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Sample records for plate methanol steam

  1. Fabrication and characteristics of cube-post microreactors for methanol steam reforming

    International Nuclear Information System (INIS)

    Zeng, Dehuai; Pan, Minqiang; Wang, Liming; Tang, Yong

    2012-01-01

    Highlights: ► We developed a cube-post microreactor for methanol steam reforming. ► We investigated the influences of micro-milling parameters on the burr formation during fabricating the cube posts. ► Larger cutting speed, smaller feed rate and cutting depth are in favor of obtaining relatively small burrs. ► Cube post and manifold structure show important effects on reaction performances at relatively low reaction temperature. -- Abstract: The lamination-plate structure patterned with microchannels and triangle manifolds regarded as one of the preferred constructions for micro fuel reformers. Learned from the microchannel plate structure, a similar plate structure with cube-post array and triangle manifolds is proposed in this work. A micro-milling process is applied to fabricate the cube posts on the plate surface, and the influences of cutting parameters on the burr formation are analyzed. Experimental results indicate that larger cutting speed, smaller feed rate and cutting depth are in favor of obtaining relatively small burrs. Two plates with different cube-post dimensions and manifold structures are experimentally investigated the performances of methanol steam reforming over the Cu/Zn/Al/Zr catalyst. It indicates that the reactor with small-scale cube posts and acute triangle manifold presents better reforming performances at 260 °C than that of the one with large-scale cube posts and right triangle manifolds. However, their performances are closed to each other at relatively high reaction temperature since the catalyst activity is situated in dominated position at the time.

  2. Thermoelectric generation coupling methanol steam reforming characteristic in microreactor

    International Nuclear Information System (INIS)

    Wang, Feng; Cao, Yiding; Wang, Guoqiang

    2015-01-01

    Thermoelectric (TE) generator converts heat to electric energy by thermoelectric material. However, heat removal on the cold side of the generator represents a serious challenge. To address this problem and for improved energy conversion, a thermoelectric generation process coupled with methanol steam reforming (SR) for hydrogen production is designed and analyzed in this paper. Experimental study on the cold spot character in a micro-reactor with monolayer catalyst bed is first carried out to understand the endothermic nature of the reforming as the thermoelectric cold side. A novel methanol steam reforming micro-reactor heated by waste heat or methanol catalytic combustion for hydrogen production coupled with a thermoelectric generation module is then simulated. Results show that the cold spot effect exists in the catalyst bed under all conditions, and the associated temperature difference first increases and then decreases with the inlet temperature. In the micro-reactor, the temperature difference between the reforming and heating channel outlets decreases rapidly with an increase in thermoelectric material's conductivity coefficient. However, methanol conversion at the reforming outlet is mainly affected by the reactor inlet temperature; while at the combustion outlet, it is mainly affected by the reactor inlet velocity. Due to the strong endothermic effect of the methanol steam reforming, heat supply of both kinds cannot balance the heat needed at reactor local areas, resulting in the cold spot at the reactor inlet. When the temperature difference between the thermoelectric module's hot and cold sides is 22 K, the generator can achieve an output voltage of 55 mV. The corresponding molar fraction of hydrogen can reach about 62.6%, which corresponds to methanol conversion rate of 72.6%. - Highlights: • Cold spot character of methanol steam reforming was studied through experiment. • Thermoelectric generation Coupling MSR process has been

  3. Modeling and simulation of an isothermal reactor for methanol steam reforming

    Directory of Open Access Journals (Sweden)

    Raphael Menechini Neto

    2014-04-01

    Full Text Available Due to growing electricity demand, cheap renewable energy sources are needed. Fuel cells are an interesting alternative for generating electricity since they use hydrogen as their main fuel and release only water and heat to the environment. Although fuel cells show great flexibility in size and operating temperature (some models even operate at low temperatures, the technology has the drawback for hydrogen transportation and storage. However, hydrogen may be produced from methanol steam reforming obtained from renewable sources such as biomass. The use of methanol as raw material in hydrogen production process by steam reforming is highly interesting owing to the fact that alcohol has the best hydrogen carbon-1 ratio (4:1 and may be processed at low temperatures and atmospheric pressures. They are features which are desirable for its use in autonomous fuel cells. Current research develops a mathematical model of an isothermal methanol steam reforming reactor and validates it against experimental data from the literature. The mathematical model was solved numerically by MATLAB® and the comparison of its predictions for different experimental conditions indicated that the developed model and the methodology for its numerical solution were adequate. Further, a preliminary analysis was undertaken on methanol steam reforming reactor project for autonomous fuel cell.

  4. Effect of pervaporation plate thickness on the rate of methanol evaporation in a passive vapor-feed direct methanol fuel cell

    Science.gov (United States)

    Fauzi, N. F. I.; Hasran, U. A.; Kamarudin, S. K.

    2015-09-01

    In a passive vapor-feed direct methanol fuel cell (DMFC), methanol vapor is typically obtained using a pervaporation plate in a process by which liquid methanol contained in the fuel reservoir undergoes a phase change to vapor in the anodic vapor chamber. This work investigates the effect of pervaporation plate thickness on the rate of methanol evaporation using a three-dimensional simulation model developed by varying the plate thickness. A. The rate of methanol evaporation was measured using Darcy's law. The rate of methanol evaporation was found to be inversely proportional to the plate thickness, where the decrease in thickness inevitably lowers the resistance along the plate and consequently increases the methanol transport through the plate. This shows that the plate thickness has a significant influence on the rate of methanol evaporation and thereby plays an important role in improving the performance of the passive vapor-feed direct methanol fuel cell.

  5. Effect of microchannel structure on the reaction performance of methanol steam reforming

    International Nuclear Information System (INIS)

    Pan, Minqiang; Wu, Qiuyu; Jiang, Lianbo; Zeng, Dehuai

    2015-01-01

    Highlights: • Effect of microchannel cross-section and distribution on MSR are investigated. • Microchannel distribution shows much more influence on reaction performance. • SLDR and ELR with rectangular cross-section present better reaction performance. • DLSR and EUU with tooth cross-section have better reaction performance. • Equal-distribution of microchannels present the best reaction performance. - Abstract: Methanol steam reforming inside microchannel reactors is regarded as one of effective methods for supplying hydrogen for fuel cells. Microchannel structure plays an important role on the reaction performance of methanol steam reforming. Parallel and uniform-distributed microchannels with rectangular cross-section are generally adopted. In this work, two kinds of microchannel cross-sections and four kinds of microchannel distributions are selected to investigate the effect of microchannel structure on the reaction performance of methanol steam reforming. The result indicates that microchannel distribution shows much more influences on the reaction performance of methanol steam reforming than the microchannel cross-section. Sparse-distribution in the Left direction and Dense-distribution in the Right direction (SLDR) as well as Equal-distribution in the Left–Right direction (ELR) with rectangular cross-section present relatively good reaction performances, whereas Dense-distribution in the Left direction and Sparse-distribution in the Right direction (DLSR) as well as Equal-distribution in the Upside–Underside direction (EUU) with tooth cross-section have relatively good performances. ELR presents the best reaction performances of methanol steam reforming among all the investigated microchannel structures, whether rectangular or tooth cross-section

  6. Effect of pervaporation plate thickness on the rate of methanol evaporation in a passive vapor-feed direct methanol fuel cell

    International Nuclear Information System (INIS)

    Fauzi, N F I; Hasran, U A; Kamarudin, S K

    2015-01-01

    In a passive vapor-feed direct methanol fuel cell (DMFC), methanol vapor is typically obtained using a pervaporation plate in a process by which liquid methanol contained in the fuel reservoir undergoes a phase change to vapor in the anodic vapor chamber. This work investigates the effect of pervaporation plate thickness on the rate of methanol evaporation using a three-dimensional simulation model developed by varying the plate thickness. A. The rate of methanol evaporation was measured using Darcy's law. The rate of methanol evaporation was found to be inversely proportional to the plate thickness, where the decrease in thickness inevitably lowers the resistance along the plate and consequently increases the methanol transport through the plate. This shows that the plate thickness has a significant influence on the rate of methanol evaporation and thereby plays an important role in improving the performance of the passive vapor-feed direct methanol fuel cell. (paper)

  7. A Numerical Study on Mass Transfer and Methanol Conversion Efficiency According to Porosity and Temperature Change of Curved Channel Methanol-Steam Reformer

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Hong Seok; Lee, Chung Ho; Suh, Jeong Se [Gyeongsang Nat’l Univ., Jinju (Korea, Republic of)

    2016-11-15

    Micro methanol-steam reformer for fuel cell can effectively produce hydrogen as reforming response to steam takes place in low temperature (less than 250℃). This study conducted numerical research on this reformer. First, study set wall temperature of the reformer at 100, 140, 180 and 220℃ while methanol conversion efficiency was set in 0, 0.072, 3.83 and 46.51% respectively. Then, porosity of catalyst was set in 0.1, 0.35, 0.6 and 0.85 and although there was no significant difference in methanol conversion efficiency, values of pressure drop were 4645.97, 59.50, 5.12 and 0.45 kPa respectively. This study verified that methanol-steam reformer rarely responds under the temperature of 180℃ and porosity does not have much effect on methanol conversion efficiency if the fluid flowing through reformer lowers activation energy by sufficiently contacting reformer.

  8. A Numerical Study on Mass Transfer and Methanol Conversion Efficiency According to Porosity and Temperature Change of Curved Channel Methanol-Steam Reformer

    International Nuclear Information System (INIS)

    Seong, Hong Seok; Lee, Chung Ho; Suh, Jeong Se

    2016-01-01

    Micro methanol-steam reformer for fuel cell can effectively produce hydrogen as reforming response to steam takes place in low temperature (less than 250℃). This study conducted numerical research on this reformer. First, study set wall temperature of the reformer at 100, 140, 180 and 220℃ while methanol conversion efficiency was set in 0, 0.072, 3.83 and 46.51% respectively. Then, porosity of catalyst was set in 0.1, 0.35, 0.6 and 0.85 and although there was no significant difference in methanol conversion efficiency, values of pressure drop were 4645.97, 59.50, 5.12 and 0.45 kPa respectively. This study verified that methanol-steam reformer rarely responds under the temperature of 180℃ and porosity does not have much effect on methanol conversion efficiency if the fluid flowing through reformer lowers activation energy by sufficiently contacting reformer.

  9. PdZnAl Catalysts for the Reactions of Water-Gas-Shift, Methanol Steam Reforming, and Reverse-Water-Gas-Shift

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A.; Platon, Alexandru; Datye, Abhaya K.; Vohs, John M.; Wang, Yong; Palo, Daniel R.

    2008-03-07

    Pd/ZnO/Al2O3 catalysts were studied for water-gas-shift (WGS), methanol steam reforming, and reverse-water-gas-shift (RWGS) reactions. WGS activity was found to be dependent on the Pd:Zn ratio with a maximum activity obtained at approximately 0.50, which was comparable to that of a commercial Pt-based catalyst. The catalyst stability was demonstrated for 100 hours time-on-stream at a temperature of 3600C without evidence of metal sintering. WGS reaction rates were approximately 1st order with respect to CO concentration, and kinetic parameters were determined to be Ea = 58.3 kJ mol-1 and k0 = 6.1x107 min-1. During methanol steam reforming, the CO selectivities were observed to be lower than the calculated equilibrium values over a range of temperatures and steam/carbon ratios studied while the reaction rate constants were approximately of the same magnitude for both WGS and methanol steam reforming. These results indicate that although Pd/ZnO/Al2O3 are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS rate constants are on the order of about 20 times lower than that of methanol steam reforming, suggesting that RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming.

  10. Hydrogen production by steam reforming methanol for polymer electrolyte fuel cells

    International Nuclear Information System (INIS)

    Amphlett, J.C.; Creber, K.A.M.; Davis, J.M.; Mann, R.F.; Peppley, B.A.; Stokes, D.M.

    1993-01-01

    Catalytic steam reforming of methanol has been studied as a means of generating hydrogen for a polymer electrolyte membrane fuel cell. A semi-empirical model of the kinetics of the catalytic steam reforming of methanol over Cu O/Zn O/Al 2 O 3 catalyst has been developed. This model is able to predict the performance of the reformer with respect to the various parameters important in developing an integrated reformer-polymer fuel cell system. A set of sample calculations of reformer temperature and CO production are given. The impact of the performance of the reformer catalyst on the design of the overall fuel cell power system is discussed. The selectivity of the catalyst to minimize CO content in the fuel gas is shown to be more critical than was previously believed. 4 figs., 4 tabs., 11 refs

  11. Steam reforming and oxidative steam reforming of methanol over CuO-CeO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Udani, P.P.C.; Gunawardana, P.V.D.S.; Lee, Hyun Chan; Kim, Dong Hyun [Department of Chemical Engineering, Kyungpook National University, Daegu 702-701 (Korea)

    2009-09-15

    Steam reforming (SRM) and oxidative steam reforming of methanol (OSRM) were carried out over a series of coprecipitated CuO-CeO{sub 2} catalysts with varying copper content in the range of 30-80 at.% Cu (= 100 x Cu/(Cu + Ce)). The effects of copper content, reaction temperature and O{sub 2} concentration on catalytic activity were investigated. The activity of CuO-CeO{sub 2} catalysts for SRM and OSRM increased with the copper content and 70 at.% CuO-CeO{sub 2} catalyst showed the highest activity in the temperature range of 160-300 C for both SRM and OSRM. After SRM or OSRM, the copper species in the catalysts observed by XRD were mainly metallic copper with small amount of CuO and Cu{sub 2}O, an indication that metallic copper is an active species in the catalysis of both SRM and OSRM. It was observed that the methanol conversion increased considerably with the addition of O{sub 2} into the feed stream, indicating that the partial oxidation of methanol (POM) is much faster than SRM. The optimum 70 at.% CuO-CeO{sub 2} catalyst showed stable activities for both SRM and OSRM reactions at 300 C. (author)

  12. Development of methanol evaporation plate to reduce methanol crossover in a direct methanol fuel cell

    Science.gov (United States)

    Zhang, Ruiming

    This research focuses on methanol crossover reduction in direct methanol fuel cells (DMFC) through separating the methanol vapor from its liquid phase and feeding the vapor passively at low temperature range. Membrane electrode assemblies (MEAs) were fabricated by using commercial available membrane with different thickness at different anode catalyst loading levels, and tested under the operating conditions below 100°C in cell temperature and cathode exit open to ambient pressure. Liquid methanol transport from the anode through the membrane into cathode ("methanol crossover") is identified as one of the major efficiency losses in a DMFC. It is known that the methanol crossover rate in the vapor phase is much lower than in liquid phase. Vapor feed can be achieved by heating the liquid methanol to elevated temperatures (>100°C), but other issues limit the performance of the cell when operating above 100°C. High temperature membranes and much more active cathode catalyst structures are required, and a complex temperature control system must be employed. However, methanol vapor feed can also occur at a lower temperature range (evaporation through a porous body. The methanol crossover with this vapor feed mode is lower compared with the direct liquid methanol feed. A new method of using a methanol evaporation plate (MEP) to separate the vapor from its liquid phase to reduce the liquid methanol crossover at low temperature range is developed. A MEP plays the roles of liquid/vapor methanol phase separation and evaporation in a DMFC. The goal of this study is to develop a MEP with the proper properties to achieve high methanol phase separation efficiency and fast methanol evaporation rate over a wide range of temperature, i.e., from room temperature up to near boiling temperature (100°C). MEP materials were selected and characterized. MEPs made from three different types were tested extensively with different MEA and porous back layer configurations. The benefits of

  13. Effect of a diffuser on performance enhancement of a cylindrical methanol steam reformer by computational fluid dynamic analysis

    International Nuclear Information System (INIS)

    Perng, Shiang-Wuu; Horng, Rong-Fang; Wu, Horng-Wen

    2017-01-01

    Highlights: •We enhance performance of a cylindrical MSR to get higher net power of fuel cell. •We study diffuser angle and length and wall temperature on net power of fuel cell. •We study methanol conversion, hydrogen production, CO of a novel reformer. •Diffuser in catalyst bed upstream raises methanol conversion, hydrogen production. •The MSR raises hydrogen production up to 44.6% and net fuel cell power up to 24.6%. -- Abstract: Proton exchange membrane fuel cells (PEMFC) connected with a methanol steam reformer designed to enhance its performance is considered as a promising future power source. Enhancing the performance of a cylindrical methanol steam reformer due to diffuser effects was then investigated applying three-dimensional computational fluid dynamics by the SIMPLE-C algorithm and an Arrhenius form of reaction model. The effect of the angle and length of the diffuser, and wall temperature have been explored on heat and fluid flow, methanol conversion, hydrogen production, carbon monoxide reduction, as well as estimated net power of fuel cell with the same catalyst volume and entrance condition in a cylindrical methanol steam reformer. The results indicate that the diffuser obviously enhances methanol conversion and hydrogen production of a cylindrical methanol steam reformer. In comparison with a traditional reformer, the reformer with a diffuser of θ d = 6° and L d = 75 mm obtains the maximum enhancement of 22.96% in methanol conversion, 44.62% in hydrogen production, and 24.59% in estimated net power of fuel cell at wall temperature of 250 °C. In addition, the novel reformer with a diffuser of θ d = 9° and L d = 100 mm generates the maximum reduction of 44.17% in CO production at T W = 250 °C.

