not easy to make full use of their potential......, because that requires a high-resolution loop quantizer which introduces only a small delay. Generally, it is not acceptable to design the loop quantizer as a high-resolution flash quantizer because they require a large chip area and high power consumption. Pipeline techniques are proposed to circumvent...

  17. The SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Kofoed, Jens Peter;

    2012-01-01

    The Sea-wave Slot-cone Generator concept (SSG) is a Wave Energy Converter based on the wave overtopping principle utilizing several reservoirs placed on top of each other, in which the energy of the incoming wave will be stored as potential energy. The water captured in the reservoirs will then run...... through turbines for electricity production. The system utilizes a wide spectrum of different wave conditions by means of multiple reservoirs, located at different levels above the still water level. Thereby, it obtains a high overall efficiency and it can be suitable for shoreline and breakwater...... applications, presenting particular advantages such as: sharing structure costs, availability of grid connection and infrastructures, recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installation were in progress...

  18. Converting pest insects into food

    DEFF Research Database (Denmark)

    Offenberg, Hans Joachim; Wiwatwittaya, Decha

    2010-01-01

    by pest insects, problematic pests are converted into food and additional earnings. To assess the profitability of providing additional food for the ants, O. smaragdina food conversion efficiency (ECI) was estimated in the laboratory. This estimate suggests the feeding of weaver ants in ant farms......Canopy dwelling weaver ants (Oecophylla spp.) are used to control a variety of pests in a number of tropical tree crops. What is less familiar is the existence of commercial markets where these ants and their brood are sold for (i) human consumption, (ii) pet food or (iii) traditional medicine...... on management, 32-115 kg ant brood (mainly new queens) was harvested per ha per year without detrimental effect on colony survival and worker ant densities. This suggest that ant biocontrol and ant harvest can be sustainable integrated in plantations and double benefits derived. As ant production is fuelled...

  19. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author)

  20. Simple, chemoselective, catalytic olefin isomerization.

    Science.gov (United States)

    Crossley, Steven W M; Barabé, Francis; Shenvi, Ryan A

    2014-12-01

    Catalytic amounts of Co(Sal(tBu,tBu))Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.

  1. High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to gamma-valerolactone

    NARCIS (Netherlands)

    Luo, Wenhao; Meenakshisundaram, Sankar; Beale, Andrew M.; He, Qian; Kiely, Christopher J.; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2015-01-01

    The catalytic hydrogenation of levulinic acid, a key platform molecule in many biorefinery schemes, into gamma-valerolactone is considered as one of the pivotal reactions to convert lignocellulose-based biomass into renewable fuels and chemicals. Here we report on the development of highly active, s

  2. Simultaneous fast pyrolysis and catalytic upgrading of lignin to obtain a marine diesel fuel

    DEFF Research Database (Denmark)

    Zhou, Guofeng

    The topic of this Ph.D. project is to convert lignin, a by-product from a 2nd generation bio-ethanol plant, into a marine diesel fuel by fast pyrolysis followed with catalytic upgrading of the pyrolysis vapor. Lignin, a major component of lignocellulosic biomass, is underutilized in the 2nd...... generation bio-ethanol plants. Shipping industry on the other hand is looking for clean alternative fuels in order to meet stricter fuel quality and emission standards. To convert lignin into a renewable marine diesel fuel will both accelerate the development of modern bio-refinery and transfer the marine...

  3. Three-phase AC-AC power converters based on matrix converter topology matrix-reactance frequency converters concept

    CERN Document Server

    Szczesniak, Pawel

    2013-01-01

    AC voltage frequency changes is one of the most important functions of solid state power converters. The most desirable features in frequency converters are the ability to generate load voltages with arbitrary amplitude and frequency, sinusoidal currents and voltages waveforms; the possibility of providing unity power factor for any load; and, finally, a simple and compact power circuit. Over the past decades, a number of different frequency converter topologies have appeared in the literature, but only the converters with either a voltage or current DC link are commonly used in industrial app

  4. CATALYTIC CONVERSION OF FORMIC ACID TO METHANOL WITH Cu AND Al UNDER HYDROTHERMAL CONDITIONS

    Directory of Open Access Journals (Sweden)

    Hansong Yao,

    2012-01-01

    Full Text Available Catalytic conversion of formic acid into methanol was investigated with Cu as a catalyst and Al as a reductant under hydrothermal conditions. It was found that formic acid can be converted into methanol by such means. The highest yield of methanol (30.4% was attained with a temperature of 300 °C and a reaction time of 9 h. The AlO(OH formed from Al oxidation may also play a catalytic role in the formation of methanol. This process may provide a promising solution to producing methanol from carbohydrate biomass combined with the process of converting the carbohydrate into formic acid, which is expected to emit no CO2.

  5. Incorporation of catalytic dehydrogenation into fischer-tropsch synthesis to significantly reduce carbon dioxide emissions

    Energy Technology Data Exchange (ETDEWEB)

    Huffman, Gerald P.

    2012-11-13

    A new method of producing liquid transportation fuels from coal and other hydrocarbons that significantly reduces carbon dioxide emissions by combining Fischer-Tropsch synthesis with catalytic dehydrogenation is claimed. Catalytic dehydrogenation (CDH) of the gaseous products (C1-C4) of Fischer-Tropsch synthesis (FTS) can produce large quantities of hydrogen while converting the carbon to multi-walled carbon nanotubes (MWCNT). Incorporation of CDH into a FTS-CDH plant converting coal to liquid fuels can eliminate all or most of the CO.sub.2 emissions from the water-gas shift (WGS) reaction that is currently used to elevate the H.sub.2 level of coal-derived syngas for FTS. Additionally, the FTS-CDH process saves large amounts of water used by the WGS reaction and produces a valuable by-product, MWCNT.

  6. Radiation-Tolerant DC-DC Converters

    Science.gov (United States)

    Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

    2012-01-01

    A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

  7. Converting Relational Database Into Xml Document

    Directory of Open Access Journals (Sweden)

    Kanagaraj.S

    2012-03-01

    Full Text Available XML (Extensible Markup Language is emerging and gradually accepted as the standard for data interchange in the Internet world. Interoperation of relational database and XML database involves schema and data translations. Through EER (extended entity relationship model can convert the schema of relational database into XML. The semantics of the relational database, captured in EER diagram, are mapped to XML schema using stepwise procedures and mapped to XML document under the definitions of the XML schema. Converting Relational Database into XML Document is a process of converting the existing databases into XML file format. Existing conversion techniques convert a single database into xml. The proposed approach performs the conversion of databases like Ms-Access, MS-SQL to XML file format. Read the tables information from the corresponding database and generate code for the appropriate databases and convert the tables into XML flat file format. This converted XML file is been presented to the user.

  8. High Efficiency Reversible Fuel Cell Power Converter

    DEFF Research Database (Denmark)

    Pittini, Riccardo

    entitled "High Efficiency Reversible Fuel Cell Power Converter" and it presents the design of a high efficiency dc-dc converter developed and optimized for bidirectional fuel cell applications. First, a brief overview of fuel cell and energy storage technologies is presented. Different system topologies...... as well as different dc-ac and dc-dc converter topologies are presented and analyzed. A new ac-dc topology for high efficiency data center applications is proposed and an efficiency characterization based on the fuel cell stack I-V characteristic curve is presented. The second part discusses the main...... of magnetic components especially for large production volumes. At last, the complete converter design is presented in detailed and characterized in efficiency terms. Both benefits, provided by SiC power devices and by a redesign of the converter layout increased the converter power density up to 2.2 k...

  9. Efficient Implementation of Sample Rate Converter

    OpenAIRE

    Charanjit singh; Manjeet Singh patterh; Sanjay Sharma

    2011-01-01

    Within wireless base station system design, manufacturers continue to seek ways to add value and performance while increasing differentiation. Transmit/receive functionality has become an area of focus as designers attempt to address the need to move data from very high frequency sample rates to chip processing rates. Digital Up Converter (DUC) and Digital Down Converter (DDC) are used as sample rate converters. These are the important block in every digital communication system; hence there ...

  10. Silicon waveguide based TE mode converter.

    Science.gov (United States)

    Zhang, Jing; Liow, Tsung-Yang; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2010-11-22

    A silicon waveguide based TE mode converter was designed for the mode conversion between a horizontal waveguide and vertical waveguide in the two-layer structure waveguide based polarization diversity circuit. The TE mode converter's performance was studied. The polarization mode converter with minimum length of 5 μm was demonstrated to provide the TE mode conversion while maintaining the polarization status. The insertion loss at the transition region was less than 2 dB. PMID:21164874

  11. Ocean floor mounting of wave energy converters

    Science.gov (United States)

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  12. Timing of Convertible Debt Financing and Investment

    OpenAIRE

    Kyoko Yagi; Ryuta Takashima; Hiroshi Takamori; Katsushige Sawaki

    2008-01-01

    In this paper, we examine the optimal investment policy of the firm which is financed by issuing equity, straight debt and convertible debt. We extend the model in Mauer and Sarkar (2005) over financing with convertible debt. We examine two different investment policies that maximize the equity value and the firm value and show the agency cost as the difference between each policy value. Furthermore, we investigate how the issuance of convertible debt affects investment.

  13. Regeneration of ZVS converter with Resonant inductor

    Directory of Open Access Journals (Sweden)

    J.Sivavara Prasad

    2011-09-01

    Full Text Available This paper presents an analysis of the regeneration of zero-voltage-switching converter with resonant inductor, quasi-resonant converters, and full-bridge zero-voltage-switched PWM Converter. The design of a clamping circuit considering a saturable resonant inductor is presented and compared with the design of a clamping circuit with a linear resonant inductor. A diode model with reverse recovery is employed to simulate the effects.

  14. Catalytically powered dynamic assembly of rod-shaped nanomotors and passive tracer particles

    OpenAIRE

    Wang, Wei; Duan, Wentao; Sen, Ayusman; Mallouk, Thomas E.

    2013-01-01

    Microscale catalyst particles suspended in fluids can convert the energy of chemical reactions that occur on their surfaces to movement. Collections of particles undergoing powered motion exhibit behavior that mimics living microparticles such as bacteria: swarming, predator–prey interactions, and chemotaxis. These behaviors originate from pairwise interactions of particles that so far have not been measured or understood. In this article, short-range attractive interactions of catalytic nano...

  15. Commutation Processes in Multiresonant ZVS Bridge Converter

    Directory of Open Access Journals (Sweden)

    Miroslaw Luft

    2008-01-01

    Full Text Available The analysis of the multiresonant ZVS DC/DC bridge converter is presented. The control system of the converter is basedon the method of frequency control at the constant time of transistor turn-off with a phase shift. The operation of the circuit is givenand the operating range of the converter is defined where ZVS switching operation is assured. Control characteristics are given andthe converter’s efficiency is defined. The circuit’s operation is analysed on the basis of results of the converter simulation tests using Simplorer programme.

  16. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes

    Science.gov (United States)

    McMillan, Duncan G. G.; Marritt, Sophie J.; Kemp, Gemma L.; Gordon-Brown, Piers; Butt, Julea N.; Jeuken, Lars J. C.

    2014-01-01

    It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes. PMID:24634538

  17. The Impact of Enzyme Orientation and Electrode Topology on the Catalytic Activity of Adsorbed Redox Enzymes.

    Science.gov (United States)

    McMillan, Duncan G G; Marritt, Sophie J; Kemp, Gemma L; Gordon-Brown, Piers; Butt, Julea N; Jeuken, Lars J C

    2013-11-01

    It is well established that the structural details of electrodes and their interaction with adsorbed enzyme influences the interfacial electron transfer rate. However, for nanostructured electrodes, it is likely that the structure also impacts on substrate flux near the adsorbed enzymes and thus catalytic activity. Furthermore, for enzymes converting macro-molecular substrates it is possible that the enzyme orientation determines the nature of interactions between the adsorbed enzyme and substrate and therefore catalytic rates. In essence the electrode may impede substrate access to the active site of the enzyme. We have tested these possibilities through studies of the catalytic performance of two enzymes adsorbed on topologically distinct electrode materials. Escherichia coli NrfA, a nitrite reductase, was adsorbed on mesoporous, nanocrystalline SnO2 electrodes. CymA from Shewanella oneidensis MR-1 reduces menaquinone-7 within 200 nm sized liposomes and this reaction was studied with the enzyme adsorbed on SAM modified ultra-flat gold electrodes.

  18. Dual-Bed Catalytic System for Direct Conversion of Methane to Liquid Hydrocarbons

    Institute of Scientific and Technical Information of China (English)

    N.A.S.Amin; Sriraj Ammasi

    2006-01-01

    A dual-bed catalytic system is proposed for the direct conversion of methane to liquid hydrocarbons. In this system, methane is converted in the first stage to oxidative coupling of methane (OCM) products by selective catalytic oxidation with oxygen over La-supported MgO catalyst. The second bed, comprising of the HZSM-5 zeolite catalyst, is used for the oligomerization of OCM light hydrocarbon products to liquid hydrocarbons. The effects of temperature (650-800 ℃), methane to oxygen ratio (4-10), and SiO2/Al2O3 ratio of the HZSM-5 zeolite catalyst on the process are studied. At higher reaction temperatures, there is considerable dealumination of HZSM-5, and thus its catalytic performance is reduced. The acidity of HZSM-5 in the second bed is responsible for the oligomerization reaction that leads to the formation of liquid hydrocarbons. The activities of the oligomerization sites were unequivocally affected by the SiO2/Al2O3 ratio. The relation between the acidity and the activity of HZSM-5 is studied by means of TPD-NH3 techniques. The rise in oxygen concentration is not beneficial for the C5+ selectivity, where the combustion reaction of intermediate hydrocarbon products that leads to the formation of carbon oxide (CO+CO2) products is more dominant than the oligomerization reaction. The dual-bed catalytic system is highly potential for directly converting methane to liquid fuels.