  14. Acoustic tool for leak inspections in steam generator divider plates

    International Nuclear Information System (INIS)

    Kowalewski, J.; Maak, P.; Colbert, M.

    1997-01-01

    Cross flow leakage through divider plates in the primary head of steam generators, may be a contributor to RIHT rise which can have a negative effect on the operation of a plant. A method to provide quick and reliable inspection of divider plate leakage can be very useful in helping make timely and effective maintenance decisions. A novel acoustic tool for performing inspections in drained steam generators during shutdowns has been developed by OH Technologies and successfully demonstrated in a field application. The technique, referred as ALIS (acoustic leak inspection system), performs a scan of the divider plate face and presents a graphic image of the leakage paths and an estimate of the total leakage area. (author)

  15. A dense Pd/Ag membrane reactor for methanol steam reforming: Experimental study

    NARCIS (Netherlands)

    Basile, A.; Gallucci, F.; Paturzo, L.

    2005-01-01

    This paper focuses on an experimental study of the methanol steam reforming (MSR) reaction. A dense Pd/Ag membrane reactor (MR) has been used, and its behaviour has been compared to the performance of a traditional reactor (TR) packed with the same catalyst type and amount. The parameters

  16. Improving electron beam weldability of heavy steel plates for PWR-steam generator

    International Nuclear Information System (INIS)

    Tomita, Yukio; Mabuchi, Hidesato; Koyama, Kunio

    1996-01-01

    Installation and replacement of many PWR-steam generators are planned inside and outside Japan. The steel plates for steam generators are heavy in thickness, and increase the number of welding passes and prolong the welding time. Electron beam welding (EBW) can greatly reduce the welding period compared with conventional welding methods (narrow-gap gas metal arc welding (GMAW) and submerged arc welding (SAW)). The problems in applying EBW are to prevent weld defects and to improve the toughness of the weld metal. Defect-free welding procedures were successfully established even in thick steel plates. The factors that deteriorate weld-metal (WM) toughness of EBW were investigated. The manufacturing process, which utilizes a new secondary refining process at steelmaking and a high-torque mill at plate mill in actual mass-production, were established. EBW base metal and WM have better properties including fracture toughness than those of conventional welding processes. As a result, an application of EBW to the fabrication of PWR-steam generators has become possible. Large amounts of ASTM A533 Gr B Cl 2 (JIS SQV2B) steel plates in actual PWR-steam generators have come to be produced (more than 1,500 ton) by applying EBW. (author)

  17. Hydrogen Production from Methanol Steam Reforming over TiO2 and CeO2 Pillared Clay Supported Au Catalysts

    Directory of Open Access Journals (Sweden)

    Rongbin Zhang

    2018-01-01

    Full Text Available Abstract: Methanol steam reforming is a promising process for the generation of hydrogen. In this study, Au catalysts supported on modified montmorillonite were prepared and their catalytic activity for methanol steam reforming was investigated at 250–500 °C. The physical and chemical properties of the as-prepared catalysts were characterized by Brunauer–Emmet–Teller method (BET, X-ray diffraction (XRD, transmission electron microscopic (TEM, scanning electron microscopy (SEM, X-ray photoelectron spectroscopy (XPS, Inductively Coupled Plasma (ICP, and thermogravimetrc analysis (TGA. For the catalysts examined, Au-Ti-Ce/Na-ABen exhibits the best catalytic performance with methanol conversion of 72% and H2 selectivity of 99% at 350 °C. This could be attributed to Au, Ce, and Ti species which form a solid solution and move into the interlayer space of the bentonite leading to a high surface area, large average pore volume, large average pore diameter, and small Au particle size. We considered that the synergistic effect of the crosslinking agent, the Ce species, and the Au active sites were responsible for the high activity of Au-Ti-Ce/Na-ABen catalyst for methanol steam reforming.

  18. Viewing device of a steam generator tube-plate

    International Nuclear Information System (INIS)

    Denis, J.; Poirier, D.

    1984-01-01

    The invention proposes a device to observe the tubular plate of a steam generator including rows of parallel tubes situated in a shell provided with at least one entrance situated face to the interval between two adjacent rows. The device comprises a boom of which transversal dimension is less important than the interval; the boom can be inserted by the entrance; it contains a rigid endoscope terminated in an eyepiece and an optical fibre lighguide in the same vertical plane for illumination of the far end. The respective rotary angled mirrors are driven simultaneously by drums connected to a rack-and-pinion mechanism which is operated by a plunger held by a spring against a rocking lever driven by a motor and cam. As the mirrors rotate, the illuminated zone overlaps the field of view of the endoscope. The tube plate area in the shadow of the endoscope mirror (20) is illuminated separately by an ailiary fibre with a fixed terminal mirror. The invention enables the observation of the tube plate on both sides of the boom. It can be used in the case of the inspection of the steam generator of a pressurized water reactor [fr

  19. Proceedings of steam generator sludge deposition in recirculating and once through steam generator upper tube bundle and support plates

    International Nuclear Information System (INIS)

    Baker, R.L.; Harvego, E.A.

    1992-01-01

    The development of remedial measures of shot peening have given nuclear utilities viable measures to address primary water stress corrosion cracking to extend steam generator life. The nuclear utility industry is now faced with potential replacement of steam generators in nuclear power plants due to stress corrosion cracking and intergranular attach in crevice locations on the secondary side of steam generators at tube support plates and at the crevice at the top of the tube sheet. Significant work has been done on developing and understanding of the effects of sludge buildup on the corrosion process at these locations. This session was envisioned to provide a forum for the development of an understanding of the mechanisms which control the transport and deposition of sludge on the secondary side of steam generators. It is hoped that this information will aid utilities in monitoring the progression of fouling of these crevices by further knowledge in where to look for the onset of support plate crevice fouling. An understanding of the progression of fouling from upper tube support plates to those lower in the steam generator where higher temperatures cause the corrosion process to initiate first can aid the nuclear utility industry in developing remedial measures for this condition and in providing a forewarning of when to apply such remedial measures

  20. Methanol steam-reforming in a catalytic fixed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Duesterwald, H G; Hoehlein, B; Kraut, H; Meusinger, J; Peters, R [Research Centre Juelich (KFA) (Germany). Inst. of Energy Process Engineering; Stimming, U [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Festkoerperphysik und Techn. Phys.

    1997-12-01

    Designing an appropriate methanol steam reformer requires detailed knowledge about the processes within such a reactor. Thus, the axial temperature and concentration gradients and catalyst ageing were investigated. It was found that for a fresh catalyst load, the catalyst located in the reactor entrance was most active during the experiment. The activity of this part of the catalyst bed decreased after some time of operation due to ageing. With further operation, the most active zone moved through the catalyst bed. From the results concerning hydrogen production and catalyst degradation, the necessary amount of catalyst for a mobile PEMFC-system can be estimated. (orig.)

  1. Application of flexible micro temperature sensor in oxidative steam reforming by a methanol micro reformer.

    Science.gov (United States)

    Lee, Chi-Yuan; Lee, Shuo-Jen; Shen, Chia-Chieh; Yeh, Chuin-Tih; Chang, Chi-Chung; Lo, Yi-Man

    2011-01-01

    Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS) technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM), with the relevant parameters optimized as well.

  2. Application of Flexible Micro Temperature Sensor in Oxidative Steam Reforming by a Methanol Micro Reformer

    Directory of Open Access Journals (Sweden)

    Yi-Man Lo

    2011-02-01

    Full Text Available Advances in fuel cell applications reflect the ability of reformers to produce hydrogen. This work presents a flexible micro temperature sensor that is fabricated based on micro-electro-mechanical systems (MEMS technology and integrated into a flat micro methanol reformer to observe the conditions inside that reformer. The micro temperature sensor has higher accuracy and sensitivity than a conventionally adopted thermocouple. Despite various micro temperature sensor applications, integrated micro reformers are still relatively new. This work proposes a novel method for integrating micro methanol reformers and micro temperature sensors, subsequently increasing the methanol conversion rate and the hydrogen production rate by varying the fuel supply rate and the water/methanol ratio. Importantly, the proposed micro temperature sensor adequately controls the interior temperature during oxidative steam reforming of methanol (OSRM, with the relevant parameters optimized as well.

  3. Remarkable support effect on the reactivity of Pt/In2O3/MOx catalysts for methanol steam reforming

    Science.gov (United States)

    Liu, Xin; Men, Yong; Wang, Jinguo; He, Rong; Wang, Yuanqiang

    2017-10-01

    Effects of supports over Pt/In2O3/MOx catalysts with extremely low loading of Pt (1 wt%) and In2O3 loadings (3 wt%) are investigated for the hydrogen production of methanol steam reforming (MSR) in the temperature range of 250-400 °C. Under practical conditions without the pre-reduction, the 1Pt/3In2O3/CeO2 catalyst shows the highly efficient catalytic performance, achieving almost complete methanol conversion (98.7%) and very low CO selectivity of 2.6% at 325 °C. The supported Pt/In2O3 catalysts are characterized by means of Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), high-resolution transmission microscopy (HRTEM), temperature programmed reduction with hydrogen (H2-TPR), CO pulse chemisorption, temperature programmed desorption of methanol and water (CH3OH-TPD and H2O-TPD). These demonstrate that the nature of catalyst support of Pt/In2O3/MOx plays crucial roles in the Pt dispersion associated by the strong interaction among Pt, In2O3 and supporting materials and the surface redox properties at low temperature, and thus affects their capability to activate the reactants and determines the catalytic activity of methanol steam reforming. The superior 1Pt/3In2O3/CeO2 catalyst, exhibiting a remarkable reactivity and stability for 32 h on stream, demonstrates its potential for efficient hydrogen production of methanol steam reforming in mobile and de-centralized H2-fueled PEMFC systems.

  4. Effect of microwave double absorption on hydrogen generation from methanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Hsin; Lin, Bo-Jhih [Department of Greenergy, National University of Tainan, Tainan 700 (China)

    2010-03-15

    Hydrogen generation from steam reforming of methanol (SRM) with a CuO/ZnO/Al{sub 2}O{sub 3} catalyst was investigated in the study; particular emphasis was placed on the reactions of SRM exposed to an environment with microwave irradiation. By virtue of the double absorption of microwaves by both the reagents and the catalyst, the experiments suggested that the SRM could be heated and triggered rapidly within a short time, and the methanol conversion from SRM with microwave heating was high compared to that with conventional heating. The obtained results also indicated that, when the reaction temperature was as high as 250 C, thermodynamic equilibrium governed the SRM, whereas the reaction was kinetically controlled for the temperature lower than 250 C. Contrary to Le Chatelier's principle, it was noted that an increase in S/C ratio decreased methanol conversion. This can be explained by the fact that water absorbs microwave irradiation stronger than methanol. The performance of the SRM was evaluated based on the carbon conservation method and the nitrogen tracer method. It was found that the latter was also capable of providing an accurate prediction on methanol conversion, even though the flow rate of the product gas was not measured. (author)

  5. A novel back-up control structure to manage nonroutine steam upsets in industrial methanol distillation columns

    DEFF Research Database (Denmark)

    Udugama, Isuru A.; Zander, Cornina; Mansouri, Seyed Soheil

    2017-01-01

    Industrial methanol production plants have extensive heat integration to achieve energy efficient operations where steam generated from these heat integration operations are used to provide reboiler duty for methanol distillation columns that purify crude methanol produced into industrial AA grade...... supervisory layer to control the column during these non-routine process upsets. These control schemes were tested against realistic reboiler duty disturbances that can occur in an industrial process. The tests revealed that both the MPC and supervisory systems control structures are able to regulate...... the process, even during sudden drops in reboiler duty. However, the cost of implementation and the relative simplicity will likely favour the implementation of the supervisory control structure in an industrial environment....

  6. Explosively free-formed pass partition plate for a nuclear steam generator

    International Nuclear Information System (INIS)

    Schroeder, J.W.

    1980-01-01

    A large flow-separating dished plate of a complex shape was manufactured by near-contact explosive forming in which only an edge die was used. The shape of the part, for service in a large, nuclear steam generator, was obtained by careful sizing and placement of the explosive charge. The development of the technique and the manufacture of the plate are described. 4 refs

  7. Synthesis and Activity Test of Cu/ZnO/Al2O3 for the Methanol Steam Reforming as a Fuel Cell’s Hydrogen Supplier

    Directory of Open Access Journals (Sweden)

    IGBN Makertihartha

    2009-05-01

    Full Text Available The synthesis of hydrogen from hydrocarbons through the steam reforming of methanol on Cu/ZnO/Al2O3 catalyst has been investigated. This process is assigned to be one of the promising alternatives for fuel cell hydrogen process source. Hydrogen synthesis from methanol can be carried out by means of methanol steam reforming which is a gas phase catalytic reaction between methanol and water. In this research, the Cu/ZnO/Al2O3 catalyst prepared by the dry impregnation was used. The specific surface area of catalyst was 194.69 m2/gram.The methanol steam reforming (SRM reaction was carried out by means of the injection of gas mixture containing methanol and water with 1:1.2 mol ratio and 20-90 mL/minute feed flow rate to a fixed bed reactor loaded by 1 g of catalyst. The reaction temperature was 200-300 °C, and the reactor pressure was 1 atm. Preceding the reaction, catalyst was reduced in the H2/N2 mixture at 160 °C. This study shows that at 300 °C reaction temperature, methanol conversion reached 100% at 28 mL/minute gas flow rate. This conversion decreased significantly with the increase of gas flow rate. Meanwhile, the catalyst prepared for SRM was stable in 36 hours of operation at 260 °C. The catalyst exhibited a good stability although the reaction condition was shifted to a higher gas flow rate.

  8. Support and tool displacement device for the attachment of a tube bundle on a tubular plate of a steam generator

    International Nuclear Information System (INIS)

    Morisot, M.; Werle, R.; Michaud, J.P.

    1983-01-01

    The steam generator is being assembled, disposed with its axis horizontal and its tubular plate vertical; the device described in this patent, allows to automatize the preparation stages of the tubular plate and the attachment of the bundle, to shorten the construction of the steam generator and to remove drudgeries done by hand on the tubular plate or the tubes of the bundle. The invention can be applied to the construction of PWR steam generators [fr

  9. Visual Inspection of the Flow Distribution Plate Bolts of a Nuclear Steam Generator

    International Nuclear Information System (INIS)

    Jeong, Woo Tae; Kim, Suk Tae; Sohn, Wook; Kang, Duk Won; Kang, Seok Chul

    2007-01-01

    To develop a system for visually inspecting the flow distribution plate (FDP) bolts of a nuclear steam generator, we reviewed several types of similar inspection equipment. The equipment which are currently available are mostly for inspecting lower part of a steam generator such as tube sheets and annulus except ELVS (Eggcrate Visual Inspection System). However, the design concept of ELVS could not be used for developing a device which enables the visual inspection of flow distribution plate bolts. Therefore, based on the current state of the art technology on the similar equipment, we conceptually designed a new inspection system for checking the FDP bolts

  10. Poly-dimethylsiloxane (PDMS) based micro-reactors for steam reforming of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ji Won; Kundu, Arunabha; Jang, Jae Hyuk

    2010-11-15

    A miniaturized methanol steam reformer with a serpentine type of micro-channels was developed based on poly-dimethylsiloxane (PDMS) material. This way of fabricating micro-hydrogen generator is very simple and inexpensive. The volume of a PDMS micro-reformer is less than 10 cm{sup 3}. The catalyst used was a commercial Cu/ZnO/Al{sub 2}O{sub 3} reforming catalyst from Johnson Matthey. The Cu/ZnO/Al{sub 2}O{sub 3} reforming catalyst particles of mean diameter 50-70 {mu}m was packed into the micro-channels by injecting water based suspension of catalyst particles at the inlet point. The miniaturized PDMS micro-reformer was operated successfully in the operating temperatures of 180-240 C and 15%-75% molar methanol conversion was achieved in this temperature range for WHSV of 2.1-4.2 h{sup -1}. It was not possible to operate the micro-reformer made by pure PDMS at temperature beyond 240 C. Hybrid type of micro-reformer was fabricated by mixing PDMS and silica powder which allowed the operating temperature around 300 C. The complete conversion (99.5%) of methanol was achieved at 280 C in this case. The maximum reformate gas flow rate was 30 ml/min which can produce 1 W power at 0.6 V assuming hydrogen utilization of 60%. (author)

  11. Vertical steam generator with slab-type tube-plate with even tube bundle washing

    International Nuclear Information System (INIS)

    Manek, O.; Masek, V.; Motejl, V.; Quitta, R.

    1980-01-01

    A shielding plate supporting the tubes attached to the tube plate of a vertical steam generator is mounted above the tube plate. Tube sleeves are designed with a dimensional tolerance relative to the heat transfer tubes and the sleeve end and the tube plate end. A separate space is thus formed above the tube plate in which circulation or feed water is introduced to flow between the branch and the heat transfer tube. This provides intensive washing of heat transfer tubes at a critical point and prevents deposit formation, thus excluding heat transfer tube failures. (J.B.)

  12. Methanol from biomass and hydrogen

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    For Hawaii in the near term, the only liquid fuels indigenous sources will be those that can be made from biomass, and of these, methanol is the most promising. In addition, hydrogen produced by electrolysis can be used to markedly increase the yield of biomass methanol. This paper calculates cost of producing methanol by an integrated system including a geothermal electricity facility plus a plant producing methanol by gasifying biomass and adding hydrogen produced by electrolysis. Other studies cover methanol from biomass without added hydrogen and methanol from biomass by steam and carbon dioxide reforming. Methanol is made in a two-step process: the first is the gasification of biomass by partial oxidation with pure oxygen to produce carbon oxides and hydrogen, and the second is the reaction of gases to form methanol. Geothermal steam is used to generate the electricity used for the electrolysis to produce the added hydrogen

  13. Synthesis and Characterization of 1D Ceria Nanomaterials for CO Oxidation and Steam Reforming of Methanol

    Directory of Open Access Journals (Sweden)

    Sujan Chowdhury

    2011-01-01

    Full Text Available Novel one-dimensional (1D ceria nanostructure has been investigated as a promising and practical approach for the reforming of methanol reaction. Size and shape of the ceria nanomaterials are directly involved with the catalytic activities. Several general synthesis routes as including soft and hard template-assemble phenomenon for the preparation of 1D cerium oxide are discussed. This preparation phenomenon is consisting with low cost and ecofriendly. Nanometer-sized 1D structure provides a high-surface area that can interact with methanol and carbon-monoxide reaction. Overall, nanometer-sized structure provides desirable properties, such as easy recovery and regeneration. As a result, the use of 1D cerium has been suitable for catalytic application of reforming. In this paper, we describe the 1D cerium oxide syntheses route and then summarize their properties in the field of CO oxidation and steam reforming of methanol approach.

  14. Hydrogen production by methanol steam reforming carried out in membrane reactor on Cu/Zn/Mg-based catalyst

    NARCIS (Netherlands)

    Basile, A.; Parmaliana, A.; Tosti, S.; Iulianelli, A.; Gallucci, F.; Espro, C.; Spooren, J.

    2008-01-01

    The methanol steam reforming (MSR) reaction was studied by using both a dense Pd-Ag membrane reactor (MR) and a fixed bed reactor (FBR). Both the FBR and the MR were packed with a new catalyst based on CuOAl2O3ZnOMgO, having an upper temperature limit of around 350 °C. A constant sweep gas flow rate

  15. Experimental results of the consequences of sodium water reactions at the bottom tube plate region of straight tube steam generators

    International Nuclear Information System (INIS)

    Ruloff, G.

    1990-01-01

    Experience with sodium water reactions has shown, that the course of such a steam generator accident depends strongly on its place in the steam generator. For the EFR steam generators we have to differentiate between: weld region at the upper tube plate (gas space); bundle region; weld region at the bottom tube plate. This paper describes results of a running tests program simulating the bottom tube plate area. One main part of these tests is the investigation of the influence of wastage protection shrouds between the tubes in the weld region to avoid a fast leak propagation and to give time for leak detection and mastering of the accidents. (author). 10 figs, 2 tabs

  16. Zircon Supported Copper Catalysts for the Steam Reforming of Methanol

    Science.gov (United States)

    Widiastri, M.; Fendy, Marsih, I. N.

    2008-03-01

    Steam reforming of methanol (SRM) is known as one of the most favorable catalytic processes for producing hydrogen. Current research on zirconia, ZrO2 supported copper catalyst revealed that CuO/ZrO2 as an active catalyst for the SRM. Zircon, ZrSiO4 is available from the by-product of tin mining. In the work presented here, the catalytic properties of CuO/ZrSiO4 with various copper oxide compositions ranging from 2.70% (catalyst I), 4.12% (catalyst II), and 7.12%-mass (catalyst III), synthesized by an incipient wetness impregnation technique, were investigated to methanol conversion, selectivity towards CO formation, and effect of ZnO addition (7.83%CuO/8.01%ZnO/ZrSiO4 = catalyst V). The catalytic activity was obtained using a fixed bed reactor and the zircon supported catalyst activity was compared to those of CuO/ZnO/Al2O3 catalyst (catalyst IV) and commercial Kujang LTSC catalyst. An X-ray powder diffraction (XRD) analysis was done to identify the abundant phases of the catalysts. The catalysts topography and particle diameter were measured with scanning electron microscopy (SEM) and composition of the catalysts was measured by SEM-EDX, scanning electron microscope-energy dispersive using X-ray analysis. The results of this research provide information on the possibility of using zircon (ZrSiO4) as solid support for SRM catalysts.

  17. CFD evaluation on the thermohydraulic characteristics of tube support plates in steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.; Zhang, H.; Han, B.; Yang, B.W. [Xi' an Jiaotong Univ. (China). School of Nuclear Science and Technology; Mo, S.J.; Ren, H.B.; Qin, J.M.; Zuo, C.P. [China Nuclear Power Design Co. Ltd., ShenZhen (China)

    2016-07-15

    The integrity and thermal hydraulic characteristics of steam generator are of great concern in the nuclear industry. The tube support plates (TSP), one of the most important components of the steam generator, not only support the heat transfer tubes, but also affect the flow dynamic and thermal hydraulic characteristics of the secondary-side flow inside the steam generator. Different working conditions, ranging from single-phase adiabatic condition to two-phase high-void boiling condition, are simulated and analyzed. Calculated void fraction, under simple geometry, agrees well with the experiment data whilst the simulated heat transfer coefficient is tremendously close to the empirical correlation. Temperature, void fraction, and velocity distributions in different locations show reasonable distribution. The simulation results indicate that TSP can enhance the heat transfer in the secondary side of the steam generator. On the top of TSP, with the increase in cross-section flow area, the back-flow phenomenon occurs, which might lead to the contamination of precipitation.

  18. Process and catalysts for the gasification of methanol. [German Patent

    Energy Technology Data Exchange (ETDEWEB)

    Harris, N.; Dennis, A.J.; Shevels, T.F.

    1975-02-13

    The invention concerns catalysts and catalytic processes for the gasification of methanol which is used to manufacture methane from methanol. Mixtures of iron and chromium oxide, phosphate, phosphoric acid, tungstate, tungstic acid, aluminium phosphate, aluminium oxide are suitable as dehydrating catalysts. Gasification takes place together with steam and dehydrogenating catalysts at high temperature. The molar ratios steam: methanol are described.

  19. Methanol steam reforming over Cu/CeO2 catalysts: influence of zinc addition

    Directory of Open Access Journals (Sweden)

    Franco Tonelli

    2011-01-01

    Full Text Available Methanol steam reforming reaction was studied over Cu(5 wt.%/CeO2 with and without the presence of Zn. The Zn addition decreased the Cu+2 reducibility and increased the oxygen mobility of ceria. The main products were CO2 and H2 with small amount of CO. Selectivity to CO decreased with the Zn addition and it was lower at lower reaction temperatures and lower space velocities. At 230 ºC and W/F MeOH = 648 g min mol-1 selectivities to H2 and to CO2 were 100% on Zn/Cu/Ce. The catalytic results indicated that CO was mainly a secondary product formed from reverse water gas shift reaction.

  20. Bi-reforming of methane from any source with steam and carbon dioxide exclusively to metgas (CO-2H2) for methanol and hydrocarbon synthesis.

    Science.gov (United States)

    Olah, George A; Goeppert, Alain; Czaun, Miklos; Prakash, G K Surya

    2013-01-16

    A catalyst based on nickel oxide on magnesium oxide (NiO/MgO) thermally activated under hydrogen is effective for the bi-reforming with steam and CO(2) (combined steam and dry reforming) of methane as well as natural gas in a tubular flow reactor at elevated pressures (5-30 atm) and temperatures (800-950 °C). By adjusting the CO(2)-to-steam ratio in the gas feed, the H(2)/CO ratio in the produced syn-gas could be easily adjusted in a single step to the desired value of 2 for methanol and hydrocarbon synthesis.

  1. A Comparative Discussion of the Catalytic Activity and CO2-Selectivity of Cu-Zr and Pd-Zr (Intermetallic Compounds in Methanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Norbert Köpfle

    2017-02-01

    Full Text Available The activation and catalytic performance of two representative Zr-containing intermetallic systems, namely Cu-Zr and Pd-Zr, have been comparatively studied operando using methanol steam reforming (MSR as test reaction. Using an inverse surface science and bulk model catalyst approach, we monitored the transition of the initial metal/intermetallic compound structures into the eventual active and CO2-selective states upon contact to the methanol steam reforming mixture. For Cu-Zr, selected nominal stoichiometries ranging from Cu:Zr = 9:2 over 2:1 to 1:2 have been prepared by mixing the respective amounts of metallic Cu and Zr to yield different Cu-Zr bulk phases as initial catalyst structures. In addition, the methanol steam reforming performance of two Pd-Zr systems, that is, a bulk system with a nominal Pd:Zr = 2:1 stoichiometry and an inverse model system consisting of CVD-grown ZrOxHy layers on a polycrystalline Pd foil, has been comparatively assessed. While the CO2-selectivity and the overall catalytic performance of the Cu-Zr system is promising due to operando formation of a catalytically beneficial Cu-ZrO2 interface, the case for Pd-Zr is different. For both Pd-Zr systems, the low-temperature coking tendency, the high water-activation temperature and the CO2-selectivity spoiling inverse WGS reaction limit the use of the Pd-Zr systems for selective MSR applications, although alloying of Pd with Zr opens water activation channels to increase the CO2 selectivity.

  2. Low Temperature Steam Methane Reforming Over Ni Based Catalytic Membrane Prepared by Electroless Palladium Plating.

    Science.gov (United States)

    Lee, Sang Moon; Hong, Sung Chang; Kim, Sung Su

    2018-09-01

    A Pd/Ni-YSZ porous membrane with different palladium loadings and hydrazine as a reducing reagent was prepared by electroless plating and evaluated for the steam methane reforming activity. The steam-reforming activity of a Ni-YSZ porous membrane was greatly increased by the deposition of 4 g/L palladium in the low-temperature range (600 °C). With an increasing amount of reducing reagent, the Pd clusters were well dispersed on the Ni-YSZ surface and were uniform in size (∼500 nm). The Pd/Ni-YSZ catalytic porous membrane prepared by 1 of Pd/hydrazine ratio possessed an abundant amount of metallic Pd. The optimal palladium loadings and Pd/hydrazine ratio increased the catalytic activity in both the steam-reforming reaction and the Pd dispersion.

  3. Countercurrent air/water and steam/water flow above a perforated plate. Report for October 1978-October 1979

    International Nuclear Information System (INIS)

    Hsieh, C.; Bankoff, S.G.; Tankin, R.S.; Yuen, M.C.

    1980-11-01

    The perforated plate weeping phenomena have been studied in both air/water and steam/cold water systems. The air/water experiment is designed to investigate the effect of geometric factors of the perforated plate on the rate of weeping. A new dimensionless flow rate in the form of H star is suggested. The data obtained are successfully correlated by this H star scaling in the conventional flooding equation. The steam/cold water experiment is concentrated on locating the boundary between weeping and no weeping. The effects of water subcooling, water inlet flow rate, and position of water spray are investigated. Depending on the combination of these factors, several types of weeping were observed. The data obtained at high water spray position can be related to the air/water flooding correlation by replacing the stream flow rate to an effective stream flow rate, which is determined by the mixing efficiency above the plate

  4. Device for removing and recuperating sludge deposited on the tube plate of a steam generator

    International Nuclear Information System (INIS)

    Bes, Louis.

    1982-01-01

    The cleaning device includes a descaling ramp with high pressure jets permanently fixed inside the steam generator, a system for driving the sludge formed towards the centre of the tube plate and a valve for removing the sludge giving into a hollow central column [fr

  5. A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes

    International Nuclear Information System (INIS)

    Krause, T. W.; Babbar, V. K.; Underhill, P. R.

    2014-01-01

    Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators

  6. A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes

    Science.gov (United States)

    Krause, T. W.; Babbar, V. K.; Underhill, P. R.

    2014-02-01

    Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators.

  7. Investigations of a type 316L steam dryer plate material suffering from IGSCC after few years in BWRs

    International Nuclear Information System (INIS)

    Autio, J.M.; Ehrnsten, U.; Pakarinen, J.; Mouginot, R.; Cocco, M.