  19. Catalytic Fast Pyrolysis: A Review

    Directory of Open Access Journals (Sweden)

    Theodore Dickerson

    2013-01-01

    Full Text Available Catalytic pyrolysis is a promising thermochemical conversion route for lignocellulosic biomass that produces chemicals and fuels compatible with current, petrochemical infrastructure. Catalytic modifications to pyrolysis bio-oils are geared towards the elimination and substitution of oxygen and oxygen-containing functionalities in addition to increasing the hydrogen to carbon ratio of the final products. Recent progress has focused on both hydrodeoxygenation and hydrogenation of bio-oil using a variety of metal catalysts and the production of aromatics from bio-oil using cracking zeolites. Research is currently focused on developing multi-functional catalysts used in situ that benefit from the advantages of both hydrodeoxygenation and zeolite cracking. Development of robust, highly selective catalysts will help achieve the goal of producing drop-in fuels and petrochemical commodities from wood and other lignocellulosic biomass streams. The current paper will examine these developments by means of a review of existing literature.

  20. 车用三元催化转化器快速老化试验研究%Accelerated Aging Tests of Three-way Catalytic Convener on Automotive

    Institute of Scientific and Technical Information of China (English)

    郝宝玉; 侯献军; 彭辅明; 刘华刚; 颜伏伍

    2011-01-01

    根据国内外三元催化转化器老化评价方法,建立了车用催化器快速老化试验装置,并对试验装置进行优化.试验数据表明,三元催化转化器经过100 h老化后CO、HC、NOx的起燃温度分别升高42℃、40℃、30℃,对催化器起燃不利,HC的转化效率显著降低,催化器老化后空燃比特性曲线的高效窗口几乎不复存在,催化器性能趋向恶化.%Based on experiences of auto catalytic converter evaluation method, automotive catalytic converter rapid aging test e-quipment was developed and optimized. Experimental data show that,after three-way catalytic converter being aged,the ignition temperature of CO, HC, Nox, respectively increased by 42℃ ,40℃ ,30℃. The ignition temperature increase performed negative effects on the catalytic converter, and HC significantly reduced the conversion efficiency of catalytic device. The efficient window of air -fuel ratio curve had almost disappeared after catalytic converter aged,and catalyst performance deteriorated.

  1. Thermodynamics of catalytic nanoparticle morphology

    Science.gov (United States)

    Zwolak, Michael; Sharma, Renu; Lin, Pin Ann

    Metallic nanoparticles are an important class of industrial catalysts. The variability of their properties and the environment in which they act, from their chemical nature & surface modification to their dispersion and support, allows their performance to be optimized for many chemical processes useful in, e.g., energy applications and other areas. Their large surface area to volume ratio, as well as varying sizes and faceting, in particular, makes them an efficient source for catalytically active sites. These characteristics of nanoparticles - i.e., their morphology - can often display intriguing behavior as a catalytic process progresses. We develop a thermodynamic model of nanoparticle morphology, one that captures the competition of surface energy with other interactions, to predict structural changes during catalytic processes. Comparing the model to environmental transmission electron microscope images of nickel nanoparticles during carbon nanotube (and other product) growth demonstrates that nickel deformation in response to the nanotube growth is due to a favorable interaction with carbon. Moreover, this deformation is halted due to insufficient volume of the particles. We will discuss the factors that influence morphology and also how the model can be used to extract interaction strengths from experimental observations.

  2. Feasibility of converting lactic acid to ethanol in food waste fermentation by immobilized lactate oxidase

    International Nuclear Information System (INIS)

    Highlights: • Residue lactic acid in food waste could be converted to pyruvic acid. • Calcium alginate immobilized the lactate oxidase with high pH and thermal stability. • Immobilized enzyme could convert 70% lactic acid to pyruvic acid. • Ethanol yield could be increased by 20% with lactate oxidase added. - Abstract: Adoption of lactic acid bacteria (LAB) into ethanol fermentation from food waste can replace the sterilization process. However, LAB inoculation will convert part of the substrate into lactic acid (LA), not ethanol. This study adopted lactate oxidase to convert the produced LA to pyruvate, and then ethanol fermentation was carried out. The immobilization enzyme was utilized, and corresponding optimum conditions were determined. Results showed that calcium alginate could successfully immobilize the enzyme and improve pH and thermal stability. The optimum pH and temperature were 6.2 and 55 °C, respectively. The utilization of immobilized enzyme with catalytic time of 5 h could convert 70% LA to pyruvate, and the addition of enzyme increased the ethanol yield by 20% more than that of the control. The process could be applied in food waste storage and can help in reducing carbon source consumption

  3. Passive Resonant Bidirectional Converter with Galvanic Barrier

    Science.gov (United States)

    Rosenblad, Nathan S. (Inventor)

    2014-01-01

    A passive resonant bidirectional converter system that transports energy across a galvanic barrier includes a converter using at least first and second converter sections, each section including a pair of transfer terminals, a center tapped winding; a chopper circuit interconnected between the center tapped winding and one of the transfer terminals; an inductance feed winding interconnected between the other of the transfer terminals and the center tap and a resonant tank circuit including at least the inductance of the center tap winding and the parasitic capacitance of the chopper circuit for operating the converter section at resonance; the center tapped windings of the first and second converter sections being disposed on a first common winding core and the inductance feed windings of the first and second converter sections being disposed on a second common winding core for automatically synchronizing the resonant oscillation of the first and second converter sections and transferring energy between the converter sections until the voltage across the pairs of transfer terminals achieves the turns ratio of the center tapped windings.

  4. Multilevel converters for 10 MW Wind Turbines

    DEFF Research Database (Denmark)

    Ma, Ke; Blaabjerg, Frede

    2011-01-01

    Several promising multi-level converter configurations for 10 MW Wind Turbines both with direct drive and one-stage gear box drive using Permanent Magnet Synchronous Generator (PMSG) are proposed, designed and compared. Reliability is a crucial indicator for large scale wind power converters...

  5. Power Converters Secure Electronics in Harsh Environments

    Science.gov (United States)

    2013-01-01

    In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

  6. Switched-mode converters (one quadrant)

    CERN Document Server

    Barrade, P

    2006-01-01

    Switched-mode converters are DC/DC converters that supply DC loads with a regulated output voltage, and protection against overcurrents and short circuits. These converters are generally fed from an AC network via a transformer and a conventional diode rectifier. Switched-mode converters (one quadrant) are non-reversible converters that allow the feeding of a DC load with unipolar voltage and current. The switched-mode converters presented in this contribution are classified into two families. The first is dedicated to the basic topologies of DC/DC converters, generally used for low- to mid-power applications. As such structures enable only hard commutation processes, the main drawback of such topologies is high commutation losses. A typical multichannel evolution is presented that allows an interesting decrease in these losses. Deduced from this direct DC/DC converter, an evolution is also presented that allows the integration of a transformer into the buck and the buck–boost structure. This enables an int...

  7. Modeling and Simulation of Matrix Converter

    DEFF Research Database (Denmark)

    Liu, Fu-rong; Klumpner, Christian; Blaabjerg, Frede

    2005-01-01

    This paper discusses the modeling and simulation of matrix converter. Two models of matrix converter are presented: one is based on indirect space vector modulation and the other is based on power balance equation. The basis of these two models is• given and the process on modeling is introduced in...

  8. High Precision Current Measurement for Power Converters

    CERN Document Server

    Cerqueira Bastos, M

    2015-01-01

    The accurate measurement of power converter currents is essential to controlling and delivering stable and repeatable currents to magnets in particle accelerators. This paper reviews the most commonly used devices for the measurement of power converter currents and discusses test and calibration methods.

  9. High Precision Current Measurement for Power Converters

    OpenAIRE

    Bastos, M. Cerqueira

    2016-01-01

    The accurate measurement of power converter currents is essential to controlling and delivering stable and repeatable currents to magnets in particle accelerators. This paper reviews the most commonly used devices for the measurement of power converter currents and discusses test and calibration methods.

  10. Selective harmonic control for power converters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede;

    2014-01-01

    This paper proposes an Internal Model Principle (IMP) based Selective Harmonic Controller (SHC) for power converters. The proposed SHC offers an optimal control solution for power converters to mitigate power harmonics. It makes a good trade-off among cost, complexity and performance. It has high...

  11. Present trends in HVDC converter station design

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Lennart; Asplund, Gunnar; Bjorklund, Hans; Flisberg, Gunnar [ABB Power Systems AB, Ludvika (Sweden)

    1994-12-31

    HVDC converter station technology has developed rapidly to satisfy increasing requirements during past 10 - 15 years, but there has not been any dramatic changes since thyristor valves were introduced in the mid 70s. This paper describes some recent and expected future developments, that will substantiality change and simplify future converter stations. (author) 4 refs., 7 figs.

  12. Catalytic Gasification of Lignocellulosic Biomass

    NARCIS (Netherlands)

    Chodimella, V.P.; Seshan, K.; Schlaf, Marcel; Zhang, Z. Conrad

    2015-01-01

    Gasification of lignocellulosic biomass has attracted substantial current research interest. Various possible routes to convert biomass to fuels have been explored. In the present chapter, an overview of the gasification processes and their possible products are discussed. Gasification of solid biom

  13. Radiation Effects on DC-DC Converters

    Science.gov (United States)

    Zhang, De-Xin; AbdulMazid, M. D.; Attia, John O.; Kankam, Mark D. (Technical Monitor)

    2001-01-01

    In this work, several DC-DC converters were designed and built. The converters are Buck Buck-Boost, Cuk, Flyback, and full-bridge zero-voltage switched. The total ionizing dose radiation and single event effects on the converters were investigated. The experimental results for the TID effects tests show that the voltages of the Buck Buck-Boost, Cuk, and Flyback converters increase as total dose increased when using power MOSFET IRF250 as a switching transistor. The change in output voltage with total dose is highest for the Buck converter and the lowest for Flyback converter. The trend of increase in output voltages with total dose in the present work agrees with those of the literature. The trends of the experimental results also agree with those obtained from PSPICE simulation. For the full-bridge zero-voltage switch converter, it was observed that the dc-dc converter with IRF250 power MOSFET did not show a significant change of output voltage with total dose. In addition, for the dc-dc converter with FSF254R4 radiation-hardened power MOSFET, the output voltage did not change significantly with total dose. The experimental results were confirmed by PSPICE simulation that showed that FB-ZVS converter with IRF250 power MOSFET's was not affected with the increase in total ionizing dose. Single Event Effects (SEE) radiation tests were performed on FB-ZVS converters. It was observed that the FB-ZVS converter with the IRF250 power MOSFET, when the device was irradiated with Krypton ion with ion-energy of 150 MeV and LET of 41.3 MeV-square cm/mg, the output voltage increased with the increase in fluence. However, for Krypton with ion-energy of 600 MeV and LET of 33.65 MeV-square cm/mg, and two out of four transistors of the converter were permanently damaged. The dc-dc converter with FSF254R4 radiation hardened power MOSFET's did not show significant change at the output voltage with fluence while being irradiated by Krypton with ion energy of 1.20 GeV and LET of 25

  14. SPECTRAL ANALYSIS OF BUCK AND SEPIC CONVERTERS

    Directory of Open Access Journals (Sweden)

    CHAKIB ALAOUI

    2011-02-01

    Full Text Available Switched mode power converters generate harmonic currents, which will be injected into the utility grid, causing distortion of the utility waveform. They also become a source for the generation of EMI, which may affect the communication systems. This work is about the design and evaluation of the two most frequently used SMPS used in step down mode of operation: the Buck converter and the Sepic converter working in step-down mode of operation. These converters were designed using optimized equations for their components ratings. Simulation results show that although the Buck output voltage is low in harmonics, it has high harmonic contents in currents circulating in its inductor and diode, and hence requires strong filtering. The Sepic converterhas lower harmonic contents than the Buck converter.

  15. Switched Mode Four-Quadrant Converters

    CERN Document Server

    Thurel, Y

    2015-01-01

    This paper was originally presented at CAS-2004, and was slightly modified for CAS-2014. It presents a review of the key parameters that impact the design choices for a true four-quadrant power converter, in the range 1-10 kW, mainly based on switching mode converter topology. This paper will first describe the state-of-the-art for this power converter family, giving the drawbacks and advantages of different possible solutions. It will also present practical results obtained from the CERN-designed converter. It will finally give some important tips regarding critical phases like test one, when conducting a project dealing with this type of power converter.

  16. Reliability of Power Electronic Converter Systems

    DEFF Research Database (Denmark)

    The main aims of power electronic converter systems (PECS) are to control, convert, and condition electrical power flow from one form to another through the use of solid-state electronics. This book outlines current research into the scientific modeling, experimentation, and remedial measures...... electronic converter systems; anomaly detection and remaining-life prediction for power electronics; reliability of DC-link capacitors in power electronic converters; reliability of power electronics packaging; modeling for life-time prediction of power semiconductor modules; minimization of DC......-link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault...

  17. PERFORMANCE ANALYSIS OF 2D CONVERTER BY COMBINING SR & KY CONVERTERS

    Directory of Open Access Journals (Sweden)

    V. Manoj Kumar

    2014-03-01

    Full Text Available Most of the portable equipments use battery as power source. The increasing use of low voltage portable devices and growing requirements of functionalities embedded into such devices. Thus an efficient power management technique is needed for longer battery life for them. Highly variable nature of batteries systems often require supply voltages to be both higher and lower than the battery. This is most efficiently generated by a buck-boost switching converter. But here the converter efficiency is decreased since the power loss occurs in the storage devices. Step by step, process of designing, feedback control and simulation of a novel voltage-buck boost converter, combining KY and synchronous Rectifier buck converter for battery power applications. Unlike the traditional buck–boost converter, this converter has the positive output voltage and system is stable, different from the negative output voltage and low stable of the traditional inverting buck–boost converters. Since such a converter operates in continuous conduction mode. Also it possesses the non-pulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Both the KY converter and the synchronous buck converter, combined into a positive buck– boost converter, uses the same power switches. Here it makes the circuit to be compact and the corresponding cost to be down. Voltage conversion ratio is 2D,so it is also called 2D converter.

  18. Boost matrix converters in clean energy systems

    Science.gov (United States)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  19. Electromagnetic Compatibility of Matrix Converter System

    Directory of Open Access Journals (Sweden)

    S. Fligl

    2006-12-01

    Full Text Available The presented paper deals with matrix converters pulse width modulation strategies design with emphasis on the electromagnetic compatibility. Matrix converters provide an all-silicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer. They possess many advantages compared to the conventional voltage or current source inverters. A matrix converter does not require energy storage components as a bulky capacitor or an inductance in the DC-link, and enables the bi-directional power flow between the power supply and load. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics, and to control the input displacement factor. The perspective of matrix converters regarding EMC in comparison with other types of converters is brightly evident because it is no need to use any equipment for power factor correction and current and voltage harmonics reduction. Such converter with proper control is properly compatible both with the supply mains and with the supplied load. A special digital control system was developed for the realized experimental test bed which makes it possible to achieve greater throughput of the digital control system and its variability.

  20. Reduction of greenhouse gas emissions by catalytic processes

    International Nuclear Information System (INIS)

    Catalytic technologies for the abatement of greenhouse gases (GGs) can be an effective possibility for limiting the increasing tropospheric concentration of GGs and reducing their contribution to global warming. Two different cases are discussed: (1) reduction of anthropogenic emissions of non-CO2 GGs (N2O and CH4) and (2) reduction or conversion of CO2. In methane conversion waste gases containing diluted methane can be converted at low temperature using Pd supported on titania-ceria catalysts which show also a good resistance to deactivation. Rh supported on modified zirconia-alumina catalysts are effective and stable catalysts in low temperature decomposition of N2O. The concept of reduction of CO2 back to fuels in a photo-electrocatalytic reactor is also presented

  1. Studies on Catalytic Pyrolysis of Daqing Atmospheric Residue

    Institute of Scientific and Technical Information of China (English)

    孟祥海; 徐春明; 张倩; 高金森

    2004-01-01

    Catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 was investigated in a confined fluidized bed reactor. The results show that reaction temperature, the mass ratios of catalyst to oil and steam to oil have significant effects on product distribution and yields of light olefins. The yields of light olefins show the maxima with the increase of reaction temperature, the mass ratios of catalyst to oil and steam to oil, respectively. The optimized operating conditions were determined in the laboratory, and under that condition the yields of ethylene, propylene and total light olefins by mass were 15.9%, 20.7% and 44.3% respectively. The analysis of pyrolysis gas and pyrolysis liquid indicates that CEP-1 has good capacity of converting heavy oils into light olefins, and there is a large amount of aromatics in pyrolysis liquid.

  2. Ex-Situ Catalytic Fast Pyrolysis Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, Mary J.; Dutta, Abhijit; Jones, Susanne B.; Meyer, Pimphan A.

    2013-03-31

    In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to hydrocarbon fuels to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This pathway case investigates converting woody biomass using ex-situ catalytic fast pyrolysis followed by upgrading to gasoline , diesel and jet range blendstocks . Technical barriers and key research needs that should be pursued for this pathway to be competitive with petroleum-derived blendstocks have been identified.

  3. In-Situ Catalytic Fast Pyrolysis Technology Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Biddy, Mary J.; Dutta, Abhijit; Jones, Susanne B.; Meyer, Pimphan A.

    2013-03-31

    In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to hydrocarbon fuels to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This pathway case investigates converting woody biomass using in-situ catalytic fast pyrolysis followed by upgrading to gasoline, diesel, and jet range blendstocks. Technical barriers and key research needs that should be pursued for this pathway to be competitive with petroleum-derived blendstocks have been identified.

  4. Catalytic conversion of methane: Carbon dioxide reforming and oxidative coupling

    KAUST Repository

    Takanabe, Kazuhiro

    2012-01-01

    Natural gas conversion remains one of the essential technologies for current energy needs. This review focuses on the mechanistic aspects of the development of efficient and durable catalysts for two reactions, carbon dioxide reforming and the oxidative coupling of methane. These two reactions have tremendous technological significance for practical application in industry. An understanding of the fundamental aspects and reaction mechanisms of the catalytic reactions reviewed in this study would support the design of industrial catalysts. CO 2 reforming of methane utilizes CO 2, which is often stored in large quantities, to convert as a reactant. Strategies to eliminate carbon deposition, which is the major problem associated with this reaction, are discussed. The oxidative coupling of methane directly produces ethylene in one reactor through a slightly exothermic reaction, potentially minimizing the capital cost of the natural gas conversion process. The focus of discussion in this review will be on the attainable yield of C 2 products by rigorous kinetic analyses.

  5. Propagation characteristics of converted refracted wave and its application in static correction of converted wave

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Three-component seismic exploration through P-wave source and three-component geophone is an effective technique used in complicated reservoir exploration. In three-component seismic exploration data processing,one of the difficulties is static correction of converted wave. This paper analyzes propagation characteristics of non-converted and converted refracted waves,and discovers a favor-able condition for the formation of converted refracted wave,i.e. the velocity of overlaying medium S wave is much lower than that of underlying medium S wave. In addition,the paper proposes the static correction method of converted wave based on PPS converted refracted wave,and processes the real three-component seismic data with better results of static correction of converted wave.

  6. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  7. Application of AGPU for Matrix Converters

    Directory of Open Access Journals (Sweden)

    Nithin T Abraham

    2014-07-01

    Full Text Available A simple PI control loop for the matrix converter system is designed in the simulation to maintain a constant output voltage inspite of any disturbance in the source. The single phase matrix converter employs a modified safe-commutation strategy, which results in the elimination of voltage spikes on switches, without the need of a snubber circuit when there is an inductive load being utilized. This is facilitated through the proper switching control algorithm. The sine PWM pulses are generated as switching pulses to the converter to reduce the THD.

  8. Matrix laser IR-visible image converter

    International Nuclear Information System (INIS)

    A new type of a focal matrix IR-visible image converter is proposed. The pixel IR detectors of the matrix are tunable microcavities of VCSEL (vertical-cavity surface emitting laser) semiconductor microstructures. The image conversion is performed due to the displacements of highly reflecting cavity mirrors caused by thermoelastic stresses in their microsuspensions appearing upon absorption of IR radiation. Analysis of the possibilities of the converter shows that its sensitivity is 10-3-10-2 K and the time response is 10-4-10-3 s. These characteristics determine the practical application of the converter. (laser applications and other topics in quantum electronics)

  9. Data Converter for Multistandard Mobile Phones

    DEFF Research Database (Denmark)

    Yurttas, Aziz; Bruun, Erik; Jensen, Rasmus Glarborg

    2004-01-01

    This paper describes an analog to digital converter (ADC) for mobile communication systems using a direct down conversion architecture. The ADC can be programmed to meet the requirements of different communication standards, including GSM (Global System for Mobile communication) and WCDMA (Wideband...... Code Division Multiple Access). The ADC is realized with a pipeline ADC architecture for WCDMA and a Sigma-Delta architecture for GSM. In order to have an optimized area and power consumption, the basic building blocks (opamps) of the converters are shared between the two converter architectures...

  10. Spectral Analysis of Sample Rate Converter

    Directory of Open Access Journals (Sweden)

    Manish Sabraj

    2010-10-01

    Full Text Available The aim of digital sample rate conversion is to bring a digital audio signal from one sample frequency to another. The distortion of the audio signal introduced by the sample rate converter should be as low as possible. The generation of the output samples from the input samples may be performed by the application of various methods. In this paper, a new technique of digital sample-rate converter is proposed. We perform the spectral analysis of proposed digital sample rate converter.

  11. Converters for Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Yang, Yongheng

    2015-01-01

    presents an overview of the power converters for the DPGS, mainly based on wind turbine systems and photovoltaic systems, covering a wide range of applications. Moreover, the modulation schemes and interfacing power filters for the power converters are also exemplified. Finally, the general control......Power electronics technology has become the enabling technology for the integration of distributed power generation systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...

  12. Computational Introduction of Catalytic Activity into Proteins.

    Science.gov (United States)

    Bertolani, Steve J; Carlin, Dylan Alexander; Siegel, Justin B

    2016-01-01

    Recently, there have been several successful cases of introducing catalytic activity into proteins. One method that has been used successfully to achieve this is the theozyme placement and enzyme design algorithms implemented in Rosetta Molecular Modeling Suite. Here, we illustrate how to use this software to recapitulate the placement of catalytic residues and ligand into a protein using a theozyme, protein scaffold, and catalytic constraints as input. PMID:27094294

  13. Some Aspects of the Catalytic Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    Anil; K.Saikia

    2007-01-01

    1 Results Catalytic reactions are gaining importance due to its low cost, operational simplicity, high efficiency and selectivity. It is also getting much attention in green synthesis. Many useful organic reactions, including the acylation of alcohols and aldehydes, carbon-carbon, carbon-nitrogen, carbon-sulfur bond forming and oxidation reactions are carried out by catalyst. We are exploring the catalytic acylation of alcohols and aldehydes in a simple and efficient manner. Catalytic activation of unr...

  14. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  15. Nanostructured Catalytic Reactors for Air Purification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II project proposes the development of lightweight compact nanostructured catalytic reactors for air purification from toxic gaseous organic...

  16. From waste to energy -- Catalytic steam gasification of broiler litter

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.A.; Sheth, A.C.

    1999-07-01

    In 1996, the production of broiler chickens in the US was approximately 7.60 billion head. The quantity of litter generated is enormous. In 1992, the Southeast region alone produced over five million tons of broiler litter. The litter removed from the broiler houses is rich in nutrients and often spread over land as a fertilizer. Without careful management, the associated agricultural runoff can cause severe environmental damage. With increasing broiler litter production, the implementation of alternative disposal technologies is essential to the sustainable development of the poultry industry. A process originally developed for the conversion of coals to clean gaseous fuel may provide an answer. Catalytic steam gasification utilities an alkali salt catalyst and steam to convert a carbonaceous feedstock to a gas mixture composed primarily of carbon monoxide, carbon dioxide, hydrogen, and methane. The low to medium energy content gas produced may be utilized as an energy source or chemical feedstock. Broiler litter is an attractive candidate for catalytic steam gasification due to its high potassium content. Experiments conducted in UTSI's bench-scale high-pressure fixed bed gasifier have provided data for technical and economic feasibility studies of the process. Experiments have also been performed to examine the effects of temperature, pressure, and additional catalysts on the gasification rate.

  17. Catalytic hydrolysis for the degradation of organophosphorus pesticides in water

    International Nuclear Information System (INIS)

    The kinetic studies of catalytic hydrolysis revealed that the concentration of two kinds of organophosphorus pesticides (omethoate and methidathion) in solution apparently decays according to the second order reaction. It was found that the rate constant value was highest at strong acidic conditions and it continued to decrease as the pH of the solution was increased. At basic conditions the rate constant value decreased to minimum. Manganese dioxide under acidic conditions converted into Mn/sup 2+/ ions and then these ions in water form hexaaquomanganese (II) ion. This hexaaquomanganese (II ion then adsorbed itself on the S or O atom of the organophosphorus compound and thus weakens the bond between P-S. This reaction facilitated the attack of H/sub 2/O or OH/sup -/ ion and thus enhanced the efficiency of hydrolysis. It was studied that methidathion hydrolyzed more efficiently than omethoate The rate constants of catalytic hydrolysis were increased with increasing the amount of MnO/sub 2/. It was found that the pesticides had undergone adsorption on catalyst in the first few minutes and there was the rapid drop of total phosphorus concentration. The decrease of total phosphorus adsorption with increasing pH was also observed. After the addition of alkaline earth metal cations (Ca/sup 2+/ and Mg/sup 2+/) along with magnesium, the enhancement in the efficiency of hydrolysis at near neutral conditions occurred. (author)

  18. Metal Chlorides in Ionic Liquid Solvents Convert Sugars to 5-Hydroxymethylfurfural

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haibo; Holladay, John E.; Brown, Heather M.; Zhang, Z. Conrad

    2007-06-15

    Sugars were converted to hydroxymethylfurfural (HMF) at high yield in ionic liquids without the addition of Bronsted acids. Very small amount of certain metal halides significantly reduced the fructose dehydration barrier in ionic liquids producing HMF at high yields. Most remarkably, glucose, a common sugar molecule, was selectively converted to HMF in good yield in ionic liquids containing a small amount of CrCl2. Thus CrCl2 is unique among metal chlorides tested for its effectiveness in both isomerizing glucose as well as dehydrating fructose. Only negligble amount of levulinic acid was formed in the reactions. The catalytic activity of metal chlorides for sugar conversion in ionic liquids is perhaps related to hydroxyl group of the sugar forming metal complexes with the unsaturated metal center.

  19. Catalytic reforming feed characterisation technique

    Energy Technology Data Exchange (ETDEWEB)

    Larraz Mora, R.; Arvelo Alvarez, R. [Univ. of La Laguna, Chemical Engineering Dept., La Laguna (Spain)

    2002-09-01

    The catalytic reforming of naphtha is one of the major refinery processes, designed to increase the octane number of naphtha or to produce aromatics. The naphtha used as catalytic reformer feedstock usually contains a mixture of paraffins, naphthenes, and aromatics in the carbon number range C{sub 6} to C{sub 10}. The detailed chemical composition of the feed is necessary to predict the aromatics and hydrogen production as well as the operation severity. The analysis of feed naphtha is usually reported in terms of its ASTM distillation curve and API or specific gravity. Since reforming reactions are described in terms of lumped chemical species (paraffins, naphthenes and aromatics), a feed characterisation technique should be useful in order to predict reforming operating conditions and detect feed quality changes. Unfortunately online analyzer applications as cromatography or recently introduced naphtha NMR [1] are scarce in most of refineries. This work proposes an algorithmic characterisation method focusing on its main steps description. The method could help on the subjects previously described, finally a calculation example is shown. (orig.)