    2015-01-01

    A steam dryer plate material suffered from intergranular stress corrosion cracking after only one and two years of operation in two BWR plants. Numerous indications were observed on the inner roof plates of the steam dryers adjacent to the support beam welds. The material was Type 316L austenitic stainless steel with carbon content below 0.02%. The material was subjected to detailed investigations using optical microscopy, EBSD/SEM, TEM, hardness and nano-indentation. The material showed macro-segregation through the plate thickness. These bands coincided with the location of delta-ferrite islands indicating non-optimal solution heat treatment. α'-martensite was observed deep in the plate indicating cold deformation after solution annealing. A nonhomogeneous distribution of grain orientation was also observed through the plate thickness. Further, surface deformation, although not extending very deep, was observed using EBSD and surface hardness values above 300 HV when measured using small loads. Although the material fulfills the set requirements, the material characteristics have obviously increased the susceptibility of the material to IGSCC. The paper will discuss the possible role of changes in manufacturing over the years and the challenges in quality definitions in material specifications. (authors)

  8. Micro direct methanol fuel cell with perforated silicon-plate integrated ionomer membrane

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Johansson, Anne-Charlotte Elisabeth Birgitta

    2014-01-01

    This article describes the fabrication and characterization of a silicon based micro direct methanol fuel cell using a Nafion ionomer membrane integrated into a perforated silicon plate. The focus of this work is to provide a platform for micro- and nanostructuring of a combined current collector...... at a perforation ratio of 40.3%. The presented fuel cells also show a high volumetric peak power density of 2 mW cm−3 in light of the small system volume of 480 μL, while being fully self contained and passively feed....... and catalytic electrode. AC impedance spectroscopy is utilized alongside IV characterization to determine the influence of the plate perforation geometries on the cell performance. It is found that higher ratios of perforation increases peak power density, with the highest achieved being 2.5 mW cm−2...

  9. Integrated anode structure for passive direct methanol fuel cells with neat methanol operation

    Science.gov (United States)

    Wu, Huijuan; Zhang, Haifeng; Chen, Peng; Guo, Jing; Yuan, Ting; Zheng, Junwei; Yang, Hui

    2014-02-01

    A microporous titanium plate based integrated anode structure (Ti-IAS) suitable for passive direct methanol fuel cells (DMFCs) fueled with neat methanol is reported. This anode structure incorporates a porous titanium plate as a methanol mass transfer barrier and current collector, pervaporation film for passively vaporizing methanol, vaporous methanol cavity for evenly distributing fuel, and channels for carbon dioxide venting. With the effective control of methanol delivery rate, the Ti-IAS based DMFC allows the direct use of neat methanol as the fuel source. In the meantime, the required water for methanol-oxidation reaction at the anode can also be fully recovered from the cathode with the help of the highly hydrophobic microporous layer in the cathode. DMFCs incorporating this new anode structure exhibit a power density as high as 40 mW cm-2 and a high volumetric energy density of 489 Wh L-1 operating with neat methanol and at 25 °C. Importantly, no obvious performance degradation of the passive DMFC system is observed after more than 90 h of continuous operation. The experimental results reveal that the compact DMFC based on the Ti-IAS exhibits a substantial potential as power sources for portable applications.

  10. Design and simulation experimental study of bracket plates in steam generator for AC600 PWR

    International Nuclear Information System (INIS)

    Zhang Fuyuan; Zhang Wenqi; Ji Quankai; Zeng Xi; Xie Yongyao

    1998-01-01

    Seven-holes type bracket plate at the inlet nozzle and three-holes taper bracket plate at outlet nozzle are designed. According to 'local form and structure change' simulation theory, hydraulic models and simulators for the simulative experiments are designed. Taking water as the medium, the simulative experiments have been completed at the room temperature. The ζ-Re curves (here, ζ is the local pressure loss coefficient at the nozzles after the bracket plates are installed and Re is Reynolds number) have been got. Based on the experimental results, the computation and the analysis have been shown that. If the bracket plates are used in the steam generator (SG) of AC600 PWR, the pressure drop of primary side in the SG is about 14 percent higher than that of the 55/19 B style SG

  11. Integrated methanol synthesis

    International Nuclear Information System (INIS)

    Jaeger, W.

    1982-01-01

    This invention concerns a plant for methanol manufacture from gasified coal, particularly using nuclear power. In order to reduce the cost of the hydrogen circuits, the methanol synthesis is integrated in the coal gasification plant. The coal used is gasified with hydration by means of hydrogen and the crude gas emerging, after cooling and separating the carbon dioxide and hydrogen sulphide, is mixed with the synthetic gas leaving the methane cracking furnace. This mixture is taken to the methanol synthesis and more than 90% is converted into methanol in one pass. The gas mixture remaning after condensation and separation of methanol is decomposed into three fractions in low temperature gas decomposition with a high proportion of unconverted carbon monoxide. The flow of methane is taken to the cracking furnace with steam, the flow of hydrogen is taken to the hydrating coal gasifier, and the flow of carbon monoxide is taken to the methanol synthesis. The heat required for cracking the methane can either be provided by a nuclear reactor or by the coke left after hydrating gasification. (orig./RB) [de

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

    Science.gov (United States)

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

    2014-01-01

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

  13. Hydrogen production with a solar steam–methanol reformer and colloid nanocatalyst

    KAUST Repository

    Lee, Ming-Tsang

    2010-01-01

    In the present study a small steam-methanol reformer with a colloid nanocatalyst is utilized to produce hydrogen. Radiation from a focused continuous green light laser (514 nm wavelength) is used to provide the energy for steam-methanol reforming. Nanocatalyst particles, fabricated by using pulsed laser ablation technology, result in a highly active catalyst with high surface to volume ratio. A small novel reformer fabricated with a borosilicate capillary is employed to increase the local temperature of the reformer and thereby increase hydrogen production. The hydrogen production output efficiency is determined and a value of 5% is achieved. Experiments using concentrated solar simulator light as the radiation source are also carried out. The results show that hydrogen production by solar steam-methanol colloid nanocatalyst reforming is both feasible and promising. © 2009 Professor T. Nejat Veziroglu.

  14. Comparison of steam and ammonia pretreatment for enzymatic hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Mes-Hartree, M.; Dale, B.E.; Craig, W.K.

    1988-11-01

    Aspenwood, wheat straw, wheat chaff and alfalfa stems were treated under pressure with either steam or ammonia. The material was then water or methanol/water extracted. The extent of enzymatic hydrolysis of the cellulose portion of the treated substrates was compared using two different cellulases, a commercial preparation, Celluclast, and those from the fungus Trichoderma harzianum. Both steam and ammonia treatment enhanced the accessibility of the cellulose as measured by hydrolysis. Methanol extraction of steamed material generally reduced the access of the enzyme to the cellulose, whereas methanol extraction of ammonia-treated material increased accessibility. The optimum combinations of pretreatment and extraction method depended on the substrate and on the enzyme system; no treatment suitable for all situations could be selected.

  15. Manipulation robot system based on visual guidance for sealing blocking plate of steam generator

    International Nuclear Information System (INIS)

    Duan Xingguang; Wang Yonggui; Li Meng; Kong Xiangzhan; Liu Qingsong

    2016-01-01

    To reduce labor intensity and irradiation exposure time inside the steam generator during the maintenance period of the nuclear power plant, a blocking plate manipulation robot system, including manipulation robot and pneumatic control console, is developed as an automatic remote-control tool to help staff to complete sealing steam generator primary pipes. The manipulation robot for fastening/loosening bolts utilizes visual guidance for target position, and the recognition algorithm is exerted to extract the bolt center coordinate values from image captured by camera in the procedure. The control strategy based on the position and current feedback is proposed for single bolt operation and whole bolts automatic operation. Meanwhile, the virtual interactive interface and remote monitoring are designed to improve the operability and safety. Finally, the relative experiments have verified the work effectiveness and the future work would be discussed. (author)

  16. Plugging criteria for steam generator tubes with axial cracks near tube support plates

    International Nuclear Information System (INIS)

    Mattar Neto, Miguel

    2000-01-01

    Stress corrosion cracking with intergranular attack occurs on the secondary side of steam generator (SG) tubes where impurities concentrate due to boiling under restricted flow conditions. In the most of cases, it can be called ODSCC (Outer Diameter Stress Corrosion Cracking). The typical locations are areas near support plates, in sludge piles and at top of tubesheet crevices. Though it can also occur on free spans under the relatively thin deposits that build up on the tube surfaces. ODSCC near tube plate supports have been the cause of plugging of many tubes. Thus, studies on SG tubes plugging criteria related to this degradation mechanism are presented in this paper. Th purpose is to avoid unnecessary tube plugging from either safety or reliability standpoint. Based on these studies some conclusions on the plugging criteria and on the difficulties to apply them are addressed. (author)

  17. Experimental study of single- and two-phase flow fields around PWR steam generator tube support plates

    International Nuclear Information System (INIS)

    Bates, J.M.; Stewart, C.W.

    1979-08-01

    Laser-Doppler anemometry (LDA) was used to measure local mean axial velocities and turbulence intnsities at selected locations within a study model dimensionally protypic of an existing PWR steam generator design. The model tube bundle with support plate was installed in a special flow housing that formed part of an isothermal recirculating water flow loop. Flow conditions for this experiment were intended to simulate only typical single-phase flow velocities and were not an attempt to completely model actual steam generator, boiling, two-phase flow conditions. The measurements were performed in water at approximately 85 0 F with test section average velocities of approximately 0.55 and 1.1 fps. These conditions corresponded to Reynolds numbers of approximately 7,000 and approximately 14,000, respectively. Normalized velocity and turbulence intensity ratios are graphically reported. Additional qualitative, photographic investigations of air-water two-phase flows in a PWR steam generator study model were also performed

  18. The influence of walls and upper tie plate slots on the flooding mechanism in fuel elements with and without heat transfer between steam and water

    International Nuclear Information System (INIS)

    Spatz, R.; Mewes, D.

    1989-01-01

    The counter-current flow of steam and water was experimentally investigated for the upper part of a PWR fuel element. The actual geometrical shape of the nuclear equipment was simulated by various types of plates, in which bore holes and slots were arranged in different positions. The experiments were performed with and without an installed, unheated rod bundle below the plates. The water was injected at saturated and subcooled temperatures in order to observe the effects of heat transfer on counter-current flow. With increasing steam velocity the flooding occurs initially in the tie-plate area. If the rod bundle is installed in the flow duct, a part of the downwards flowing water is transported upwards from the region of the upper grid spacer to the plate. Heat transfer between the phases can cause in the counter-current flow region an instable transition from downward to near complete upward directed liquid flow. In comparison to experiments with saturated water injection, flooding occurs at larger steam velocities. Different flooding correlations, which are known from the literature, were compared with the experimental data to appraise their applicability to counter-current flow in the core of PWRs. (orig.)

  19. Energy efficiency of a direct-injection internal combustion engine with high-pressure methanol steam reforming

    International Nuclear Information System (INIS)

    Poran, Arnon; Tartakovsky, Leonid

    2015-01-01

    This article discusses the concept of a direct-injection ICE (internal combustion engine) with thermo-chemical recuperation realized through SRM (steam reforming of methanol). It is shown that the energy required to compress the reformate gas prior to its injection into the cylinder is substantial and has to be accounted for. Results of the analysis prove that the method of reformate direct-injection is unviable when the reforming is carried-out under atmospheric pressure. To reduce the energy penalty resulted from the gas compression, it is suggested to implement a high-pressure reforming process. Effects of the injection timing and the injector's flow area on the ICE-SRM system's fuel conversion efficiency are studied. The significance of cooling the reforming products prior to their injection into the engine-cylinder is demonstrated. We show that a direct-injection ICE with high-pressure SRM is feasible and provides a potential for significant efficiency improvement. Development of injectors with greater flow area shall contribute to further efficiency improvements. - Highlights: • Energy needed to compress the reformate is substantial and has to be accounted for. • Reformate direct-injection is unviable if reforming is done at atmospheric pressure. • Direct-injection engine with high-pressure methanol reforming is feasible. • Efficiency improvement by 12–14% compared with a gasoline-fed engine was shown

  20. Steam generator water lancing

    International Nuclear Information System (INIS)

    Kamler, F.; Schneider, W.

    1992-01-01

    The tubesheet and tube support plate deposits in CANDU steam generators are notable for their hardness. Also notable is the wide variety of steam generator access situations. Because of the sludge hardness and the difficulty of the access, traditional water lancing processes which directed jets from the central tube free lane or from the periphery of the bundle have proven unsuitable. This has led to the need for some very unique inter tube water lancing devices which could direct powerful water jets directly onto the deposits. This type of process was applied to the upper broached plates of the Bruce A steam generators, which had become severely blocked. It has since been applied to various other steam generator situations. This paper describes the flexlance equipment development, qualification, and performance in the various CANDU applications. 4 refs., 2 tabs., 7 figs

  1. Performance evaluation of a proof-of-concept 70 W internal reforming methanol fuel cell system

    Science.gov (United States)

    Avgouropoulos, G.; Schlicker, S.; Schelhaas, K.-P.; Papavasiliou, J.; Papadimitriou, K. D.; Theodorakopoulou, E.; Gourdoupi, N.; Machocki, A.; Ioannides, T.; Kallitsis, J. K.; Kolb, G.; Neophytides, S.

    2016-03-01

    A proof-of-concept 70 W Internal Reforming Methanol Fuel Cell (IRMFC) stack including Balance-of-Plant (BoP) was designed, assembled and tested. Advent TPS® high-temperature, polymer electrolyte membrane electrode assemblies were employed for fuel cell operation at 200 °C. In order to avoid phosphoric acid poisoning of the reformer, the anode electrocatalyst of each cell was indirectly adjoined, via a separation plate, to a highly active CuMnAlOx catalyst coated onto copper foam, which served as methanol reforming layer. The reformer was in-situ converting the methanol/steam feed to the required hydrogen (internal reforming concept) at 200 °C, which was readily oxidized at the anode electrodes. The operation of the IRMFC was supported through a number of BoP components consisting of a start-up subsystem (air blower, evaporator and monolithic burner), a combined afterburner/evaporator device, methanol/water supply and data acquisition units (reactants/products analysis, temperature control, flow control, system load/output control). Depending on the composition of the liquid MeOH/H2O feed streams, current densities up to 0.18 A cm-2 and power output up to 70 W could be obtained with remarkable repeatability. Specific targets for improvement of the efficiency were identified.

  2. Preparation of Cu-Fe-Al-O nanosheets and their catalytic application in methanol steam reforming for hydrogen production

    Science.gov (United States)

    Wang, Leilei; Zhang, Fan; Miao, Dinghao; Zhang, Lei; Ren, Tiezhen; Hui, Xidong; He, Zhanbing

    2017-03-01

    Candidates of precious metal catalysts, prepared in a facile and environmental way and showing high catalytic performances at low temperatures, are always highly desired by industry. In this work, large-scale Cu-Fe-Al-O nanosheets were synthesized by facile dealloying of Al-Cu-Fe alloys in NaOH solution. The composition, microscopic morphology, and crystal structure were respectively investigated using wavelength-dispersive x-ray spectroscopy with an electron probe microanalyzer, scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. Furthermore, we found that the 2D Cu-Fe-Al-O nanosheets gave excellent catalytic performances in hydrogen production by methanol steam reforming at relatively low temperatures, e.g. 513 K.

  3. Liquid metal steam generator

    International Nuclear Information System (INIS)

    Wolowodiuk, W.

    1975-01-01

    A liquid metal heated steam generator is described which in the event of a tube failure quickly exhausts out of the steam generator the products of the reaction between the water and the liquid metal. The steam is generated in a plurality of bayonet tubes which are heated by liquid metal flowing over them between an inner cylinder and an outer cylinder. The inner cylinder extends above the level of liquid metal but below the main tube sheet. A central pipe extends down into the inner cylinder with a centrifugal separator between it and the inner cylinder at its lower end and an involute deflector plate above the separator so that the products of a reaction between the liquid metal and the water will be deflected downwardly by the deflector plate and through the separator so that the liquid metal will flow outwardly and away from the central pipe through which the steam and gaseous reaction products are exhausted. (U.S.)

  4. Characterization of hierarchical α-MoO3 plates toward resistive heating synthesis: electrochemical activity of α-MoO3/Pt modified electrode toward methanol oxidation at neutral pH

    Science.gov (United States)

    Filippo, Emanuela; Baldassarre, Francesca; Tepore, Marco; Guascito, Maria Rachele; Chirizzi, Daniela; Tepore, Antonio

    2017-05-01

    The growth of MoO3 hierarchical plates was obtained by direct resistive heating of molybdenum foils at ambient pressure in the absence of any catalysts and templates. Plates synthesized after 60 min resistive heating typically grow in an single-crystalline orthorhombic structure that develop preferentially in the [001] direction, and are characterized by high resolution transmission electron microscopy, selected area diffraction pattern and Raman-scattering measurements. They are about 100-200 nm in thickness and a few tens of micrometers in length. As heating time proceeds to 80 min, plates of α-MoO3 form a branched structure. A more attentive look shows that primary plates formed at until 60 min could serve as substrates for the subsequent growth of secondary belts. Moreover, a full electrochemical characterization of α-MoO3 plates on platinum electrodes was done by cyclic voltammetric experiments, at pH 7 in phosphate buffer, to probe the activity of the proposed composite material as anode to methanol electro-oxidation. Reported results indicate that Pt MoO3 modified electrodes are appropriate to develop new an amperometric non-enzymatic sensor for methanol as well as to make anodes suitable to be used in direct methanol fuel cells working at neutral pH.

  5. Thermodynamics of Hydrogen Production from Dimethyl Ether Steam Reforming and Hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    T.A. Semelsberger

    2004-10-01

    The thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the process of dimethyl ether (DME) steam reforming were investigated as a function of steam-to-carbon ratio (0-4), temperature (100 C-600 C), pressure (1-5 atm), and product species: acetylene, ethanol, methanol, ethylene, methyl-ethyl ether, formaldehyde, formic acid, acetone, n-propanol, ethane and isopropyl alcohol. Results of the thermodynamic processing of dimethyl ether with steam indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure was observed to shift the equilibrium toward the reactants; increasing the pressure from 1 atm to 5 atm decreased the conversion of dimethyl ether from 99.5% to 76.2%. The order of thermodynamically stable products in decreasing mole fraction was methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol--formaldehyde, formic acid, and acetylene were not observed. The optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.5, a pressure of 1 atm, and a temperature of 200 C. Modeling the thermodynamics of dimethyl ether hydrolysis (with methanol as the only product considered), the equilibrium conversion of dimethyl ether is limited. The equilibrium conversion was observed to increase with temperature and steam-to-carbon ratio, resulting in a maximum dimethyl ether conversion of approximately 68% at a steam-to-carbon ratio of 4.5 and a processing temperature of 600 C. Thermodynamically, dimethyl ether processed with steam can produce hydrogen-rich fuel-cell feeds--with hydrogen concentrations exceeding 70%. This substantiates dimethyl ether as a viable source of hydrogen for PEM fuel cells.

  6. CRBRP steam-generator design evolution

    International Nuclear Information System (INIS)

    Geiger, W.R.; Gillett, J.E.; Lagally, H.O.

    1983-01-01

    The overall design of the CRBRP Steam Generator is briefly discussed. Two areas of particular concern are highlighted and considerations leading to the final design are detailed. Differential thermal expansion between the shell and the steam tubes is accommodated by the tubes flexing in the curved section of the shell. Support of the tubes by the internals structure is essential to permit free movement and minimize tube wear. Special spacer plate attachment and tube hole geometry promote unimpeded axial movement of the tubes by allowing individual tubes to rotate laterally and by providing lateral movement of the spacer plates relative to the adjacent support structure. The water/steam heads of the CRBRP Steam Generator are spherical heads welded to the lower and upper tubesheets. They were chosen principally because they provide a positively sealed system and result in more favorable stresses in the tubesheets when compared to mechanically attached steamheads

  7. Thermodynamic performance analysis of a fuel cell trigeneration system integrated with solar-assisted methanol reforming

    International Nuclear Information System (INIS)

    Wang, Jiangjiang; Wu, Jing; Xu, Zilong; Li, Meng

    2017-01-01

    Highlights: • Propose a fuel cell trigeneration system integrated with solar-assisted methanol reforming. • Optimize the reaction parameters of methanol steam reforming. • Present the energy and exergy analysis under design and off-design work conditions. • Analyze the contributions of solar energy to the trigeneration system. - Abstract: A solar-assisted trigeneration system for producing electricity, cooling, and heating simultaneously is an alternative scheme to improve energy efficiency and boost renewable energy. This paper proposes a phosphoric acid fuel cell trigeneration system integrated with methanol and steam reforming assisted by solar thermal energy. The trigeneration system consists of a solar heat collection subsystem, methanol steam reforming subsystem, fuel cell power generation subsystem, and recovered heat utilization subsystem. Their respective thermodynamic models are constructed to simulate the system input/output characteristics, and energy and exergy efficiencies are employed to evaluate the system thermodynamic performances. The contribution of solar energy to the system is analyzed using solar energy/exergy share. Through the simulation and analysis of methanol and steam reforming reactions, the optimal reaction pressure, temperature, and methanol to water ratio are obtained to improve the flow rate and content of produced hydrogen. The thermodynamic simulations of the trigeneration system show that the system energy efficiencies at the summer and winter design work conditions are 73.7% and 51.7%, while its exergy efficiencies are 18.8% and 26.1%, respectively. When the solar radiation intensity is different from the design work condition, the total energy and exergy efficiencies in winter decrease approximately by 4.7% and 2.2%, respectively, due to the decrease in solar heat collection efficiency. This proposed novel trigeneration system complemented by solar heat energy and methanol chemical energy is favorable for improving the

  8. Numerical simulation of effect of catalyst wire-mesh pressure drop characteristics on flow distribution in catalytic parallel plate steam reformer

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2012-01-01

    Steam reforming of hydrocarbons using a catalytic plate-type-heat-exchanger (CPHE) reformer is an attractive method of producing hydrogen for a fuel cell-based micro combined-heat-and-power system. In this study the flow distribution in a CPHE reformer, which uses a coated wire-mesh catalyst...

  9. Steam reforming of methanol over oxide decorated nanoporous gold catalysts: a combined in situ FTIR and flow reactor study.

    Science.gov (United States)

    Shi, J; Mahr, C; Murshed, M M; Gesing, T M; Rosenauer, A; Bäumer, M; Wittstock, A

    2017-03-29

    Methanol as a green and renewable resource can be used to generate hydrogen by reforming, i.e., its catalytic oxidation with water. In combination with a fuel cell this hydrogen can be converted into electrical energy, a favorable concept, in particular for mobile applications. Its realization requires the development of novel types of structured catalysts, applicable in small scale reactor designs. Here, three different types of such catalysts were investigated for the steam reforming of methanol (SRM). Oxides such as TiO 2 and CeO 2 and mixtures thereof (Ce 1 Ti 2 O x ) were deposited inside a bulk nanoporous gold (npAu) material using wet chemical impregnation procedures. Transmission electron and scanning electron microscopy reveal oxide nanoparticles (1-2 nm in size) abundantly covering the strongly curved surface of the nanoporous gold host (ligaments and pores on the order of 40 nm in size). These catalysts were investigated in a laboratory scaled flow reactor. First conversion of methanol was detected at 200 °C. The measured turn over frequency at 300 °C of the CeO x /npAu catalyst was 0.06 s -1 . Parallel investigation by in situ infrared spectroscopy (DRIFTS) reveals that the activation of water and the formation of OH ads are the key to the activity/selectivity of the catalysts. While all catalysts generate sufficient OH ads to prevent complete dehydrogenation of methanol to CO, only the most active catalysts (e.g., CeO x /npAu) show direct reaction with formic acid and its decomposition to CO 2 and H 2 . The combination of flow reactor studies and in operando DRIFTS, thus, opens the door to further development of this type of catalyst.

  10. Characterization and Modeling of a Methanol Reforming Fuel Cell System

    DEFF Research Database (Denmark)

    Sahlin, Simon Lennart

    topologies is the Reformed Methanol Fuel Cell (RMFC) system that operates on a mix of methanol and water. The fuel is reformed with a steam reforming to a hydrogen rich gas, however with additional formation of Carbon Monoxide and Carbon Dioxide. High Temperature Polymer Electrolyte Membrane Fuel Cell (HT...... to heat up the steam reforming process. However, utilizing the excess hydrogen in the system complicates the RMFC system as the amount of hydrogen can vary depending on the fuel methanol supply, fuel cell load and the reformer gas composition. This PhD study has therefore been involved in investigating......Many fuel cells systems today are operated with compressed hydrogen which has great benefits because of the purity of the hydrogen and the relatively simple storage of the fuel. However, compressed hydrogen is stored in the range of 800 bar, which can be expensive to compress.One of the interesting...

  11. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  12. Steam generators in PWR's

    International Nuclear Information System (INIS)

    Michel, R.

    1974-01-01

    The steam generator of the PWR operates according to the principle of natural circulation. It consists of a U-shaped tube bundle whose free ends are welded to a bottom plate. The tube bundle is surrounded by a cylinder jacket which has slots closely above the bottom or tube plate. The feed water mixed with boiling water enters the tube bundle through these slots. Because of its buoyancy, the steam-water mixture flows upwards. Below the tube plate there are chambers for distributing and collecting pressurized water separated by means of a partition wall. By omitting some tubes, a free alloy is created so that the tubes in the center get sufficient water, too. By asymmetrical arrangement of the partition wall it is further possible to limit the tube alloy only to the inlet side for pressurized water. The flow over the tube plate is thus improved on the inlet side. (DG) [de

  13. PWSCC of steam generator divider plates in alloy 600: coupling field characterizations with R-D studies

    International Nuclear Information System (INIS)

    Couvant, T.; Vaillant, F.; Miloudi, S.; Deforge, D.; Thebault, Y.

    2011-01-01

    Some IGSCC (Intergranular Stress Corrosion Cracks) indications have been observed at the cold work surface of the hot side (325 C) of some divider plates of steam generators (SG) since 2002. Based on many in-service inspection campaigns (about 100 SG inspections), no evidence of propagation following the first detection has never been observed. In this context, crack propagation tests were carried out in EDF in order to evaluate the susceptibility to SCC of warm rolled plates made of Alloy 600 as a function of the degree of cold work. Some results recently obtained in the EDF Hot Laboratories on the decommissioned SG1 of Chinon B1 were coupled with calibrated crack propagation laws on cold worked materials. Results enlightened the restricted susceptibility to observe a significant crack depth over the steam generator lifetime. Along the most probable crack growth path, the maximal crack growth rate (CGR) was lower than 300 μm.cycle -1 and the CGR did not exceed 260 μm.cycle -1 as soon as the local plastic deformation was lower than 0.07. A laboratory SCC test on a specimen with a superficial cold worked layer confirmed the good resistance to SCC when the local plastic strain was lower than 0.07, in good agreement with the field experience. (authors)

  14. [Isolation of a methanol-utilizing strain and its application for determining methanol].

    Science.gov (United States)

    Guo, Jun; Gao, Wei; Zhang, Qiang; Qu, Fei; Lu, Dongtao; Zheng, Jun; Pang, Jinmei; Yang, Yujing

    2013-08-04

    To isolate and characterize bacteria that can be used todevelop microbial biosensor for methanol (MeOH) determination. We used selective medium and streak plate to isolate bacteria. Morphological, physiological characteristics and 16S rDNA sequence analysis were used to identify the strain. An MeOH biosensor was then developed by immobilizing M211 along with dissolved oxygen (O2) sensor. An MeOH utilizing bacterium was isolated from biogas-producing tank using methanol as the sole carbon source, and identified as Methylobacteriumorganophilium. Decrease of O2 concentration is linearly related to the MeOH concentration in the range from 0.02% to 1%, with the MeOH detection limit of 0.27 mg/L. The response time of the biosensor is within 20 min. Furthermore, the result of interference test and the detection of methanol sample are both satisfactory. Good results are obtained in interference test and the detection of methanol sample. The proposed method seems very attractive in monitoring methanol.

  15. Process assessment of small scale low temperature methanol synthesis

    International Nuclear Information System (INIS)

    Hendriyana; Susanto, Herri; Subagjo

    2015-01-01

    Biomass is a renewable energy resource and has the potential to make a significant impact on domestic fuel supplies. Biomass can be converted to fuel like methanol via several step process. The process can be split into following main steps: biomass preparation, gasification, gas cooling and cleaning, gas shift and methanol synthesis. Untill now these configuration still has a problem like high production cost, catalyst deactivation, economy of scale and a huge energy requirements. These problems become the leading inhibition for biomass conversion to methanol, which should be resolved to move towards the economical. To address these issues, we developed various process and new configurations for methanol synthesis via methyl formate. This configuration combining two reactors: the one reactor for the carbonylation of methanol and CO to form methyl formate, and the second for the hydrogenolysis of methyl formate and H 2 to form two molecule of methanol. Four plant process configurations were compared with the biomass basis is 300 ton/day. The first configuration (A) is equipped with a steam reforming process for converting methane to CO and H 2 for increasing H 2 /CO ratio. CO 2 removal is necessary to avoid poisoning the catalyst. COSORB process used for the purpose of increasing the partial pressure of CO in the feed gas. The steam reforming process in B configuration is not used with the aim of reducing the number of process equipment, so expect lower investment costs. For C configuration, the steam reforming process and COSORB are not used with the aim of reducing the number of process equipment, so expect lower investment costs. D configuration is almost similar to the configuration A. This configuration difference is in the synthesis of methanol which was held in a single reactor. Carbonylation and hydrogenolysis reactions carried out in the same reactor one. These processes were analyzed in term of technical process, material and energy balance and economic

  16. Process assessment of small scale low temperature methanol synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hendriyana [Chemical Engineering Department, Faculty of Engineering, Jenderal Achmad Yani Univerity (Indonesia); Chemical Engineering Department, Faculty of Industrial Technology, InstitutTeknologi Bandung (Indonesia); Susanto, Herri, E-mail: herri@che.itb.ac.id; Subagjo [Chemical Engineering Department, Faculty of Industrial Technology, InstitutTeknologi Bandung (Indonesia)

    2015-12-29

    Biomass is a renewable energy resource and has the potential to make a significant impact on domestic fuel supplies. Biomass can be converted to fuel like methanol via several step process. The process can be split into following main steps: biomass preparation, gasification, gas cooling and cleaning, gas shift and methanol synthesis. Untill now these configuration still has a problem like high production cost, catalyst deactivation, economy of scale and a huge energy requirements. These problems become the leading inhibition for biomass conversion to methanol, which should be resolved to move towards the economical. To address these issues, we developed various process and new configurations for methanol synthesis via methyl formate. This configuration combining two reactors: the one reactor for the carbonylation of methanol and CO to form methyl formate, and the second for the hydrogenolysis of methyl formate and H{sub 2} to form two molecule of methanol. Four plant process configurations were compared with the biomass basis is 300 ton/day. The first configuration (A) is equipped with a steam reforming process for converting methane to CO and H{sub 2} for increasing H{sub 2}/CO ratio. CO{sub 2} removal is necessary to avoid poisoning the catalyst. COSORB process used for the purpose of increasing the partial pressure of CO in the feed gas. The steam reforming process in B configuration is not used with the aim of reducing the number of process equipment, so expect lower investment costs. For C configuration, the steam reforming process and COSORB are not used with the aim of reducing the number of process equipment, so expect lower investment costs. D configuration is almost similar to the configuration A. This configuration difference is in the synthesis of methanol which was held in a single reactor. Carbonylation and hydrogenolysis reactions carried out in the same reactor one. These processes were analyzed in term of technical process, material and energy

  17. Activity Tests of Macro-Meso Porous Catalysts over Metal Foam Plate for Steam Reforming of Bio-Ethanol.

    Science.gov (United States)

    Park, No-Kuk; Jeong, Yong Han; Kang, Misook; Lee, Tae Jin

    2018-09-01

    The catalytic activity of a macro-mesoporous catalyst coated on a metal foam plate in the reforming of bio-ethanol to synthesis gas was investigated. The catalysts were prepared by coating a support with a noble metal and transition metal. The catalytic activity for the production of synthetic gas by the reforming of bio-ethanol was compared according to the support material, reaction temperature, and steam/carbon ratio. The catalysts coated on the metal foams were prepared using a template method, in which macro-pores and meso-pores were formed by mixing polymer beads. In particular, the thermodynamic equilibrium composition of bio-ethanol reforming with the reaction temperature and steam/carbon ratio to produce synthetic gas was examined using the HSC (Enthalpy-Entropy-Heat capacity) chemistry program in this study. The composition of hydrogen and carbon monoxide in the reformate gas produced by steam reforming over the Rh/Ni-Ce-Zr/Al2O3-based pellet type catalysts and metal foam catalysts that had been coated with the Rh/Al-Ce-Zr-based catalysts was investigated by experimental activity tests. The activity of the metal foam catalyst was higher than that of the pellet type catalyst.