  20. Reliability of power electronic converter systems

    CERN Document Server

    Chung, Henry Shu-hung; Blaabjerg, Frede; Pecht, Michael

    2016-01-01

    This book outlines current research into the scientific modeling, experimentation, and remedial measures for advancing the reliability, availability, system robustness, and maintainability of Power Electronic Converter Systems (PECS) at different levels of complexity.

  1. Energy saving dc-dc converter circuit

    International Nuclear Information System (INIS)

    An energy saving dc-dc converter circuit is disclosed having two energy efficient means which operate in tandem, an energy conserving means and a voltage doubling means. These energy efficient means are applied in combination with elements commonly found in dc-dc converter circuits, namely an ac voltage generator, a transformer for stepping up the generated ac voltage, and means for storing the converted dc voltage. The energy conserving means is connected to the dc voltage storage means. It comprises a resettable inhibit circuit which cuts off the provision of dc voltage for conversion for a predetermined interval when the output of the converter exceeds a predetermined level. The voltage doubling means is reponsive to outputs of the inhibit circuit of the energy conserving means and the ac voltage generator. It provides a phase inverted waveform of the generated ac voltage on one of two leads to the ac voltage step-up transformer

  2. Input-output rearrangement of isolated converters

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Kovacevic, Milovan; Mønster, Jakob Døllner;

    2015-01-01

    This paper presents a new way of rearranging the input and output of isolated converters. The new arrangement posses several advantages, as increased voltage range, higher power handling capabilities, reduced voltage stress and improved efficiency, for applications where galvanic isolation...

  3. Interface of magnetoresistive converter of active power

    Directory of Open Access Journals (Sweden)

    A. I. Vytiaganets

    2009-10-01

    Full Text Available The vehicle and programmatic interfaces of magnetoresistive converter of active power are considered, the results of statistical treatment of the multiple measuring of active-power are analysed.

  4. Converter station of Juebek; Umrichterwerk Juebek

    Energy Technology Data Exchange (ETDEWEB)

    Zimmert, G. [AEG Bahnfahrwegsysteme GmbH, Frankfurt am Main (Germany); Scheuring, J. [AEG Bahnfahrwegsysteme GmbH, Frankfurt am Main (Germany); Werth, L. [AEG Bahnfahrwegsysteme GmbH, Frankfurt am Main (Germany); Koeltzsch, W. [Deutsche Bahn AG, Hamburg (Germany); Niehage, H. [AEG Anlagen- und Antriebssysteme GmbH, Berlin (Germany); Tadros, Y. [Daimler Benz AG, Berlin (Germany). Forschungsinstitut fuer Antriebstechnik und Leistungselektronik

    1995-09-01

    Most northern electrified lines in Schleswig-Holstein will be supplied with a.c. 16 2/3 Hz 15 kV traction energy from de-central converter station of Juebek which is under construction as a turn-key project. Converter technology based on semiconductor power elements will replace the conventional technology of rotating converters in the future. The paper gives a survey about importance and conception of Juebek converter station, incorporated technology and its state of construction. (orig.) [Deutsch] Zur Bahnenergieversorgung des noerdlichsten Bereiches der elektrifizierten Strecken in Schleswig-Holstein mit AC 16 2/3 Hz 15 kV wird zur Zeit das dezentrale Umrichterwerk Juebek als schluesselfertige Anlage errichtet. Die Umrichtertechnik auf der Basis leistungselektronischer Stromrichter wird in den kommenden Jahren die bisherige Maschinenumformertechnik abloesen. Der Beitrag gibt einen Ueberblick ueber die Bedeutung und das Konzept des Umrichterwerkes Juebek, die eingesetzte Technik und den Stand des Bauablaufes. (orig.)

  5. Three-phase Resonant DC-link Converter

    DEFF Research Database (Denmark)

    Munk-Nielsen, Stig

    The purpose of the project is to develop a three-phase resonant converter suitable for standard speed drives. The motivation for working with resonant converters is found in the problem of the standard converter type used today. In standard converter type Pulse Width Modulated-Voltage Source...... frequency three phase parallel resonant converter is realized....

  6. A Multiport Isolated DC-DC Converter

    OpenAIRE

    Tran, Yan-Kim; Dujic, Drazen

    2016-01-01

    This paper presents a multi-port isolated DC-DC converter for DC applications. A three-port structure is presented, characterized with full bidirectional power flow and simple control. Galvanic isolation is achieved by means of a multi-winding medium frequency transformer which is a part of a resonant LLC converter. To provide controllable power exchange with external DC ports, two out of three ports are equipped with additional bidirectional buck/boost stages. They serve to provide active po...

  7. AC – AC Converters for UPS

    Directory of Open Access Journals (Sweden)

    Rusalin Lucian R. Păun

    2008-05-01

    Full Text Available This paper propose a new control technique forsingle – phase AC – AC converters used for a on-line UPSwith a good dynamic response, a reduced-partscomponents, a good output characteristic, a good powerfactorcorrection(PFC. This converter no needs anisolation transformer. A power factor correction rectifierand an inverter with the proposed control scheme has beendesigned and simulated using Caspoc2007, validating theconcept.

  8. Torus bifurcations in multilevel converter systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Yanochkina, Olga O.

    2011-01-01

    This paper considers the processes of torus formation and reconstruction through smooth and nonsmooth bifurcations in a pulse-width modulated DC/DC converter with multilevel control. When operating in a regime of high corrector gain, converters of this type can generate structures of stable tori....... The paper also demonstrates how pairs of attracting and repelling tori emerge through border-collision torus-birth and border-collision torus-fold bifurcations. © 2011 World Scientific Publishing Company....

  9. Mathematical efficiency modeling of static power converters

    OpenAIRE

    Hoff Dupont, Fabrício; Zaragoza Bertomeu, Jordi; Rech, Cassiano; Pinheiro, José Renes

    2015-01-01

    This paper presents a review and a comparative analysis between mathematical models for the efficiency of power converters. Two different types of models are considered, being one for converters subject solely for output power variations, and a second one also considering input voltage variations. Both cases are particularly important for systems fed by renewable sources as photovoltaic panels or wind turbines. Knowledge of the appropriate models is of interest in the dev...

  10. Resonant Wave Energy Converters: Concept development

    International Nuclear Information System (INIS)

    The Resonant Wave Energy Converter (REWEC) is a device for converting sea wave energy to electrical energy. It belongs to the family of Oscillating Water Columns and is composed by an absorbing chamber connected to the open sea via a vertical duct. The paper gives a holistic view on the concept development of the device, starting from its implementation in the context of submerged breakwaters to the recently developed vertical breakwaters.

  11. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  12. Effects of electric current upon catalytic steam reforming of biomass gasification tar model compounds to syngas

    International Nuclear Information System (INIS)

    Highlights: • ECR technique was proposed to convert biomass gasification tar model compounds. • Electric current enhanced the reforming efficiency remarkably. • The highest toluene conversion reached 99.9%. • Ni–CeO2/γ-Al2O3 exhibited good stability during the ECR performance. - Abstract: Electrochemical catalytic reforming (ECR) technique, known as electric current enhanced catalytic reforming technique, was proposed to convert the biomass gasification tar into syngas. In this study, Ni–CeO2/γ-Al2O3 catalyst was prepared, and toluene was employed as the major feedstock for ECR experiments using a fixed-bed lab-scale setup where thermal electrons could be generated and provided to the catalyst. Several factors, including the electric current intensity, reaction temperature and steam/carbon (S/C) ratio, were investigated to reveal their effects on the conversion of toluene as well as the composition of the gas products. Moreover, toluene, two other tar model compounds (benzene and 1-methylnaphthalene) and real tar (tar-containing wastewater) were subjected to the long period catalytic stability tests. All the used catalysts were analyzed to determine their carbon contents. The results indicated that the presence of electric current enhanced the catalytic performance remarkably. The toluene conversion reached 99.9% under the electric current of 4 A, catalytic temperature of 800 °C and S/C ratio of 3. Stable conversion performances of benzene, 1-methylnaphthalene and tar-containing wastewater were also observed in the ECR process. H2 and CO were the major gas products, while CO2 and CH4 were the minor ones. Due to the promising capability, the ECR technique deserves further investigation and application for efficient tar conversion

  13. Design of fission neutron converter in HFETR

    International Nuclear Information System (INIS)

    In order to increase local fast neutron fluence rate in High Flux Engineering Test Reactor (HFETR), the fission neutron converter adopted the crisscross fuel rod whose fuel pellet was made of high fission density alloy UMo with 7% Mo. 62 fuel rods in the converter were arranged with triangle dot-matrix between outer tube with diameter of 6.3 mm and inner tube with diameter of 24 mm. And the converter has an irradiation hole with diameter of 20 mm in the center. The calculation result with MCNP shows that fast neutron (E>1 MeV) fluence rate of irradiated samples in the converter can achieve up to 3.34 × 1014 cm-2·s-1, which is about 40% higher than that in the HFETR core at the same position without converter. On the other hand, under the condition of design flow velocity and pressure, the analysis results with ANSYS/CFX show that the maximum permission power can reach 2.4 MW and the maximum power density of fuel pellet is S. 007 kW/cm3. Here, the cladding temperature of the fuel rod is 193.6 ℃, and the converter can fulfill the requirement of thermal-hydraulic design criteria of HFETR and flow instability will not occur. (authors)

  14. LHC Power Converters: A Precision Game

    CERN Multimedia

    2001-01-01

    The LHC test-bed, String 2, is close to commissioning and one important element to get a first chance to prove what it can do is the power converter system. In String 2 there are 16 converters, in the full LHC there will be almost 1800. This article takes a look at what is so special about the power converters for the LHC. The 13 000 Amps power converters with the watercooled cables going to the String 2 feedboxes. The LHC's superconducting magnets will be the pinnacle of high technology. But to work, they'll need the help of high-precision power converters to supply them with extremely stable DC current. Perfection will be the name of the game, with an accuracy of just 1-2 parts per million (ppm) required. LEP, for the sake of comparison, could live with 10-20 ppm. The LHC's power converters will be very different from those of LEP or the SPS since the new accelerator's magnets are mostly superconducting. That means that they require much higher currents at a lower voltage since superconductors have no re...

  15. Performance and Analysis of Modular Multilevel Converter

    Directory of Open Access Journals (Sweden)

    T.Yuvaraja

    2016-07-01

    Full Text Available The Modular Multilevel Converter (MMC represents an emerging topology with a scalable technology making high voltage and power capability possible. The MMC is built up by identical, but individually controllable sub modules. The Modular Multilevel Converter (MMC is a new topology for multilevel converters with potential for medium voltage and high voltage applications. Equivalent Circuit models and dynamic models for the MMC that provide a faithful representation of system behavior are quite complex given the large number of energy states and control variables. They are not particularly useful in studying the terminal behavior of the converter and for the development of an intuitive control approach to regulate power transfer. A control scheme with a new sub module capacitor voltage balancing method is also proposed in this paper. Modular multilevel converters, based on cascading of half bridge converter cells, can combine low switching frequency with low harmonic interference. They can be designed for high operating voltages without direct series connection of semiconductor element

  16. Simulation of Multi output Fly back Converter with Integrated Auxiliary Buck Converter with reduced components

    Directory of Open Access Journals (Sweden)

    J.KOMATHI

    2015-04-01

    Full Text Available The fly back converter has been widely used for multi outputs due to the simple structure and low cost in low-power applications. This paper presents a new multi output converter. It consists of a half-bridge inverter with boost converter in primary side and a fly back rectifier that is integrated with an auxiliary buck converter in secondary side. The boost converter is used to generate high voltage dc from Low voltage PV cells. The primary switches control the main output voltage and the secondary synchronous switches control the auxiliary output voltage. The main advantages of the proposed converter are that the transformer size can be reduced due to the less magnetizing offset current, all the power switches including synchronous ones can achieve the zero-voltage switching (ZVS and it has no output cross regulation problems. The circuit is simulated using MATLAB. The performance is verified with simulation results.

  17. Understanding catalytic biomass conversion through data mining

    NARCIS (Netherlands)

    E.J. Ras; B. McKay; G. Rothenberg

    2010-01-01

    Catalytic conversion of biomass is a key challenge that we chemists face in the twenty-first century. Worldwide, research is conducted into obtaining bulk chemicals, polymers and fuels. Our project centres on glucose valorisation via furfural derivatives using catalytic hydrogenation. We present her

  18. Dual Converter Fed Open-End Transformer Topology with Parallel Converters and Integrated Magnetics

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;

    2016-01-01

    converter group comprises of two parallel Voltage Source Converters (VSCs), whose carrier signals are interleaved to improve the harmonic quality of the resultant switched output voltage of that converter group. However, an additional inductive component is required to suppress the circulating current...... procedure is also described. The volume and the losses of the proposed solution are compared with that of the state-of-art solution. The control of the proposed converter system is also discussed. The analysis has been verified by the simulation and experimental results....

  19. Silver nanocluster catalytic microreactors for water purification

    Science.gov (United States)

    Da Silva, B.; Habibi, M.; Ognier, S.; Schelcher, G.; Mostafavi-Amjad, J.; Khalesifard, H. R. M.; Tatoulian, M.; Bonn, D.