  18. Parametric study on density stratification erosion caused by a horizontal steam jet interacting with a vertical plate obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Paranjape, S., E-mail: Sidharth.paranjape@psi.ch; Kapulla, R., E-mail: ralf.kapulla@psi.ch; Mignot, G., E-mail: guillaume.mignot@psi.ch; Paladino, D., E-mail: domenico.paladino@psi.ch

    2017-02-15

    Highlights: • Helium layer breakup by horizontal steam jet impinging on vertical plate. • A small change in geometric configuration lead to a large change in flow pattern. • The functional dependence of erosion front motion on time. • Creation of a concentration stratification in adjacent vessel. - Abstract: During postulated severe accident scenarios in nuclear power plants, a hydrogen-rich layer might form at the top of the reactor containment. Various flow patterns resulting from the release of steam from the primary circuit might break the layer and redistribute hydrogen in the containment. The prediction of the gas transport during the accident requires detailed modeling of the processes involved. Advanced lumped parameter codes or computational fluid dynamics codes are used for this purpose. These codes need to be validated against experimental data obtained in large scale experimental facilities, where scale distortions are reduced. In order to obtain the required data with high spatial and temporal resolution, experiments were carried out in the PANDA facility in Switzerland as a part of OECD/HYMERES (HYdrogen Mitigation Experiments for Reactor Safety) project. The present experiments address the breakup of a layer rich in helium (used as simulant for hydrogen), under steam environment and its redistribution in two interconnected vessels (total volume of 183.3 m{sup 3}) under the action of a diffused flow resulting from the interaction of a horizontal steam jet with a vertical plate obstruction. The influence of the distance between the jet exit and the obstruction on the flow pattern was investigated. Spatial and temporal distribution of the gas concentration, the temperature and local gas velocity field were measured. It was found that a small change in the geometric configuration lead to a large change in the flow pattern. Reducing the jet-obstruction distance slowed down the helium-layer erosion process by a factor of two. Additionally, the

  19. Compact methanol reformer test for fuel-cell powered light-duty vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Emonts, B; Hoehlein, B; Peters, R [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energieverfahrenstechnik (IEV); Hansen, J B; Joergensen, S L [Haldor Topsoe A/S, Lyngby (Denmark)

    1998-03-15

    On-board production of hydrogen from methanol based on a steam reformer in connection with the use of low-temperature fuel-cells (PEMFC) is an attractive option as energy conversion unit for light-duty vehicles. A steam reforming process at higher pressures with an external burner offers advantages in comparison to a steam reformer with integrated partial oxidation in terms of total efficiency for electricity production. The main aim of a common project carried out by the Forschungszentrum Juelich (FZJ), Haldor Topsoee A/S (HTAS) and Siemens AG is to design, to construct and to test a steam reformer reactor concept (HTAS) with external catalytic burner (FZJ) as heat source as well as catalysts for heterogeneously catalyzed hydrogen production (HTAS), concepts for gas treatment (HTAS, FZJ) and a low-temperature fuel cell (Siemens). Based on the experimental results obtained so far concerning methanol reformers, catalytic burners and gas conditioning units, our report describes the total system, a test unit and preliminary test results related to a hydrogen production capacity of 50 kW (LHV) and dynamic operating conditions. This hydrogen production system is aimed at reducing the specific weight (<2 kg/kW{sub th} or 4 kg/kW{sub el}) combined with high efficiency for net electricity generation from methanol (about 50%) and low specific emissions. The application of Pd-membranes as gas cleaning unit fulfill the requirements with high hydrogen permeability and low cost of the noble metal. (orig.)

  20. Nuclear reactor steam depressurization valve

    International Nuclear Information System (INIS)

    Moore, G.L.

    1991-01-01

    This patent describes improvement in a nuclear reactor plant, an improved steam depressurization valve positioned intermediate along a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe. The improvement comprises: a housing including a domed cover forming a chamber and having a partition plate dividing the chamber into a fluid pressure activation compartment and a steam flow control compartment, the valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with a source of fluid pressure for operating the valve; a valve set mounted within the fluid flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining the connection and having a radially projecting flange at the other end with a contoured extended valve sealing flange provided with an annular valve sealing member, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in the partition plate with one terminal and extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, the valve cylinder being surrounded by two bellow fluid seals and provided with guides to inhibit lateral movement, an end of the valve cylinder extending into the fluid flow control compartment having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening fluid flow through the valve

  1. Steam explosion treatment for ethanol production from branches pruned from pear trees by simultaneous saccharification and fermentation.

    Science.gov (United States)

    Sasaki, Chizuru; Okumura, Ryosuke; Asada, Chikako; Nakamura, Yoshitoshi

    2014-01-01

    This study investigated the production of ethanol from unutilized branches pruned from pear trees by steam explosion pretreatment. Steam pressures of 25, 35, and 45 atm were applied for 5 min, followed by enzymatic saccharification of the extracted residues with cellulase (Cellic CTec2). High glucose recoveries, of 93.3, 99.7, and 87.1%, of the total sugar derived from the cellulose were obtained from water- and methanol-extracted residues after steam explosion at 25, 35, and 45 tm, respectively. These values corresponded to 34.9, 34.3, and 27.1 g of glucose per 100 g of dry steam-exploded branches. Simultaneous saccharification and fermentation experiments were done on water-extracted residues and water- and methanol-extracted residues by Kluyveromyces marxianus NBRC 1777. An overall highest theoretical ethanol yield of 76% of the total sugar derived from cellulose was achieved when 100 g/L of water- and methanol-washed residues from 35 atm-exploded pear branches was used as substrate.

  2. Calculation of relative tube/tube support plate displacements in steam generators under accident condition loads using non-linear dynamic analysis methodologies

    International Nuclear Information System (INIS)

    Smith, R.E.; Waisman, R.; Hu, M.H.; Frick, T.M.

    1995-01-01

    A non-linear analysis has been performed to determine relative motions between tubes and tube support plates (TSP) during a steam line break (SLB) event for steam generators. The SLB event results in blowdown of steam and water out of the steam generator. The fluid blowdown generates pressure drops across the TSPS, resulting in out-of-plane motion. The SLB induced pressure loads are calculated with a computer program that uses a drift-flux modeling of the two-phase flow. In order to determine the relative tube/TSP motions, a nonlinear dynamic time-history analysis is performed using a structural model that considers all of the significant component members relative to the tube support system. The dynamic response of the structure to the pressure loads is calculated using a special purpose computer program. This program links the various substructures at common degrees of freedom into a combined mass and stiffness matrix. The program accounts for structural non-linearities, including potential tube and TSP interaction at any given tube position. The program also accounts for structural damping as part of the dynamic response. Incorporating all of the above effects, the equations of motion are solved to give TSP displacements at the reduced set of DOF. Using the displacement results from the dynamic analysis, plate stresses are then calculated using the detailed component models. Displacements form the dynamic analysis are imposed as boundary conditions at the DOF locations, and the finite element program then solves for the overall distorted geometry. Calculations are also performed to assure that assumptions regarding elastic response of the various structural members and support points are valid

  3. Design and manufacture of steam generators for replacement

    International Nuclear Information System (INIS)

    Hirano, Hiroshi; Kuri, Syuhei

    1995-01-01

    The basic specification of the steam generators for replacement as heat exchangers (the pressure, temperature, flow rate and thermal output on primary and secondary sides) is set same as that of steam generators before replacement, but the latest design reflecting the operation experience obtained so far and taking the countermeasures for preventing heating tube damage in it is adopted, such as the heating tubes made of TT 690 alloy, the tube support plates with four-lobe shape tube holes made of stainless steel, the stainless steel rest fittings of three in one set and so on. After the heating tube break accident in Mihama No. 2 plant, the quality control was further strengthened. The comparison of the specifications of the steam generators of respective plants before and after the replacement is shown. The main objective of improving steam generators is the heightening of the reliability of heating tubes against intergranular attack and primary water stress corrosion cracking. The improvements of heating tube material, tube support plate material, secondary side heat flow, the shape of tube holes of tube support plates, the method of expanding heating tubes, and vibration-controlling fittings are explained. As to the manufacturing procedure and quality control, the manufacture of raw materials, the build-up welding of tube plates, the manufacture of lower half shell plates, the tube hole making of support plates, the insection of outer cylinder, flow rate distribution plate. Support plates and heating tubes, the sealing welding and expanding of heating tubes, the fixing of rest fittings, the manufacture and fixing of water chamber cover, the manufacture of upper half shell, the fixing of parts inside it, the final joint and inspection are described. (K.I.)

  4. Effects of non-condensable gas on the condensation of steam

    International Nuclear Information System (INIS)

    Jackson, J.D.; An, P.; Reinert, A.; Ahmadinejad, M.

    2000-01-01

    The experimental work reported here was undertaken with the aim of extending the database currently available on the condensation of steam in the presence of non-condensable gases and thereby improving the empirical input to thermal-hydraulic codes which might be used for design and safety assessment of advanced water-cooled nuclear reactors. Heat was removed from flowing mixtures of steam and air in a test section by means of a water-cooled condensing plate. The test facility constructed for the study incorporates a degassing unit which supplies water to a boiler. This delivers steam steadily to a mixing chamber where it joins with a flow of preheated air. The mixture of steam and air is supplied to the bottom of a cylindrical test section in which it flows upwards over a double sided condensing plate which can be vertical, inclined or horizontal, The rate at which heat is removed by cooling water flowing through internal passages in the plate can de determined calorimetrically knowing the flow rate of the water and its temperature rise. After commissioning experiments had shown that reliable measurements of condensation heat transfer rate could be made using the test facility, a programme of development work followed in the course of which three different designs of condensing plate were evaluated in turn. The version eventually used in the main programme of experiments which followed was made from copper. However, its surfaces were coated with a thin layer of nickel and then with one of chromium. It was found that such a surface consistently promoted dropwise condensation and showed no signs of deterioration after lengthy periods of use. The rate of heat removal from pure steam and from mixtures of steam and air in varying proportions was measured as a function of plate sub-cooling for a variety of plate orientations. (author)

  5. Primary manway shielding and exhaust covers for a steam generator

    International Nuclear Information System (INIS)

    Wallace, W.R.; Immel, A.K.; Boro, I.; Lester, W.E. II.

    1990-01-01

    This paper discusses a radiation emission shielding cover in combination with a steam generator of a nuclear reactor for covering at least a portion of a manway of the steam generator for protecting an operator from radiation emission. It comprises a plate; a mounting assembly including a mounting flange for securing the mounting assembly adjacent the manway of the steam generator and a mounting bracket; a slide means mounted on the mounting bracket adjacent the manway; and guide means mounted on the plate for receiving the slide means such that the plate can be moved from an open position adjacent the manway to a closed position over at least a portion of the manway

  6. Steam exit flow design for aft cavities of an airfoil

    Science.gov (United States)

    Storey, James Michael; Tesh, Stephen William

    2002-01-01

    Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

  7. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  8. Methanol steam reforming over Pd/ZnO and Pd/CeO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, Easwar S.; Bej, Shyamal K.; Thompson, Levi T. [University of Michigan, Department of Chemical Engineering, 3026 H.H. Dow Building, 2300 Hayward Avenue, Ann Arbor, MI 48109-2136 (United States)

    2005-08-10

    The goal of work described in this paper was to better understand the methanol steam reforming (MSR) activity and selectivity patterns of ZnO and CeO{sub 2} supported Pd catalysts. This reaction is being used to produce H{sub 2}-rich gas for a number of applications including hydrogen fuel cells. The Pd/ZnO catalysts had lower MSR rates but were more selective for the production of CO{sub 2} than the Pd/CeO{sub 2} catalysts. The CH{sub 3}OH conversion rates were proportional to the H{sub 2} chemisorption uptake suggesting that the rate determining step was catalyzed by Pd. The corresponding turnover frequencies averaged 0.8+/-0.3s{sup -1} and 0.4+/-0.2s{sup -1} at 230{sup o}C for the Pd/ZnO and Pd/CeO{sub 2} catalysts, respectively. The selectivities are explained based on the reaction pathways, and characteristics of the support. The key surface intermediate appeared to be a formate. The ZnO supported catalysts had a higher density of acidic sites and favored pathways where the intermediate was converted to CO{sub 2} while the CeO{sub 2} supported catalysts had a higher density of basic sites and favored the production of CO.

  9. The role of various fuels on microwave-enhanced combustion synthesis of CuO/ZnO/Al2O3 nanocatalyst used in hydrogen production via methanol steam reforming

    International Nuclear Information System (INIS)

    Ajamein, Hossein; Haghighi, Mohammad; Alaei, Shervin

    2017-01-01

    Graphical abstract: CuO/ZnO/Al 2 O 3 nanocatalysts were synthesized by the fast and simple microwave enhanced combustion method. Considering that the fuel type is one of the effective parameters on quality of the prepared nanocatalysts, different fuels such as sorbitol, propylene glycol, glycerol, diethylene glycol and ethylene glycol were used. XRD, FESEM, FTIR, EDX, and BET analyses were applied to determine the physicochemical properties of fabricated nanocatalysts. The catalytic experiments were performed in a fixed bed reactor in the temperature range of 160–300 °C. The characteristic and reactivity properties of fabricated nanocatalysts proved that ethylene glycol is the suitable fuel for preparation of CuO/ZnO/Al 2 O 3 nanocatalysts via microwave enhanced combustion method. - Highlights: • Microwave combustion synthesis of CuO/ZnO/Al 2 O 3 nanocatalysts by different fuels. • Enhancement of methanol conversion at low temperatures by selecting proper fuel. • Providing a large number of combustion pores by application of ethylene glycol as fuel. • Increase of CO selectivity in steam methanol reforming by Zn(0 0 2) crystallite facet. - Abstract: A series of CuO/ZnO/Al 2 O 3 nanocatalysts were synthesized by the microwave enhanced combustion method to evaluate the influence of fuel type. Sorbitol, propylene glycol, glycerol, diethylene glycol and ethylene glycol were used as fuel. XRD results revealed that application of ethylene glycol led to highly dispersed CuO and ZnO crystals. It was more highlighted about Cu(1 1 1) crystallite facet which known as the main active site of methanol steam reforming. Moreover, using ethylene glycol resulted homogeneous morphology and narrow particles size distribution (average surface particle size is about 265 nm). Due to the significant physicochemical properties, the catalytic experiments showed that the sample prepared by ethylene glycol achieved total conversion of methanol at 260 °C. Its carbon monoxide

  10. Diagnostic system of steam generator, especially molten metal heated steam generator

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1986-01-01

    A diagnostic system is described and graphically represented consisting of a leak detector, a medium analyzer and sensors placed on the piping connected to the indication sections of both tube plates. The advantage of the designed system consists in the possibility of detecting tube failure immediately on leak formation, especially in generators with duplex tubes. This shortens the period of steam generator shutdown for repair and reduces power losses. The design also allows to make periodical leak tests during planned steam generator shutdowns. (A.K.)

  11. 49 CFR 230.106 - Steam locomotive frame.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive frame. 230.106 Section 230.106... Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance and inspection. Frames, decks, plates, tailpieces, pedestals, and braces shall be maintained in a safe and...

  12. Process of corrosion protection for a steam generator tube and device to apply it

    International Nuclear Information System (INIS)

    Malagola, P.; Vassal, J.M.

    1985-01-01

    The steam generator tube is fixed by crimping in a tube plate; a metallic layer compatible with the tube material is electrodeposited on the inner side of the tube after its mounting in the tube plate, on both side of the plate face in contact with the water to be steamed, along a length approximately longer than the transition zone between the crimped part of the tube and the part which is not crimped. The external side of the tube can be also covered by a metallic layer before its mounting through the tube plate. The metallic layer can be nickel. The invention applies, more particularly, to PWR steam generators [fr

  13. Lightweight Stacks of Direct Methanol Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Valdez, Thomas

    2004-01-01

    An improved design concept for direct methanol fuel cells makes it possible to construct fuel-cell stacks that can weigh as little as one-third as much as do conventional bipolar fuel-cell stacks of equal power. The structural-support components of the improved cells and stacks can be made of relatively inexpensive plastics. Moreover, in comparison with conventional bipolar fuel-cell stacks, the improved fuel-cell stacks can be assembled, disassembled, and diagnosed for malfunctions more easily. These improvements are expected to bring portable direct methanol fuel cells and stacks closer to commercialization. In a conventional bipolar fuel-cell stack, the cells are interspersed with bipolar plates (also called biplates), which are structural components that serve to interconnect the cells and distribute the reactants (methanol and air). The cells and biplates are sandwiched between metal end plates. Usually, the stack is held together under pressure by tie rods that clamp the end plates. The bipolar stack configuration offers the advantage of very low internal electrical resistance. However, when the power output of a stack is only a few watts, the very low internal resistance of a bipolar stack is not absolutely necessary for keeping the internal power loss acceptably low.

  14. Bridging the Gap: From Model Surfaces to Nanoparticle Analogs for Selective Oxidation and Steam Reforming of Methanol and Selective Hydrogenation Catalysis

    Science.gov (United States)

    Boucher, Matthew B.

    Most industrial catalysts are very complex, comprising of non-uniform materials with varying structures, impurities, and interaction between the active metal and supporting substrate. A large portion of the ongoing research in heterogeneous catalysis focuses on understanding structure-function relationships in catalytic materials. In parallel, there is a large area of surface science research focused on studying model catalytic systems for which structural parameters can be tuned and measured with high precision. It is commonly argued, however, that these systems are oversimplified, and that observations made in model systems do not translate to robust catalysts operating in practical environments; this discontinuity is often referred to as a "gap." The focus of this thesis is to explore the mutual benefits of surface science and catalysis, or "bridge the gap," by studying two catalytic systems in both ultra-high vacuum (UHV) and near ambient-environments. The first reaction is the catalytic steam reforming of methanol (SRM) to hydrogen and carbon dioxide. The SRM reaction is a promising route for on-demand hydrogen production. For this catalytic system, the central hypothesis in this thesis is that a balance between redox capability and weak binding of reaction intermediates is necessary for high SRM activity and selectivity to carbon dioxide. As such, a new catalyst for the SRM reaction is developed which incorporates very small amounts of gold (liquid-phase, stirred-tank batch reactor under a hydrogen head pressure of approximately 7 bar. Palladium alloyed into the surface of otherwise inactive copper nanoparticles shows a marked improvement in selectivity when compared to monometallic palladium catalysts with the same metal loading. This effect is attributed hydrogen spillover onto the copper surface. In summary, the development of new, highly active and selective catalysts for the methanol steam reforming reaction and for the partial hydrogenation of alkynes

  15. Modeling and simulation of a packed bed reactor for hydrogen by methanol steam reforming

    International Nuclear Information System (INIS)

    Aboudheir, A.; Idem, R.

    2004-01-01

    'Full text:' The performance of a catalytic packed bed tubular reactor for hydrogen production depends on mass transport characteristics and temperature distribution in the reactor. To accurately predict this performance, a rigorous numerical model has been developed based on coupled mass, energy, and momentum balance equations in cylindrical coordinates. This comprehensive model takes into account the variations of the concentration and temperature in both the axial and radial directions as well as the pressure drop along the packed reactor. Also, experimental measurements for hydrogen production were collected using a manganese-promoted co-precipitated Cu-Al catalyst for methanol-steam reforming in a micro-reactor having 10 mm i.d. and 460 mm overall length. The operating temperature ranged from 443 to 523 K and the space-time ranged from 0.1 to 2.5 kg cat h/kmol CH3OH. The simulation results were found to be in close agreement with the experimental data over the various operating conditions. This confirms the validity of both the numerical model of this work and our previous published kinetics models for this reaction system. In addition, the model formulation is applicable to handle reactions, not only for the microreactor presented in this work, but also, for other laboratory size and industrial scale processes for hydrogen production by hydrocarbon reformation. (author)

  16. Experience with modular steam generator production and application of new testing methods

    International Nuclear Information System (INIS)

    Olesovsky

    Experience is reviewed gained at the Trebic IBZKG plant with the production of modular steam generators. The plant started producing steam generators for the Jaslovske Bohunice nuclear power plant in 1965. In addition to the steam generator for the A-1, the plant also produced a loop for the Melekess power plant and a steam generator for the BOR-60 reactor. Operating experience gained so far allowed improving the quality of the BOR steam generator, especially in the tube-tube plate joint. A double tube plate was used and the welded joint shape was changed. As a result of high requirements on the quality of welded joints, the steam generator has successfully been in operation for more then 10,000 hours. The existing experience was utilized in designing a new steam generator named Nadya. Many design and technological requirements were presented concerning the Nadya generator and many new checking operations have been included in technology. (Kr)

  17. A method of multi-crack shape identification from eddy current testing signals of steam generator tubes including support plates as noise sources

    International Nuclear Information System (INIS)

    Nagaya, Yoshiaki; Endo, Hisashi; Takagi, Toshiyuki; Uchimoto, Tetsuya

    2005-01-01

    This paper deals with identifying multiple cracks from eddy current testing (ECT) signals obtained in a steam generator tube with a support plate and deposits. Assume two-dimensionally scanned ECT signals to be a picture image, then the signal processing by a multi-frequency technique eliminates noise caused by the support plate and deposits. A template matching with help of genetic algorithms detects number and positions of cracks from the image after the signal processing. Inverse analysis estimates the crack profile based on the predicted position of cracks. The number and positions of the cracks are sufficiently well predicted. Crack shape reconstructions are achieved with a satisfactory degree of accuracy. (author)

  18. Improved Direct Methanol Fuel Cell Stack

    Science.gov (United States)

    Wilson, Mahlon S.; Ramsey, John C.

    2005-03-08

    A stack of direct methanol fuel cells exhibiting a circular footprint. A cathode and anode manifold, tie-bolt penetrations and tie-bolts are located within the circular footprint. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet and outlet cathode manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold, where the serpentine channels of the anode are orthogonal to the serpentine channels of the cathode. Located between the two plates is the fuel cell active region.

  19. Investigation of a methanol reformer concept considering the particular impact of dynamics and long-term stability for use in a fuel-cell-powered passenger car

    Science.gov (United States)

    Peters, R.; Düsterwald, H. G.; Höhlein, B.

    A methanol reformer concept including a reformer, a catalytic burner, a gas cleaning unit, a PEMFC and an electric motor for use in fuel-cell-powered passenger cars was investigated. Special emphasis was placed on the dynamics and the long-term stability of the reformer. Experiments on a laboratory scale were performed in a methanol steam reformer consisting of four different reactor tubes, which were separately balanced. Due to the endothermy of the steam reforming reaction of methanol, a sharp drop in the reaction temperature of about 50 K occurs at the beginning of the catalyst bed. This agrees well with the high catalytic activity at the entrance of the catalyst bed. Forty-five percent of the methanol was converted within the first 10 cm of the catalyst bed where 12.6 g of the CuO/ZnO catalyst was located. Furthermore, CO formation during methanol steam reforming strongly depends on methanol conversion. Long-term measurements for more than 700 h show that the active reaction zone moved through the catalyst bed. Calculations, on the basis of these experiments, revealed that 63 g of reforming catalyst was necessary for mobile PEMFC applications, in this case for 400 W el at a system efficiency of 42% and a theoretical specific hydrogen production of 5.2 m 3n/(h kg Cat). This amount of catalyst was assumed to maintain a hydrogen production of at least 80% of the original amount over an operating range of 3864 h. Cycled start-up and shut-down processes of the methanol steam reformer under nitrogen and hydrogen atmospheres did not harm the catalytic activity. The simulation of the breakdown of the heating system, in which a liquid water/methanol mixture was in close contact with the catalyst, did not reveal any deactivation of the catalytic activity.

  20. Catalytic production of hydrogen from methanol for mobile, stationary and portable fuel-cell power plants

    International Nuclear Information System (INIS)

    Lukyanov, Boris N

    2008-01-01

    Main catalytic processes for hydrogen production from methanol are considered. Various schemes of fuel processors for hydrogen production in stationary, mobile and portable power plants based on fuel cells are analysed. The attention is focussed on the design of catalytic reactors of fuel processors and on the state-of-the-art in the design of catalysts for methanol conversion, carbon monoxide steam conversion and carbon monoxide selective oxidation. Prospects for the use of methanol in on-board fuel processors are discussed.

  1. PWR steam generator chemical cleaning. Phase II. Final report

    International Nuclear Information System (INIS)

    1980-01-01

    Two techniques believed capable of chemically dissolving the corrosion products in the annuli between tubes and support plates were developed in laboratory work in Phase I of this project and were pilot tested in Indian Point Unit No. 1 steam generators. In Phase II, one of the techniques was shown to be inadequate on an actual sample taken from an Indian Point Unit No. 2 steam generator. The other technique was modified slightly, and it was demonstrated that the tube/support plate annulus could be chemically cleaned effectively

  2. Hynol: An economic process for methanol production from biomass and natural gas with reduced CO2 emission

    Science.gov (United States)

    Steinberg, M.; Dong, Yuanji

    1993-10-01

    The Hynol process is proposed to meet the demand for an economical process for methanol production with reduced CO2 emission. This new process consists of three reaction steps: (1) hydrogasification of biomass, (2) steam reforming of the produced gas with additional natural gas feedstock, and (3) methanol synthesis of the hydrogen and carbon monoxide produced during the previous two steps. The H2-rich gas remaining after methanol synthesis is recycled to gasify the biomass in an energy neutral reactor so that there is no need for an expensive oxygen plant as required by commercial steam gasifiers. Recycling gas allows the methanol synthesis reactor to perform at a relatively lower pressure than conventional while the plant still maintains high methanol yield. Energy recovery designed into the process minimizes heat loss and increases the process thermal efficiency. If the Hynol methanol is used as an alternative and more efficient automotive fuel, an overall 41% reduction in CO2 emission can be achieved compared to the use of conventional gasoline fuel. A preliminary economic estimate shows that the total capital investment for a Hynol plant is 40% lower than that for a conventional biomass gasification plant. The methanol production cost is $0.43/gal for a 1085 million gal/yr Hynol plant which is competitive with current U.S. methanol and equivalent gasoline prices. Process flowsheet and simulation data using biomass and natural gas as cofeedstocks are presented. The Hynol process can convert any condensed carbonaceous material, especially municipal solid waste (MSW), to produce methanol.

  3. Analysis of steam explosions in plate-type, uranium-aluminum fuel test reactors

    International Nuclear Information System (INIS)

    Taleyarkhan, R.P.

    1989-01-01

    The concern over steam explosions in nuclear reactors can be traced to prompt critical nuclear excursions in aluminum-clad/fueled test reactors, as well as to explosive events in aluminum, pulp, and paper industries. The Reactor Safety Study prompted an extensive analytical and experimental effort for over a decade. This has led to significant improvements in their understanding of the steam explosion issue for commercial light water reactors. However, little progress has been made toward applying the lessons learned from this effort to the understanding and modeling of steam explosion phenomena in aluminum-clad/fueled research and test reactors. The purposes of this paper are to (a) provide a preliminary analysis of the destructive events in test reactors, based on current understandings of steam explosions; (b) provide a proposed approach for determining the likelihood of a steam explosion event under scenarios in which molten U-Al fuel drops into a water-filled cavity; and (c) present a benchmarking study conducted to estimate peak pressure pulse magnitudes

  4. Free vibration analysis of a steam generator tube bundle with and without lateral support

    International Nuclear Information System (INIS)

    King, D.M.

    1979-04-01

    The vibrational modes and frequency characteristics of a pressurized water reactor (PWR) steam generator tube bundle assembly with and without lateral support in a fluid environment are analyzed. The idealized half-model was constructed using the SAP-IV finite element code. Free vibration analyses were performed for an in-air case and a submerged in-water case, each with different constraint conditions at steam generator tube bundle assembly support plates 10 and 11. These constraint conditions included having both support plates free, having both support plates fixed, and having support plate 11 free while support plate 10 was fixed. It was found that as the support plate constraints were removed, the frequency range for each case increased significantly

  5. PWR steam generator chemical cleaning. Phase I: solvent and process development. Volume II

    International Nuclear Information System (INIS)

    Larrick, A.P.; Paasch, R.A.; Hall, T.M.; Schneidmiller, D.