    2016-07-01

    A new method for the elaboration of a novel type of catalytic microsystem with a high specific area catalyst is developed. A silver nanocluster catalytic microreactor was elaborated by doping a soda-lime glass with a silver salt. By applying a high power laser beam to the glass, silver nanoclusters are obtained at one of the surfaces which were characterized by BET measurements and AFM. A microfluidic chip was obtained by sealing the silver coated glass with a NOA 81 microchannel. The catalytic activity of the silver nanoclusters was then tested for the efficiency of water purification by using catalytic ozonation to oxidize an organic pollutant. The silver nanoclusters were found to be very stable in the microreactor and efficiently oxidized the pollutant, in spite of the very short residence times in the microchannel. This opens the way to study catalytic reactions in microchannels without the need of introducing the catalyst as a powder or manufacturing complex packed bed microreactors.

  20. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  1. Non-catalytic recuperative reformer

    Energy Technology Data Exchange (ETDEWEB)

    Khinkis, Mark J.; Kozlov, Aleksandr P.; Kurek, Harry

    2015-12-22

    A non-catalytic recuperative reformer has a flue gas flow path for conducting hot flue gas from a thermal process and a reforming mixture flow path for conducting a reforming mixture. At least a portion of the reforming mixture flow path is embedded in the flue gas flow path to permit heat transfer from the hot flue gas to the reforming mixture. The reforming mixture flow path contains substantially no material commonly used as a catalyst for reforming hydrocarbon fuel (e.g., nickel oxide, platinum group elements or rhenium), but instead the reforming mixture is reformed into a higher calorific fuel via reactions due to the heat transfer and residence time. In a preferred embodiment, extended surfaces of metal material such as stainless steel or metal alloy that are high in nickel content are included within at least a portion of the reforming mixture flow path.

  2. Catalytic Graphitization of Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    Mu Zhao; Huaihe Song

    2011-01-01

    The catalytic graphitization of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate (FN) was studied in detail. The morphologies and structural features of the products including onion-like carbon nanoparticles and bamboo-shaped carbon nanotubes were investigated by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction and Raman spectroscopy measurements. It was found that with the changes of loading content of FN and residence time at 1000℃, the products exhibited various morphologies. The TEM images showed that bamboo-shaped carbon nanotube consisted of tens of bamboo sticks and onion-like carbon nanoparticle was made up of quasi-spherically concentrically closed carbon nanocages.

  3. A New Hard Switching Bidirectional Converter With High Power Density

    OpenAIRE

    Bahador Fani; Majid Delshad; Daryoosh Nazarpour

    2010-01-01

    In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward) and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and compu...

  4. Relative Catalytic Efficiency of ldhL- and ldhD-Encoded Products Is Crucial for Optical Purity of Lactic Acid Produced by Lactobacillus Strains

    OpenAIRE

    Zheng, Zhaojuan; Sheng, Binbin; Ma, Cuiqing; Zhang, Haiwei; Gao, Chao; Su, Fei; Xu, Ping

    2012-01-01

    NAD-dependent l- and d-lactate dehydrogenases coexist in Lactobacillus genomes and may convert pyruvic acid into l-lactic acid and d-lactic acid, respectively. Our findings suggest that the relative catalytic efficiencies of ldhL- and ldhD-encoded products are crucial for the optical purity of lactic acid produced by Lactobacillus strains.

  5. Efficiency of Thermionic and Thermoelectric Converters

    Science.gov (United States)

    Gerstenmaier, York Christian; Wachutka, Gerhard

    2007-02-01

    Thermoelectric and thermionic converters — also in micro- and nano-meter design — are considered for power generation and cooling applications. The potential of thermionic vacuum gap converters is investigated precisely by a new advanced theory with inclusion of backward currents from the 2nd electrode, losses due to thermal radiation and ohmic resistance in the electrodes, tunneling through the gap, image forces, and space charge effects. The efficiency of nano-meter gap thermionic converters is by far higher than for thermoelectric devices (including nano-structured superlattices) for operating temperatures above 800°K, however, there is no chance of realization with today's technology. For a vacuum gap width of about 1 μm the performance is higher than for hypothetical bulk- thermoelectric generators (TEGs) with ZT = 1 for T > 1000°K and also higher than for hypothetical nano-structured superlattices (ZT = 2.4) for T > 1200°K. A thermionic converter with gap width of 5μm has lower performance than a TEG with ZT = 1, however, also operates at T > 1200°K. Reasonable performance of thermionic converters at T ⩽ 500°K necessitates materials with workfunctions ⩽ 0.5 eV.

  6. Ac-dc converter firing error detection

    International Nuclear Information System (INIS)

    Each of the twelve Booster Main Magnet Power Supply modules consist of two three-phase, full-wave rectifier bridges in series to provide a 560 VDC maximum output. The harmonic contents of the twelve-pulse ac-dc converter output are multiples of the 60 Hz ac power input, with a predominant 720 Hz signal greater than 14 dB in magnitude above the closest harmonic components at maximum output. The 720 Hz harmonic is typically greater than 20 dB below the 500 VDC output signal under normal operation. Extracting specific harmonics from the rectifier output signal of a 6, 12, or 24 pulse ac-dc converter allows the detection of SCR firing angle errors or complete misfires. A bandpass filter provides the input signal to a frequency-to-voltage converter. Comparing the output of the frequency-to-voltage converter to a reference voltage level provides an indication of the magnitude of the harmonics in the ac-dc converter output signal

  7. Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-12-01

    This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure

  8. TRANC – a novel fast-response converter to measure total reactive atmospheric nitrogen

    Directory of Open Access Journals (Sweden)

    V. Wolff

    2012-05-01

    Full Text Available The input and loss of plant available nitrogen (reactive nitrogen: Nr from/to the atmosphere can be an important factor for the productivity of ecosystems and thus for its carbon and greenhouse gas exchange. We present a novel converter for reactive nitrogen (TRANC: Total Reactive Atmospheric Nitrogen Converter, which offers the opportunity to quantify the sum of all airborne reactive nitrogen compounds (∑Nr in high time resolution. The basic concept of the TRANC is the full conversion of all Nr to nitrogen monoxide (NO within two reaction steps. Initially, reduced Nr compounds are being oxidised, and oxidised Nr compounds are thermally converted to lower oxidation states. Particulate Nr is being sublimated and oxidised or reduced afterwards. In a second step, remaining higher nitrogen oxides or those generated in the first step are catalytically converted to NO with carbon monoxide used as reduction gas. The converter is combined with a fast response chemiluminescence detector (CLD for NO analysis and its performance was tested for the most relevant gaseous and particulate Nr species under both laboratory and field conditions. Recovery rates during laboratory tests for NH3 and NO2 were found to be 95 and 99%, respectively, and 97% when the two gases were combined. In-field longterm stability over an 11-month period was approved by a value of 91% for NO2. Effective conversion was also found for ammonium and nitrate containing particles. The recovery rate of total ambient Nr was tested against the sum of individual measurements of NH3, HNO3, HONO, NH4+, NO3−, and NOx using a combination of different well-established devices. The results show that the TRANC-CLD system precisely captures fluctuations in ∑Nr concentrations and also matches the sum of all individual Nr compounds measured by the different single techniques. The TRANC features a specific design with very short distance between the sample air inlet and the place where the thermal

  9. An integrated system of gasoline reformer and three way converter for on-board hydrogen production

    International Nuclear Information System (INIS)

    On-board exhaust gas assisted gasoline reforming has been investigated using a compact prototype system consisting of a fuel reformer integrated with a three way catalytic converter (TWC) connected to a V6 engine running at homogeneous charge compression ignition (HCCI) mode, the integrated fuel reformer and TWC were designed and constructed to supply reformed exhaust gas recirculation (REGR) stream to the gasoline-fuelled HCCI V6 engine as supplement fuel to improve engine performance and reduce NOx emissions. To find the optimum operating conditions of the engine-reformer system (in terms of hydrogen production and thermal efficiency), the effect of oxygen to carbon ratio (O2/C) in the reactor input mixture, and the different engine operating conditions were investigated. The reactor outlet temperature appears to be strongly correlated to the production of hydrogen, concentrations up to 12.8% of hydrogen in the reformer products were achieved from commercial unleaded gasoline. Uncompleted reforming of gasoline was assumed from significant quantities of hydrocarbons in the product measured by Non-Dispersive Infrared (NDIR). This novel design of an integrated fuel reformer and three-way catalytic converter (TWC) that can be fitted in the EGR loop was applied to extend the lower boundary of the (HCCI) operating window.(author)

  10. Synchronous Control of Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede; Bose, Bimal K.

    2002-01-01

    A novel method of direct synchronous pulsewidth modulation (PWM) is applied for control of modular multilevel converters consisting from three standard triphase inverter modules along with an 0.33 p.u. output transformer. The proposed method provides synchronisation of the voltage waveforms...... for determination of the pulse patterns, have been analysed and compared using simulations of the systems with low switching frequencies, which normally are used in high power systems....... for each module and the composed voltage at the output of the converter. Multilevel output voltage of the converter has quarter-wave symmetry during the whole range including the zone of overmodulation. Both continuous and discontinuous versions of synchronous PWM, based on vector approach...

  11. Metamaterial polarization converter analysis: limits of performance

    DEFF Research Database (Denmark)

    Markovich, Dmitry L.; Andryieuski, Andrei; Zalkovskij, Maksim;

    2013-01-01

    In this paper, we analyze the theoretical limits of a metamaterial-based converter with orthogonal linear eigenpolarizations that allow linear-to-elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed...... level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50 %, while the realistic reflection configuration can give the conversion efficiency up to 90 %. We show that a double layer transmission converter...... and a single layer with a ground plane can have 100 % polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design...

  12. SIG Galileo final converter technical summary report

    International Nuclear Information System (INIS)

    The report is primarily concerned with the work performed for DOE on converter development and fabrication for the NASA Galileo Jupiter mission as a DOE prime contractor with interface primarily with Teledyne Energy Systems. The activities reported on were directed toward design, analysis and testing of modules and converters SN-1 thru SN-7 and attendant Quality Control and Reliability effort. Although assembly and testing of SN-1 was not accomplished due to the stop work order, the design was virtually completed and a significant amount of subcontracting and manufacturing of both module and converter components was underway. These subcontracting and manufacturing activities were selectively closed down depending upon degree of completion and material or hardware potential usage in the Technology Program

  13. Power system applications for PASC converter systems

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Johnson, R.M. [Montana State Univ., Bozeman, MT (United States)

    1994-04-01

    This paper shows, using computer EMTP simulations, some preliminary results of applying pulse amplitude synthesis and control (PASC) technology to single-source level voltage converter system. The method can be applied to any single terminal pair source with appropriate modifications in power extraction interface and computer control program to match source and load impedance characteristics. The PASC realization as discussed here employs banks of transformers, one bank per phase, in which the primaries are connected in parallel through a switch matrix to the dc source. Two opposite polarity primaries per transformer are pulsed alternatively in time to produce an oscillatory sinusoidal output waveform. PASC conversion system capabilities to produce both leading and lagging power factor power output in single-phase and three-phase {Delta} or Y configurations are illustrated. EMTP simulations are used to demonstrate the converter capabilities. Also included are discussions regarding harmonics and potential control strategies to adapt the converter to an application or to minimize harmonics.

  14. Self-oscillating resonant power converter

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to resonant power converters and inverters comprising a self-oscillating feedback loop coupled from a switch output to a control input of a switching network comprising one or more semiconductor switches. The self-oscillating feedback loop sets a switching frequency...... of the power converter and comprises a first intrinsic switch capacitance coupled between a switch output and a control input of the switching network and a first inductor. The first inductor is coupled in-between a first bias voltage source and the control input of the switching network and has...... a substantially fixed inductance. The first bias voltage source is configured to generate an adjustable bias voltage applied to the first inductor. The output voltage of the power converter is controlled in a flexible and rapid manner by controlling the adjustable bias voltage....

  15. CMOS Integrated Capacitive DC-DC Converters

    CERN Document Server

    Van Breussegem, Tom

    2013-01-01

    This book provides a detailed analysis of all aspects of capacitive DC-DC converter design: topology selection, control loop design and noise mitigation. Readers will benefit from the authors’ systematic overview that starts from the ground up, in-depth circuit analysis and a thorough review of recently proposed techniques and design methodologies.  Not only design techniques are discussed, but also implementation in CMOS is shown, by pinpointing the technological opportunities of CMOS and demonstrating the implementation based on four state-of-the-art prototypes.  Provides a detailed analysis of all aspects of capacitive DC-DC converter design;  Analyzes the potential of this type of DC-DC converter and introduces a number of techniques to unleash their full potential; Combines system theory with practical implementation techniques; Includes unique analysis of CMOS technology for this application; Provides in-depth analysis of four fabricated prototypes.

  16. Single phase AC-DC power factor corrected converter with high frequency isolation using buck converter

    Directory of Open Access Journals (Sweden)

    R. Ramesh,

    2014-03-01

    Full Text Available Single phase ac-dc converters having high frequency isolation are implemented in buck, boost, buck-boost configuration with improving the power quality in terms of reducing the harmonics of input current. The paperpropose the circuit configuration, control mechanism, and simulation result for the single phase ac-dc converter.

  17. Efficient polarization converter for projection displays.

    Science.gov (United States)

    Yip, W C; Huang, H C; Kwok, H S

    1997-09-01

    In the waveguiding limit, a twisted nematic liquid crystal cell behaves as an achromatic polarization rotator. We propose and demonstrate the application of such a polarization rotator to convert unpolarized light into linearly polarized light with almost 100% efficiency. This polarization converter has a 2:1 aspect ratio, which is close to the 16:9 ratio for modern televisions. It can be used therefore in a projection display with polarization-dependent light valves such as a liquid crystal light valve. Both transmittive and reflective light valves can be used. The temperature dependence of the achromatic polarization rotator is also studied. PMID:18259503

  18. A linear temperature-to-frequency converter

    DEFF Research Database (Denmark)

    Løvborg, Leif

    1965-01-01

    , and that the maximum value of the temperature-frequency coefficient beta in this point is-1/3 alpha, where a is the temperature coefficient of the thermistor at the corresponding temperature. Curves showing the range in which the converter is expected to be linear to within plusmn0.1 degC are given. A laboratory......-built converter having beta = 1.0% degC-1 at 25degC is found to be linear to within plusmn0. 1 degC from 10 to 40degC....

  19. Electrodes For Alkali-Metal Thermoelectric Converters

    Science.gov (United States)

    Williams, Roger M.; Wheeler, Bob L.; Jeffries-Nakamura, Barbara; Lamb, James L.; Bankston, C. Perry; Cole, Terry

    1989-01-01

    Combination of thin, porous electrode and overlying collector grid reduces internal resistance of alkali-metal thermoelectric converter cell. Low resistance of new electrode and grid boosts power density nearly to 1 W/cm2 of electrode area at typical operating temperatures of 1,000 to 1,300 K. Conductive grid encircles electrode film on alumina tube. Bus wire runs along tube to collect electrical current from grid. Such converters used to transform solar, nuclear, and waste heat into electric power.

  20. Solar energy converter using surface plasma waves

    Science.gov (United States)

    Anderson, L. M. (Inventor)

    1984-01-01

    Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons.

  1. Efficient modelling of a modular multilevel converter

    DEFF Research Database (Denmark)

    El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

    2013-01-01

    Looking at the near future, we see that offshore wind penetration into the electrical grid will continue increasing rapidly. Until very recently, the trend has been to place the offshore wind farms close to shore within the reach for transmission using HVAC cables but for larger distances HVDC...... calculated for the converter. Time-domain simulations on a MMC HVDC test system are performed in the PSCAD/EMTDC software environment based on the new model. The results demonstrate that the modeled MMC-HVDC system with or without converter transformer is able to operate under specific fault conditions....

  2. Is China Ready for Full Yuan Convertibility?

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Although China has made headway in reforming the exchange rate regime of its currency,the yuan,and expanding the use of it in cross-border trade during the past year,the yuan is far from fully convertible.Huang Yiping,a professor at the National School of Development of Peking University,said in an article for Beijing Review that China has the conditions for capital account liberalization and should strive for basic convertibility within five years. Edited excerpts follow

  3. All linear optical devices are mode converters

    OpenAIRE

    Miller, David A. B.

    2012-01-01

    We show that every linear optical component can be completely described as a device that converts one set of orthogonal input modes, one by one, to a matching set of orthogonal output modes. This result holds for any linear optical structure with any specific variation in space and/or time of its structure. There are therefore preferred orthogonal "mode converter" basis sets of input and output functions for describing any linear optical device, in terms of which the device can be described b...

  4. Combination solar photovoltaic heat engine energy converter

    Science.gov (United States)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  5. Faults and Diagnosis Systems in Power Converters

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Choi, Uimin

    2014-01-01

    A power converter is needed in almost all kinds of renewable energy systems and drive systems. It is used both for controlling the renewable source and for interfacing with the load, which can be grid-connected or working in standalone mode. Further, it drives the motors efficiently. Increasing...... efforts have been put into making these systems better in terms of reliability in order to achieve high power source availability, reduce the cost of energy and also increase the reliability of overall systems. Among the components used in power converters, a power device and a capacitor fault occurs most...

  6. Development of Catalytic Cooking Plates

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, Anna-Karin; Silversand, Fredrik [CATATOR AB, Lund (Sweden); Tena, Emmanuel; Berger, Marc [Gaz de France (France)

    2004-04-01

    Gas catalytic combustion for gas stoves or cooking plates (closed catalytic burner system with ceramic plates) is a very promising technique in terms of ease of cleaning, power modulation and emissions. Previous investigations show that wire mesh catalysts, prepared and supplied by Catator AB (CAT), seem to be very well suited for such applications. Beside significantly reducing the NOx-emissions, these catalysts offer important advantages such as good design flexibility, low pressure drop and high heat transfer capacity, where the latter leads to a quick thermal response. Prior to this project, Gaz de France (GdF) made a series of measurements with CAT's wire mesh catalysts in their gas cooking plates and compared the measured performance with similar results obtained with theirs cordierite monolith catalysts. Compared to the monolith catalyst, the wire mesh catalyst was found to enable very promising results with respect to both emission levels (<10 mg NO{sub x} /kWh, <5 mg CO/kWh) and life-time (>8000 h vs. 700 h at 200 kW/m{sup 2}). It was however established that the radiation and hence, the thermal efficiency of the cooking plate, was significantly less than is usually measured in combination with the monolith (15 % vs. 32 %). It was believed that the latter could be improved by developing new burner designs based on CAT's wire mesh concept. As a consequence, a collaboration project between GdF, CAT and the Swedish Gas Technology AB was created. This study reports on the design, the construction and the evaluation of new catalytic burners, based on CAT's wire mesh catalysts, used for the combustion of natural gas in gas cooking stoves. The evaluation of the burners was performed with respect to key factors such as thermal efficiency, emission quality and pressure drop, etc, by the use of theoretical simulations and experimental tests. Impacts of parameters such as the the wire mesh number, the wire mesh structure (planar or folded), the

  7. Effects of low-temperature catalytic pretreatments on coal structure and reactivity in liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Song, C.; Saini, A.; Huang, L.; Wenzel, K.; Hatcher, P.G.; Schobert, H.H.

    1992-01-01

    Low-temperature catalytic pretreatment is a promising approach to the development of an improved liquefaction process. This work is a fundamental study on effects of pretreatments on coal structure and reactivity in liquefaction. The main objectives of this project are to study the coal structural changes induced by low-temperature catalytic and thermal pretreatments by using spectroscopic techniques; and to clarify the pretreatment-induced changes in reactivity or convertibility of coals in the subsequent liquefaction. This report describes the progress of our work during the first quarterly period. Substantial progress has been made in the spectroscopic characterization of fresh and THF-extracted samples of two subbituminous coals and fresh samples of three bituminous coals using cross-polarization magic angle spinning (CPMAS) solid state {sup 13}C NMR and pyrolysis-GC-MS techniques. CPMAS {sup 13}C NMR and pyrolysis-GC-MS provided important information on carbon distribution/functionality and molecular components/structural units, respectively, for these coal samples. Pyrolysis-GC-MS revealed that there are remarkable structural differences in structural units between the subbituminous coals and the bituminous coals. Furthermore, significant progress has been made in the pretreatments and spectroscopic characterization of catalytically and thermally pretreated as well as physically treated Wyodak subbituminous coal, and temperature-staged and temperature-programmed thermal and catalytic liquefaction of a Montana subbituminous coal.

  8. The effect of noble metals on catalytic methanation reaction over supported Mn/Ni oxide based catalysts

    OpenAIRE

    Wan Azelee Wan Abu Bakar; Rusmidah Ali; Nurul Shafeeqa Mohammad

    2015-01-01

    Carbon dioxide (CO2) in sour natural gas can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4) gas. Using waste to wealth concept, production of CH4 would increase as well as creating environmental friendly approach for the purification of natural gas. In this research, a series of alumina supported manganese–nickel oxide based catalysts doped with noble metals such as ruthenium and palladium were prepared by wetness impregnation method. T...

  9. Removal and Conversion of Tar in Syngas from Woody Biomass Gasification for Power Utilization Using Catalytic Hydrocracking

    OpenAIRE

    Jiu Huang; Klaus Gerhard Schmidt; Zhengfu Bian

    2011-01-01

    Biomass gasification has yet to obtain industrial acceptance. The high residual tar concentrations in syngas prevent any ambitious utilization. In this paper a novel gas purification technology based on catalytic hydrocracking is introduced, whereby most of the tarry components can be converted and removed. Pilot scale experiments were carried out with an updraft gasifier. The hydrocracking catalyst was palladium (Pd). The results show the dominant role of temperature and flow rate. At a cons...

  10. A thermogravimetric analysis (TGA) method to determine the catalytic conversion of cellulose from carbon-supported hydrogenolysis process

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Glauco F. [Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), C.P. 6192, 13083-970 Campinas, SP (Brazil); Institute of Chemistry of São Carlos (IQSC), University of São Paulo (USP), C.P. 780, CEP 13560-970 São Carlos, SP (Brazil); Ramos, Luiz A. [Institute of Chemistry of São Carlos (IQSC), University of São Paulo (USP), C.P. 780, CEP 13560-970 São Carlos, SP (Brazil); Barrett, Dean H. [Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), C.P. 6192, 13083-970 Campinas, SP (Brazil); Curvelo, Antonio Aprígio S. [Institute of Chemistry of São Carlos (IQSC), University of São Paulo (USP), C.P. 780, CEP 13560-970 São Carlos, SP (Brazil); Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), C.P. 6179, 13083-970 Campinas, SP (Brazil); Rodella, Cristiane B., E-mail: cristiane.rodella@lnls.br [Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), C.P. 6192, 13083-970 Campinas, SP (Brazil)

    2015-09-20

    Graphical abstract: - Highlights: • A new method to determine the catalytic conversion of cellulose using TGA has been developed. • TGA is able to differentiate between carbon from cellulose and carbon from the catalyst. • Building an analytical curve from TGA results enables the accurate determination of cellulose conversion. - Abstract: The ability to determine the quantity of solid reactant that has been transformed after a catalytic reaction is fundamental in accurately defining the conversion of the catalyst. This quantity is also central when investigating the recyclability of a solid catalyst as well as process control in an industrial catalytic application. However, when using carbon-supported catalysts for the conversion of cellulose this value is difficult to obtain using only a gravimetric method. The difficulty lies in weighing errors caused by loss of the solid mixture (catalyst and non-converted cellulose) after the reaction and/or moisture adsorption by the substrate. These errors are then propagated into the conversion calculation giving erroneous results. Thus, a quantitative method using thermogravimetric analysis (TGA) has been developed to determine the quantity of cellulose after a catalytic reaction by using a tungsten carbide catalyst supported on activated carbon. Stepped separation of TGA curves was used for quantitative analysis where three thermal events were identified: moisture loss, cellulose decomposition and CO/CO{sub 2} formation. An analytical curve was derived and applied to quantify the residual cellulose after catalytic reactions which were performed at various temperatures and reaction times. The catalytic conversion was calculated and compared to the standard gravimetric method. Results showed that catalytic cellulose conversion can be determined using TGA and exhibits lower uncertainty (±2%) when compared to gravimetric determination (±5%). Therefore, it is a simple and relatively inexpensive method to determine

  11. Catalytic processes towards the production of biofuels in a palm oil and oil palm biomass-based biorefinery.

    Science.gov (United States)

    Chew, Thiam Leng; Bhatia, Subhash

    2008-11-01

    In Malaysia, there has been interest in the utilization of palm oil and oil palm biomass for the production of environmental friendly biofuels. A biorefinery based on palm oil and oil palm biomass for the production of biofuels has been proposed. The catalytic technology plays major role in the different processing stages in a biorefinery for the production of liquid as well as gaseous biofuels. There are number of challenges to find suitable catalytic technology to be used in a typical biorefinery. These challenges include (1) economic barriers, (2) catalysts that facilitate highly selective conversion of substrate to desired products and (3) the issues related to design, operation and control of catalytic reactor. Therefore, the catalytic technology is one of the critical factors that control the successful operation of biorefinery. There are number of catalytic processes in a biorefinery which convert the renewable feedstocks into the desired biofuels. These include biodiesel production from palm oil, catalytic cracking of palm oil for the production of biofuels, the production of hydrogen as well as syngas from biomass gasification, Fischer-Tropsch synthesis (FTS) for the conversion of syngas into liquid fuels and upgrading of liquid/gas fuels obtained from liquefaction/pyrolysis of biomass. The selection of catalysts for these processes is essential in determining the product distribution (olefins, paraffins and oxygenated products). The integration of catalytic technology with compatible separation processes is a key challenge for biorefinery operation from the economic point of view. This paper focuses on different types of catalysts and their role in the catalytic processes for the production of biofuels in a typical palm oil and oil palm biomass-based biorefinery. PMID:18434141

  12. Catalytic Conversion of 2-Naphthol to 2-Hydroxy-1,4-naphthoquinone Under Mild Conditions

    Institute of Scientific and Technical Information of China (English)

    YAN,Yan(阎雁); GUO,Hong-Wei(郭红卫); JIAN,Wen-Ping(菅文平); YANG,Ke-Er(杨克儿); TONG,Shan-Ling(佟珊玲); FANG,Chi-Guang(方赤光); Ll,Qing(李青); CHANG,Xin(常新)

    2004-01-01

    2-Hydroxy-l,4-naphthaquinone (HNQ) was selectively synthesized from catalytic oxidation of 2-naphthol by molecular oxygen over tetra(4-methoxyl-phenyl)porphyrinate iron(III) chloride (TMOPPFeC1) catalyst in an alkali methanol solution under mild conditions.The influences of solvents,temperature,time,as well as amounts of catalysts and alkali were studied.The quantitative data show that 32.9% of 2-naphthol (0.093 mol/dm3) was catalytically converted to HNQ with the selectivity of 100% at 323 K for 9 h over TMOPPFeC1 catalyst (2.54×10-4mol/dm3) in alkali media (30 mL of methanol containing 2.5 mol/dm3 of NaOH) by flowing molecular oxygen (flowing rate of 45 mL/min).

  13. Catalytic oxidation for treatment of ECLSS and PMMS waste streams. [Process Material Management Systems

    Science.gov (United States)

    Akse, James R.; Thompson, John; Scott, Bryan; Jolly, Clifford; Carter, Donald L.

    1992-01-01

    Catalytic oxidation was added to the baseline multifiltration technology for use on the Space Station Freedom in order to convert low-molecular weight organic waste components such as alcohols, aldehydes, ketones, amides, and thiocarbamides to CO2 at low temperature (121 C), thereby reducing the total organic carbon (TOC) to below 500 ppb. The rate of reaction for the catalytic oxidation of aqueous organics to CO2 and water depends primarily upon the catalyst, temperature, and concentration of reactants. This paper describes a kinetic study conducted to determine the impact of each of these parameters upon the reaction rate. The results indicate that a classic kinetic model, the Langmuir-Hinshelwood rate equation for heterogeneous catalysis, can accurately represent the functional dependencies of this rate.

  14. Low-temperature catalytic gasification of food processing wastes. 1995 topical report

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, D.C.; Hart, T.R.

    1996-08-01

    The catalytic gasification system described in this report has undergone continuing development and refining work at Pacific Northwest National Laboratory (PNNL) for over 16 years. The original experiments, performed for the Gas Research Institute, were aimed at developing kinetics information for steam gasification of biomass in the presence of catalysts. From the fundamental research evolved the concept of a pressurized, catalytic gasification system for converting wet biomass feedstocks to fuel gas. Extensive batch reactor testing and limited continuous stirred-tank reactor tests provided useful design information for evaluating the preliminary economics of the process. This report is a follow-on to previous interim reports which reviewed the results of the studies conducted with batch and continuous-feed reactor systems from 1989 to 1994, including much work with food processing wastes. The discussion here provides details of experiments on food processing waste feedstock materials, exclusively, that were conducted in batch and continuous- flow reactors.

  15. Selective catalytic reduction of nitrogen oxides from industrial gases by hydrogen or methane

    International Nuclear Information System (INIS)

    This work deals with the selective catalytic reduction of nitrogen oxides (NOx), contained in the effluents of industrial plants, by hydrogen or methane. The aim is to replace ammonia, used as reducing agent, in the conventional process. The use of others reducing agents such as hydrogen or methane is interesting for different reasons: practical, economical and ecological. The catalyst has to convert selectively NO into N2, in presence of an excess of oxygen, steam and sulfur dioxide. The developed catalyst is constituted by a support such as perovskites, particularly LaCoO3, on which are dispersed noble metals (palladium, platinum). The interaction between the noble metal and the support, generated during the activation of the catalyst, allows to minimize the water and sulfur dioxide inhibitor phenomena on the catalytic performances, particularly in the reduction of NO by hydrogen. (O.M.)

  16. Catalytic conversion of light alkanes, Phase 1. Topical report, January 1990--January 1993

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-31

    The authors have found a family of new catalytic materials which, if successfully developed, will be effective in the conversion of light alkanes to alcohols or other oxygenates. Catalysts of this type have the potential to convert natural gas to clean-burning high octane liquid fuels directly without requiring the energy-intensive steam reforming step. In addition they also have the potential to upgrade light hydrocarbons found in natural gas to a variety of high value fuel and chemical products. In order for commercially useful processes to be developed, increases in catalytic life, reaction rate and selectivity are required. Recent progress in the experimental program geared to the further improvement of these catalysts is outlined.

  17. Catalytic Chemistry on Oxide Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Asthagiri, Aravind; Dixon, David A.; Dohnalek, Zdenek; Kay, Bruce D.; Rodriquez, Jose A.; Rousseau, Roger J.; Stacchiola, Dario; Weaver, Jason F.

    2016-05-29

    Metal oxides represent one of the most important and widely employed materials in catalysis. Extreme variability of their chemistry provides a unique opportunity to tune their properties and to utilize them for the design of highly active and selective catalysts. For bulk oxides, this can be achieved by varying their stoichiometry, phase, exposed surface facets, defect, dopant densities and numerous other ways. Further, distinct properties from those of bulk oxides can be attained by restricting the oxide dimensionality and preparing them in the form of ultrathin films and nanoclusters as discussed throughout this book. In this chapter we focus on demonstrating such unique catalytic properties brought by the oxide nanoscaling. In the highlighted studies planar models are carefully designed to achieve minimal dispersion of structural motifs and to attain detailed mechanistic understanding of targeted chemical transformations. Detailed level of morphological and structural characterization necessary to achieve this goal is accomplished by employing both high-resolution imaging via scanning probe methods and ensemble-averaged surface sensitive spectroscopic methods. Three prototypical examples illustrating different properties of nanoscaled oxides in different classes of reactions are selected.

  18. Halogen Chemistry on Catalytic Surfaces.

    Science.gov (United States)

    Moser, Maximilian; Pérez-Ramírez, Javier

    2016-01-01

    Halogens are key building blocks for the manufacture of high-value products such as chemicals, plastics, and pharmaceuticals. The catalytic oxidation of HCl and HBr is an attractive route to recover chlorine and bromine in order to ensure the sustainability of the production processes. Very few materials withstand the high corrosiveness and the strong exothermicity of the reactions and among them RuO2 and CeO2-based catalysts have been successfully applied in HCl oxidation. The search for efficient systems for HBr oxidation was initiated by extrapolating the results of HCl oxidation based on the chemical similarity of these reactions. Interestingly, despite its inactivity in HCl oxidation, TiO2 was found to be an outstanding HBr oxidation catalyst, which highlighted that the latter reaction is more complex than previously assumed. Herein, we discuss the results of recent comparative studies of HCl and HBr oxidation on both rutile-type (RuO2, IrO2, and TiO2) and ceria-based catalysts using a combination of advanced experimental and theoretical methods to provide deeper molecular-level understanding of the reactions. This knowledge aids the design of the next-generation catalysts for halogen recycling. PMID:27131113

  19. Bidirectional converter interface for a battery energy storage test bench

    DEFF Research Database (Denmark)

    Trintis, Ionut; Thomas, Stephan; Blank, Tobias;

    2011-01-01

    This paper presents the bidirectional converter interface for a 6 kV battery energy storage test bench. The power electronic interface consists a two stage converter topology having a low voltage dc-ac grid connected converter and a new dual active bridge dc-dc converter with high transformation...

  20. Integrated multilevel converter and battery management

    OpenAIRE

    K. Wilkie; Stone, D.; Bingham, C.; Foster, M.

    2008-01-01

    A cascaded H-bridge multilevel converter is proposed as a BLDC drive incorporating real-time battery management. Intelligent H-bridges are used to monitor battery cells whilst simultaneously increasing their performance by reducing the variation between cells and controlling their discharge profiles.

  1. Angiotensin converting enzyme inhibitor induced hyperkalaemic paralysis

    OpenAIRE

    Dutta., D; Fischler, M; McClung, A

    2001-01-01

    Secondary hyperkalaemic paralysis is a rare condition often mimicking the Guillain-Barré syndrome. There have been a few case reports of hyperkalaemia caused by renal failure, trauma, and drugs where the presentation has been with muscle weakness. A case of hyperkalaemic paralysis caused by an angiotensin converting enzyme inhibitor is reported.


Keywords: hyperkalaemia; paralysis; ACE inhibitors

  2. China to Gradually Make Capital Account Convertible

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ China is pushing forward its currency Renminbi (RMB)'s capital account convertibility gradually and in a stable manner, said an official with the State Administration of Foreign Exchange (SAFE), ruling out both an adventurous leap and conservative cautiousness, according to a report of Xinhua on April 12.

  3. China to Gradually Make Capital Account Convertible

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

      China is pushing forward its currency Renminbi (RMB)'s capital account convertibility gradually and in a stable manner, said an official with the State Administration of Foreign Exchange (SAFE), ruling out both an adventurous leap and conservative cautiousness, according to a report of Xinhua on April 12.……

  4. Online Scheduling in Distributed Message Converter Systems

    NARCIS (Netherlands)

    Risse, Thomas; Wombacher, Andreas; Surridge, Mike; Taylor, Steve; Aberer, Karl

    2001-01-01

    The optimal distribution of jobs among hosts in distributed environments is an important factor to achieve high performance. The optimal strategy depends on the application. In this paper we present a new online scheduling strategy for distributed EDI converter system. The strategy is based on the B

  5. Impedance interactions in bidirectional cascaded converter

    DEFF Research Database (Denmark)

    Tian, Yanjun; Loh, Poh Chiang; Chen, Zhe;

    2016-01-01

    here for showing that forward and reverse interactions are prominently different in terms of dynamics and stability, even though the cascaded converter control remains unchanged. The concluded findings have been verified by simulation and experimental results, from which, important guidelines have been...

  6. Power electronics converters for wind turbine systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Liserre, Marco; Ma, Ke

    2011-01-01

    The steady growth of installed wind power which reached 200 GW capacity in 2010, together with the up-scaling of the single wind turbine power capability - 7 MW’s has been announced by manufacturers - has pushed the research and development of power converters towards full scale power conversion,...

  7. Power Electronics Converters for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Liserre, Marco; Ma, Ke

    2012-01-01

    The steady growth of installed wind power together with the upscaling of the single wind turbine power capability has pushed the research and development of power converters toward full-scale power conversion, lowered cost pr kW, increased power density, and also the need for higher reliability. ...

  8. Generalized modular multilevel converter and modulation

    DEFF Research Database (Denmark)

    Liu, Hui; Loh, Poh Chiang; Blaabjerg, Frede

    2014-01-01

    Modular multilevel converter (MMC) has gained popularity recently with its modulation, capacitor voltage balancing and circulating current issues widely discussed. Contributing to this effort, a study is presented here to show how the MMC topology can be derived from the viewpoint of two series c...

  9. Performance Evaluation of Wave Energy Converters

    DEFF Research Database (Denmark)

    Pecher, Arthur

    stages, and results thereby in a need for specific test objectives and procedures for each development stage. This PhD thesis has looked into the different development stages and more specifically in the performance assessment of wave energy converters based on tank testing and sea trials. The objective...

  10. Performance Evaluation of Wave Energy Converters

    DEFF Research Database (Denmark)

    Pecher, Arthur

    stages, and results thereby in a need for specific testobjectives and procedures for each development stage. This PhD thesis has looked into the different development stages and more specifically in the performance assessment of wave energy converters based on tank testing and sea trials. The objective...

  11. Efficient, lightweight dc/dc switching converter

    Science.gov (United States)

    Cuk, S.; Middlebrook, R. D.

    1981-01-01

    Converters have input properties of boost power stage and output properties of buck power stage, yet they perform general conversion function with high efficiency. Other features include non-pulsating input/output currents, use of capacitive energy transfer, low output voltage ripple, reduced EMI, and small size.

  12. Convertible bonds and bank risk-taking

    NARCIS (Netherlands)

    N. Martynova; E. Perotti

    2015-01-01

    We study how contingent capital that converts in equity ahead of default affects bankrisk-shifting. Going concern conversion restores equity value in highly levered states,thus reducing heightened risk incentives. In contrast, conversion at default for traditionalbail-inable debt has no effect on en

  13. Mathematical modeling of the flash converting process

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, H.Y.; Perez-Tello, M.; Riihilahti, K.M. [Utah Univ., Salt Lake City, UT (United States)

    1996-12-31

    An axisymmetric mathematical model for the Kennecott-Outokumpu flash converting process for converting solid copper matte to copper is presented. The model is an adaptation of the comprehensive mathematical model formerly developed at the University of Utah for the flash smelting of copper concentrates. The model incorporates the transport of momentum, heat, mass, and reaction kinetics between gas and particles in a particle-laden turbulent gas jet. The standard k-{epsilon} model is used to describe gas-phase turbulence in an Eulerian framework. The particle-phase is treated from a Lagrangian viewpoint which is coupled to the gas-phase via the source terms in the Eulerian gas-phase governing equations. Matte particles were represented as Cu{sub 2}S yFeS, and assumed to undergo homogeneous oxidation to Cu{sub 2}O, Fe{sub 3}O{sub 4}, and SO{sub 2}. A reaction kinetics mechanism involving both external mass transfer of oxygen gas to the particle surface and diffusion of oxygen through the porous oxide layer is proposed to estimate the particle oxidation rate Predictions of the mathematical model were compared with the experimental data collected in a bench-scale flash converting facility. Good agreement between the model predictions and the measurements was obtained. The model was used to study the effect of different gas-injection configurations on the overall fluid dynamics in a commercial size flash converting shaft. (author)

  14. Converting Student Support Services to Online Delivery.

    Science.gov (United States)

    Brigham, David E.

    2001-01-01

    Uses a systems framework to analyze the creation of student support services for distance education at Regents College: electronic advising, electronic peer network, online course database, online bookstore, virtual library, and alumni services website. Addresses the issues involved in converting distance education programs from print-based and…

  15. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  16. Development of the Wave Energy Converter

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Sørensen, Hans Christian;

    2000-01-01

    The development of the wave energy converter Wave Dragon (WD) is presented. The WD is based on the overtopping principle. Initially a description of the WD is given. Then the development over time in terms of the various research and development projects working with the concept is described...

  17. Aquabuoy Wave Energy Converter

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Frigaard, Peter

    The work reported here is part of the contract agreement between the Finavera Renewables Ocean Energy Ltd. and the Department of Civil Engineering Hydraulics and Coastal Engineering Laboratory to instrument a model in scale 1:10 to prototype of the AquaBuOY (AB) wave energy converter and to analyse...

  18. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Catalytic Conversion of Sugars to Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.; Tao, L.; Scarlata, C.; Tan, E. C. D.; Ross, J.; Lukas, J.; Sexton, D.

    2015-03-01

    This report describes one potential conversion process to hydrocarbon products by way of catalytic conversion of lignocellulosic-derived hydrolysate. This model leverages expertise established over time in biomass deconstruction and process integration research at NREL, while adding in new technology areas for sugar purification and catalysis. The overarching process design converts biomass to die die diesel- and naphtha-range fuels using dilute-acid pretreatment, enzymatic saccharification, purifications, and catalytic conversion focused on deoxygenating and oligomerizing biomass hydrolysates.

  19. A New Hard Switching Bidirectional Converter With High Power Density

    Directory of Open Access Journals (Sweden)

    Bahador Fani

    2010-01-01

    Full Text Available In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.

  20. Catalytic models developed through social work

    DEFF Research Database (Denmark)

    Jensen, Mogens

    2015-01-01

    The article develops the concept of catalytic processes in relation to social work with adolescents in an attempt to both reach a more nuanced understanding of social work and at the same time to develop the concept of catalytic processes in psychology. The social work is pedagogical treatment...... of adolescents placed in out-of-home care and is characterised using three situated cases as empirical data. Afterwards the concept of catalytic processes is briefly presented and then applied in an analysis of pedagogical treatment in the three cases. The result is a different conceptualisation of the social...... work with new possibilities of development of the work, but also suggestions for development of the concept of catalytic processes....

  1. MOBILE COMPLEX FOR CATALYTIC THERMAL WASTE TREATMENT

    Directory of Open Access Journals (Sweden)

    Vedi V.E.

    2012-12-01

    Full Text Available The design and purpose of the basic units of the mobile waste processing complex “MPK” are described. Experimental data of catalytic purification of exhaust gases are presented. Experimental data on catalytic clearing of final gases of a designed mobile incinerator plant are shown. It is defined, that concentrating of parasitic bridging in waste gases of the complex are considerably smaller, rather than allowed by normative documents.

  2. MOBILE COMPLEX FOR CATALYTIC THERMAL WASTE TREATMENT

    OpenAIRE

    Vedi V.E.; Rovenskii A.I.

    2012-01-01

    The design and purpose of the basic units of the mobile waste processing complex “MPK” are described. Experimental data of catalytic purification of exhaust gases are presented. Experimental data on catalytic clearing of final gases of a designed mobile incinerator plant are shown. It is defined, that concentrating of parasitic bridging in waste gases of the complex are considerably smaller, rather than allowed by normative documents.

  3. Catalytic Radical Domino Reactions in Organic Synthesis

    Science.gov (United States)

    Sebren, Leanne J.; Devery, James J.; Stephenson, Corey R.J.

    2014-01-01

    Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes. PMID:24587964

  4. Catalytic ammonia oxidation to nitrogen (I) oxide

    OpenAIRE

    MASALITINA NATALIYA YUREVNA; SAVENKOV ANATOLIY SERGEEVICH

    2015-01-01

    The process of synthesis of nitrous oxide by low-temperature catalytical oxidation of NH has been investigated for organic synthesis. The investigation has been carried out by the stage separation approach with NH oxidation occurring in several reaction zones, which characterized by different catalytic conditions. The selectivity for N₂O was 92–92,5 % at the ammonia conversion of 98–99.5 % in the optimal temperature range.

  5. Temperature Modulation of a Catalytic Gas Sensor

    OpenAIRE

    Eike Brauns; Eva Morsbach; Sebastian Kunz; Marcus Baeumer; Walter Lang

    2014-01-01

    The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response time, which allows advanced analysis of the sensor response. By using temperature modulation, additi...

  6. Preparation and Catalytic Oxidation Activity on 2-mercaptoethanol of a Novel Catalytic Cellulose Fibres

    Institute of Scientific and Technical Information of China (English)

    YAO Yu-yuan; LI Ying-jie; CHEN Wen-xing; Lü Wang-yang; Lü Su-fang; XU Min-hong; LIU Fan

    2007-01-01

    Cobalt tetra(N-carbonylacylic) aminophthalocyanine was supported on cellulose fibres by graft reaction to obtain a novel polymer catalyst, catalytic cellulose fibres (CCF),and the optimal supporting conditions were pH = 6, 80℃,t = 120 min. The catalytic oxidation activity of CCF towards oxidation of 2-mereaptoethanol (MEA) in aqueous solution was investigated. The experimental results demonstrated that CCF had good catalytic oxidation activity on MEA at room temperature, causing no secondary pollution and remaining efficient for the repetitive tests with no obvious decrease of catalytic activity.

  7. A low-voltage boost converter using a forward converter with integrated Meissner oscillator

    International Nuclear Information System (INIS)

    This paper describes a novel boost converter to be used with energy harvesters that provide only low output voltages. The device is self-supplied from electric power delivered to its input. With peak power conversion efficiencies above 30% at start-up voltages down to 10 mV this circuit sets best values in comparison with the state-of-the-art. This is achieved by the novel combination of a Meissner oscillator, used as stand-alone in most low-voltage step-up converters today, with a forward converter usually applied in high power systems

  8. Multi-output DC-DC converters based on diode-clamped converters configuration

    DEFF Research Database (Denmark)

    Nami, A.; Zare, F.; Ghosh, A.;

    2010-01-01

    for a diode-clamed inverter in the grid connection systems, where boosting low rectified output-voltage and series DC link capacitors is required. To verify the proposed topology, steady-state and dynamic analyses of a MOB converter are examined. A simple control strategy has been proposed to demonstrate...... the performance of the proposed topology for a double-output boost converter. The topology and its control strategy can easily be extended to offer multiple outputs. Simulation and experimental results are presented to show the validity of the control strategy for the proposed converter....

  9. A low-voltage boost converter using a forward converter with integrated Meissner oscillator

    Science.gov (United States)

    Woias, P.; Islam, M.; Heller, S.; Roth, R.

    2013-12-01

    This paper describes a novel boost converter to be used with energy harvesters that provide only low output voltages. The device is self-supplied from electric power delivered to its input. With peak power conversion efficiencies above 30% at start-up voltages down to 10 mV this circuit sets best values in comparison with the state-of-the-art. This is achieved by the novel combination of a Meissner oscillator, used as stand-alone in most low-voltage step-up converters today, with a forward converter usually applied in high power systems.

  10. ORGANIC CHEMISTRY. Catalytic asymmetric hydroamination of unactivated internal olefins to aliphatic amines.

    Science.gov (United States)

    Yang, Yang; Shi, Shi-Liang; Niu, Dawen; Liu, Peng; Buchwald, Stephen L

    2015-07-01

    Catalytic assembly of enantiopure aliphatic amines from abundant and readily available precursors has long been recognized as a paramount challenge in synthetic chemistry. Here, we describe a mild and general copper-catalyzed hydroamination that effectively converts unactivated internal olefins—an important yet unexploited class of abundant feedstock chemicals—into highly enantioenriched α-branched amines (≥96% enantiomeric excess) featuring two minimally differentiated aliphatic substituents. This method provides a powerful means to access a broad range of advanced, highly functionalized enantioenriched amines of interest in pharmaceutical research and other areas.

  11. Tunable catalytic properties of bi-functional mixed oxides in ethanol conversion to high value compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ramasamy, Karthikeyan K.; Gray, Michel J.; Job, Heather M.; Smith, Colin D.; Wang, Yong

    2016-04-10

    tA highly versatile ethanol conversion process to selectively generate high value compounds is pre-sented here. By changing the reaction temperature, ethanol can be selectively converted to >C2alcohols/oxygenates or phenolic compounds over hydrotalcite derived bi-functional MgO–Al2O3cata-lyst via complex cascade mechanism. Reaction temperature plays a role in whether aldol condensationor the acetone formation is the path taken in changing the product composition. This article containsthe catalytic activity comparison between the mono-functional and physical mixture counterpart to thehydrotalcite derived mixed oxides and the detailed discussion on the reaction mechanisms.

  12. Catalytic Hydrodechlorination of Trichlorobenzenes with Pd(PhenCl2 as Catalyst Precursor

    Directory of Open Access Journals (Sweden)

    Guanlin Zhang

    2015-01-01

    Full Text Available We reported the catalytic hydrodechlorination (HDC of trichlorobenzenes by an organometallic compound Pd(PhenCl2 as a catalyst precursor. The catalyst precursor was prepared by chemical coordination reaction and characterized by FTIR and 1H NMR techniques. The HDC performance of Pd(PhenCl2 as catalyst precursor was evaluated on 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes (TCBs. All TCBs could be converted to dechlorination products with high conversion. Products distribution was closely related with the substrate structures and C-Cl bond energies. A reasonable reaction mechanism was also proposed.

  13. Catalytic conversion of alcohols having at least three carbon atoms to hydrocarbon blendstock

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.

    2015-11-13

    A method for producing a hydrocarbon blendstock, the method comprising contacting at least one saturated acyclic alcohol having at least three and up to ten carbon atoms with a metal-loaded zeolite catalyst at a temperature of at least 100°C and up to 550°C, wherein the metal is a positively-charged metal ion, and the metal-loaded zeolite catalyst is catalytically active for converting the alcohol to the hydrocarbon blendstock, wherein the method directly produces a hydrocarbon blendstock having less than 1 vol % ethylene and at least 35 vol % of hydrocarbon compounds containing at least eight carbon atoms.

  14. Research on Converter Valve Overvoltage Mechanism and Calculation Conditions of ± 800 kV Converter Station

    Institute of Scientific and Technical Information of China (English)

    WANG Dongju; DENG Xu; ZHOU Hao; CHEN Xilei; XU Anwen; SHEN Yang

    2012-01-01

    The thyristor converter valve is the key equipment of commutation in ultra high voltage direct current (UHVDC) transmission systems. Owing to the limited voltage and current overload capacity, any transient overvoltage may cause permanent damage to the thyristor converter valve. In order to specify the converter valves' overvoltage levels of the ±800 kV UHVDC transmission system, the mechanisms of its generation and development are discussed in detail, from which the calculation conditions for the highest stresses of the converter valves are given. Finally, the converter valve's overvoltage of Xiluodu UHV converter station is simulated. The research results show that the overvoltages of the converter valves in the upper 3-pulse group of the high voltage(HV) and low voltage(LV) 12-pulse converter are generated jointly by the DC line voltage and the converter transformer's voltage at its valve side. Calculation conditions for this overvoltage are: DC system in bipolar operation mode, converter station operating as rectifier, maximum DC system operating voltage, minimum DC current, minimum AC system voltage of the converter station. Furthermore, the other converter valves' overvoltage is caused by the phase-to-phase switching surge generated at the converter station's AC side, penetrating into the valve hall. Overall, the maximum overvoltages of Xiluodu converter station in the upper 3-pulse group of the HV and LV 12-pulse converter are 379.1 kV and 384.9 kV, for other converter valves the maximum overvoltage is 375.3 kV.

  15. Imbalance between pulmonary angiotensin-converting enzyme and angiotensin-converting enzyme 2 activity in acute respiratory distress syndrome

    NARCIS (Netherlands)

    Wosten-van Asperen, Roelie M.; Bos, Albert; Bem, Reinout A.; Dierdorp, Barbara S.; Dekker, Tamara; van Goor, Harry; Kamilic, Jelena; van der Loos, Chris M.; van den Berg, Elske; Bruijn, Martijn; van Woensel, Job B.; Lutter, Rene

    2013-01-01

    Objective: Angiotensin-converting enzyme and its effector peptide angiotensin II have been implicated in the pathogenesis of acute respiratory distress syndrome. Recently, angiotensin-converting enzyme 2 was identified as the counter-regulatory enzyme of angiotensin-converting enzyme that converts a

  16. Efficient Wide Range Converters (EWiRaC): A new family of high efficient AC-DC Converters

    DEFF Research Database (Denmark)

    Petersen, Lars; Andersen, Michael Andreas E.

    2006-01-01

    The performance in terms of efficiency of the existing power supplies used for PFC is very dependent on the input voltage range. The boost converter is the most commonly used PFC converter because of its simplicity and high efficiency. But, the boost converter as well as other known converters...... the converter topology according to the input voltage. This new converter type has been named: efficient wide range converter (EWiRaC). The performance of the EWiRaC is experimental verified in a universal input range (90-270VAC) application with an output voltage of 185VDC capable of 500W output power. The EWi...

  17. Catalytic hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, B.B.

    1992-12-01

    This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

  18. Dimethyl carbonate as potential reactant in non-catalytic biodiesel production by supercritical method.

    Science.gov (United States)

    Ilham, Zul; Saka, Shiro

    2009-03-01

    In this study, the non-catalytic supercritical method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal. After 12 min of reaction at 350 degrees C/20 MPa, rapeseed oil treated with supercritical dimethyl carbonate reached 94% (w/w) yield of fatty acid methyl ester. The by-products from this process which are glycerol carbonate and citramalic acid are much higher in value than glycerol produced by the conventional process. In addition, the yield of the fatty acid methyl esters as biodiesel was almost at par with supercritical methanol method. Therefore, supercritical dimethyl carbonate process can be a good candidate as an alternative biodiesel production process. PMID:18990561

  19. On the Structural Context and Identification of Enzyme Catalytic Residues

    OpenAIRE

    Yu-Tung Chien; Shao-Wei Huang

    2013-01-01

    Enzymes play important roles in most of the biological processes. Although only a small fraction of residues are directly involved in catalytic reactions, these catalytic residues are the most crucial parts in enzymes. The study of the fundamental and unique features of catalytic residues benefits the understanding of enzyme functions and catalytic mechanisms. In this work, we analyze the structural context of catalytic residues based on theoretical and experimental structure flexibility. The...

  20. TiConverter: A training image converting tool for multiple-point geostatistics

    Science.gov (United States)

    Fadlelmula F., Mohamed M.; Killough, John; Fraim, Michael

    2016-11-01

    TiConverter is a tool developed to ease the application of multiple-point geostatistics whether by the open source Stanford Geostatistical Modeling Software (SGeMS) or other available commercial software. TiConverter has a user-friendly interface and it allows the conversion of 2D training images into numerical representations in four different file formats without the need for additional code writing. These are the ASCII (.txt), the geostatistical software library (GSLIB) (.txt), the Isatis (.dat), and the VTK formats. It performs the conversion based on the RGB color system. In addition, TiConverter offers several useful tools including image resizing, smoothing, and segmenting tools. The purpose of this study is to introduce the TiConverter, and to demonstrate its application and advantages with several examples from the literature.