    1979-01-01

    A program to demonstrate chemical cleaning methods for removing magnetite corrosion products from the annuli between steam generator tubes and the tube support plates in vertical U-tube steam generators is described. These corrosion products have caused steam generator tube ''denting'' and in some cases have caused tube failures and support plate cracking in several PWR generating plants. Laboratory studies were performed to develop a chemical cleaning solvent and application process for demonstration cleaning of the Indian Point Unit 2 steam generators. The chemical cleaning solvent and application process were successfully pilot-tested by cleaning the secondary side of one of the Indian Point Unit 1 steam generators. Although the Indian Point Unit 1 steam generators do not have a tube denting problem, the pilot test provided for testing of the solvent and process using much of the same equipment and facilities that would be used for the Indian Point Unit 2 demonstration cleaning. The chemical solvent selected for the pilot test was an inhibited 3% citric acid-3% ascorbic acid solution. The application process, injection into the steam generator through the boiler blowdown system and agitation by nitrogen sparging, was tested in a nuclear environment and with corrosion products formed during years of steam generator operation at power. The test demonstrated that the magnetite corrosion products in simulated tube-to-tube support plate annuli can be removed by chemical cleaning; that corrosion resulting from the cleaning is not excessive; and that steam generator cleaning can be accomplished with acceptable levels of radiation exposure to personnel

  6. PWR steam generator chemical cleaning. Phase I: Final report, Volume I

    International Nuclear Information System (INIS)

    1978-07-01

    Two chemical cleaning solvent systems and two application methods were developed to remove the sludge in nuclear steam generators and to remove the corrosion products in the annuli between the steam generator tubes and the support plates. Laboratory testing plus subsequent pilot testing has demonstrated that, in a reasonable length of time, both solvents are capable of dissolving significant amounts of sludge, and of dissolving tightly packed magnetite in tube/support plate crevices. Further, tests have demonstrated that surface losses of the materials of construction in steam generators can be controlled to acceptable limits for the duration of the required cleaning period. Areas requiring further study and test have been identified, and a preliminary procedure for chemical cleaning nuclear steam generators has been chosen subject to quantification based on additional tests prior to actual in-plant demonstration

  7. Steam generator of the forced circulation type

    International Nuclear Information System (INIS)

    Forestier, Jean; Leblanc, Bernard; Monteil, Marcel; Monteil, Pierre

    1977-01-01

    The steam generator described is of the forced circulation single passage type comprising an outer casing including a vertical generally cylindrical side ring, an internal skirt coaxial with the outer casing, the bottom of this skirt having a free edge separated from a bottom end closing the outer casing, a central tube plate extending horizontally near a top end, in opposition to the bottom end, a peripheral tube plate, parallel to the central plate and located in the annular space under this central plate, a bundle of J shaped tubes [fr

  8. METHANE STEAM REACTION OVER NICKEL CATALYSTS IN THE HYNOL PROCESS

    Science.gov (United States)

    The report discusses the reaction of methane-steam over nickel catalysts in the Hynol process, a process that uses biomass and natural gas as feedstocks to maximize methanol yields and minimize greenhouse gas emissions. EPA's APPCD has established a laboratory in which to conduct...

  9. Unified modeling and feasibility study of novel green pathway of biomass to methanol/dimethylether

    International Nuclear Information System (INIS)

    Ravaghi-Ardebili, Zohreh; Manenti, Flavio

    2015-01-01

    Graphical abstract: Biomass-to-methanol/DME synthesis process layout. - Highlights: • Design, simulation, and control of the direct-storage concentrating solar plant. • Feasibility study of the low-temperature biomass gasification. • First-principles model of biomass gasifier. • First-principles model of one-step methanol/dimethylether synthesis reactor. • Integrated numerical platform for total plant simulation. - Abstract: A novel, integrated and unified process is proposed, modeled and studied for converting biomass to methanol (MeOH)/dimethylether (DME) to demonstrate its feasibility and applicability for the global industrial sector. The unified process consists of a concentrating solar power (CSP) plant, which supplies the produced steam to the biomass gasification process as well as to the downstream conversions to chemical commodities and energy carriers. To preserve the effectiveness of the biomass gasification with low-temperature solar-powered generated steam (approximately 400–410 °C), the gasification process is studied by means of a multi-complex (multi-scale, multi-phase, and multi-component) model and adapted to the novel proposed conditions. The syngas generated in the biomass gasification unit is then converted into MeOH/DME by means of one-step synthesis technology to improve the overall yield of the biomass-to-methanol process

  10. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant; Vanteru, Mahendra Reddy; Kumar, Sudarshan

    2015-01-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed

  11. Steam generator tube support plate degradation in French plants: maintenance strategy

    International Nuclear Information System (INIS)

    Gauchet, J.-P.; Gillet, N.; Stindel, M.

    1998-01-01

    This paper reports on the degradations of Steam Generator (SG) Tube Support Plates (TSPs) observed in French plants and the maintenance strategy adopted to continue operating the plant without any decrease of the required safety level. Only drilled carbon steel TSPs of early SGs are affected. Except the particular damage of the TSP8 of FESSENHEIM 2 caused by chemical cleaning procedures implemented in 1992, two main problems were observed almost exclusively on the upper TSP: Ligaments ruptured near the aseismic block located at 215 degrees. This degradation is perfectly detectable by bobbin coil inspection. It occurs very early in the life of the SG as can be seen from the records of previous inspections and no evolution of the signals was observed. This damage can be detected for 51M model SGs on several sites; Wastage of the ligaments resulting in enlargement of flow holes with in some cases complete consumption of a ligament. This damage was only observed for SGs of at GRAVELINES. This damage evolved cycle after cycle. Detailed studies were performed to analyze tubing behavior when a tube is not supported by the upper TSP because of missing ligaments. These studies evaluated the risk of vibratory instability, the behavior of both the TSP and the tubing in case of a seismic event or a LOCA and finally the behavior of the TSP in case of a Steam Line Break. Concerning vibratory instability it was possible to define zones where stability could not be demonstrated. Dampine, cables and sentinel plugs were then used when necessary to eliminate the risk of Steam Generator Tube Rupture (SGTR). For accidental conditions, it could be shown that no unacceptable damage occurs and that the core cooling function of the SG is always maintained if some tubes are plugged. From this analysis, It was possible to define the inspection programs for the different plants taking into account the specific situation of each plant regarding the damages detected. These programs include

  12. Visual inspection equipment for the secondary side of steam generators. Final report

    International Nuclear Information System (INIS)

    Hinton, M.S.; Chagnon, C.W.

    1981-05-01

    The development of miniature visual examination equipment capable of inspecting regions inside the tube bundles of nuclear steam generators to determine such factors as gap condition, tube outside surface condition, and material buildup is described. Tube-to-support plate interface regions at the tenth-support plate level in a once-through steam generator (Oconee 1) were visually examined. Other areas in the peripheral region were examined for conditions associated with available eddy-current and profilometer data

  13. General report of entrustment investigation for demonstration tests of turnover from oil to methanol in the thermal power plants in fiscal 1995. Total assessment of methanol using power generation technology; 1995 nendo sekiyu karyoku hatsudensho methanol tenkan nado jissho shiken itaku gyomu hokokusho sokatsu hokokusho. Methanol riyo hatsuden gijutsu sogo hyoka chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    To promote the introduction of methanol fuel into the thermal power plants, total assessment was provided. For calculating the methanol production cost, the plant was assumed to be constructed in the Southeast Asia or Middle East. Two methods, i.e., steam reforming and gaseous phase fluid methods, were investigated. Since the price of natural gas is low in the Middle East, the methanol production cost by the gaseous phase fluid method is estimated to be about 1.5 yen per thousand kcal. The transportation cost can be reduced into one-half to one-third of current cost using a large-scale tanker. Although the heating value of methanol per weight is lower than that of LNG, the volume flow of methanol is similar to that of LNG due to its low specific gravity. Conceptual designs were conducted for some power generation systems, such as gas turbine of combined cycle, diesel engine, and fuel cell. The power generation cost was estimated to be 8 to 9 yen per kWh, which depends on the receiving price of methanol. It is nearly equivalent to that of LNG combined cycle power generation. There are no problems of air pollution and ash disposal. When considering the long-term security of energy sources, the use of methanol would be one of the selections as utilization of natural gas. 6 refs., 33 figs., 25 tabs.

  14. Embalse steam generators - status in 2009

    International Nuclear Information System (INIS)

    Luna, P.; Yetisir, M.; Roy, S.; MacEacheron, R.

    2009-01-01

    The Embalse Nuclear Generating Station (ENGS) is a CANDU 6, a pressurized heavy water plant, with a net capacity of 648 MW. The primary heat transport system at Embalse includes four Steam Generators (SGs) manufactured by Babcock and Wilcox Canada (B and W). These steam generators are vertical recirculating heat exchangers with Incoloy 800 inverted U-tubes and an integral preheater. Embalse SGs performed very well until the late 1990s, when an increase in tube fretting was noticed in the U-bend region. In-service inspection in 2002 and 2004 confirmed that the cause of the tube fretting was flow accelerated corrosion (FAC) damage of scallop bar supports in the U-bend region. The straight leg tube support plates (TSPs) have also been degrading. Degradation was worst at the top support plates, and it was in the form of material loss on the cold leg. The hot leg TSPs were heavily fouled with deposits and flow areas were blocked. Visual inspections and subsequent studies showed that the cause of the TSP degradation was also FAC. The Embalse SGs have carbon steel supports that make them susceptible to FAC. To mitigate the effects of degraded tube support structures, three additional sets of anti-vibration bars were installed in the U-bend regions of all four steam generators in 2004. In 2007, an improved secondary-side chemistry specification was implemented to reduce the FAC rate and the hot leg TSPs was waterlanced. A root cause analysis and condition assessment was performed for the tube supports in 2007. Fitness for Service (FFS) evaluation was completed using the Canadian Industry Guidelines for steam generator tubes. The steam generators were returned to service and the plan has operated without another forced outage to date. The FAC degradation of the carbon steel U-bend tube support systems has had the most significant impact on the plant operation causing a number of forced outages. The discovery of the extent of TSP degradation and difficulties to repair TSPs

  15. Exergetic analysis and optimization of a solar-powered reformed methanol fuel cell micro-powerplant

    Science.gov (United States)

    Hotz, Nico; Zimmerman, Raúl; Weinmueller, Christian; Lee, Ming-Tsang; Grigoropoulos, Costas P.; Rosengarten, Gary; Poulikakos, Dimos

    The present study proposes a combination of solar-powered components (two heaters, an evaporator, and a steam reformer) with a proton exchange membrane fuel cell to form a powerplant that converts methanol to electricity. The solar radiation heats up the mass flows of methanol-water mixture and air and sustains the endothermic methanol steam reformer at a sufficient reaction temperature (typically between 220 and 300 °C). In order to compare the different types of energy (thermal, chemical, and electrical), an exergetic analysis is applied to the entire system, considering only the useful part of energy that can be converted to work. The effect of the solar radiation intensity and of different operational and geometrical parameters like the total inlet flow rate of methanol-water mixture, the size of the fuel cell, and the cell voltage on the performance of the entire system is investigated. The total exergetic efficiency comparing the electrical power output with the exergy input in form of chemical and solar exergy reaches values of up to 35%, while the exergetic efficiency only accounting for the conversion of chemical fuel to electricity (and neglecting the 'cost-free' solar input) is increased up to 59%. At the same time, an electrical power density per irradiated area of more than 920 W m -2 is obtained for a solar heat flux of 1000 W m -2.

  16. Apparatus for the separation of water from water-steam mixtures

    International Nuclear Information System (INIS)

    Judith, H.; Schwerdtner, O. von.

    1975-01-01

    Steam flowing from the high-pressure part of a saturated-steam turbine of nuclear power stations to the preheater or steam directly passing off to the low-pressure part contains a high amount of moisture. This is removed by a separating device in the overflow pipe working as an axial cyclon. To this end a twist generator with radially mounted guide vanes forces a twisting movement on the water-steam mixture whereby the water component is thrown towards the wall of the overflow pipe. Behind the twist generator the overflow pipe is provided with ring slots or annular gaps through which the centrifuged water gets into water collecting chambers concentrically surrounding the overflow pipe. The main water seperation results from the first annular gap through centrifugal effects. The rest is removed by steam suction through the other gaps. For steam suction purposes, i.e. in order to produce an underpressure, the collecting chambers of these gaps are connected with the overflow pipe behind the twist generators by means of a suction pipe. In order to also remove small water droplets without increasing the twist, an agglomerator is installed in the overflow pipe before the twist generator. It consists of baffle or guide plates within an elliptic intermediate piece in a bend of the overflow pipe. Therefore the flanks of the guide plates run parallel to the flow direction of the steam. (DG/PB) [de

  17. PWR steam-side chemistry follow program. Final report

    International Nuclear Information System (INIS)

    Economy, G.; Wootten, M.J.

    1982-08-01

    Denting is the diametral reduction of Inconel 600 tubes at the support plates of several nuclear steam generators during operation. This tube deformation was shown to be caused by the expansion forces resulting from formation of voluminous oxide generated by corrosion of the carbon steel support plate. The denting phenomenon and potential methods for its inhibition were investigated in the laboratory using isothermal capsules and heated crevice (heat transfer) testing at temperatures relevant to operating steam generators. Both test methods simulate the tube-support plate geometry and materials. Mathematical models were developed to predict the denting behavior of isothermal capsules. Three additives were investigated as potential denting inhibitors. Soaking with calcium hydroxide or sodium phosphate under heat transfer conditions did not inhibit denting when the environment was recontaminated, in contrast to similar soaks in boric acid which inhibited denting for two to four weeks following recontamination. When the boric acid soak was followed by on-line boric acid treatment, inhibition was maintained

  18. LMFBR steam generators in the United Kingdom

    International Nuclear Information System (INIS)

    Anderson, R.; Hayden, O.

    2002-01-01

    Experience has been gained in the UK on the operation of LMFBR Steam Generator Units (SGU) over a period of 20 years from the Dounreay Fast Reactor (DFR) and the Prototype Fast Reactor (PFR). The DFR steam generator featured a double barrier and therefore did not represent a commercial design. PFR, however, faced the challenge of a single wall design and it is experience from this which is most valuable. The PFR reactor went critical in March 1974 and the plant operating history since then has been dominated by experience with leaks in the tube to tube plate welds of the high performance U-tubes SGU's. Operation at high power using the full complement of three secondary sodium circuits was delayed until July 1976 by the occurrence of leaks in the tube to tube plate welds of the superheater and reheater units which are fabricated in stainless steel. Repairs were carried out to the two superheaters and they were returned to service. The reheater tube bundle was removed from circuit after sodium was found to have entered the steam side. When the sodium had been removed and inspection carried out it was decided not to recover the unit. Since 1976 the remaining five stainless steel units have operated satisfactorily. This year a replacement reheater unit has been installed. This is of a new design in 9-Cr-Mo ferritic steel using a sleeve through which the steam tube passes to eliminate the tube to tube plate weld. Despite a few early leaks in evaporator tube to tube plate welds up to 1979, these failures did not initially present a major problem. However, in 1980 the rate of evaporator weld failures increased and despite the successful application of a shot peening process to eliminate stress corrosion failures from the water side of the weld, failures traced to the sodium side continued. A sleeving process was developed for application to complete evaporator units on a production basis with the objective of bypassing the welds at each end of the 500 tubes. The decision

  19. Steam generator for pressurized-water reactors

    International Nuclear Information System (INIS)

    Michel, E.

    1971-01-01

    In the steam generator for a PWR the central fall space of a U-tube bundel heat exchanger is used as a preliminary cyclon separator. The steam escaping upwards, which is largely free of water, can flow through the residual heating surface, i.e. the U-tube turns. In this way substantial drying and less superheating by the heat still added becomes possible. In its upper part the central fall space for the water separated in the preliminary separator, enclosed by a cylindrical guide wall and the U-tube bundle, is provided with tangential inlet slots. Through these, the water-steam mixture steams out of the section of the vertical legs of the U-tube bundle into the fall space. Above the inlet slots the rising space is closed by means of a turn-round plate. At the lower end of the guide wall outlet, slots are provided for the water flowing downwards and radially outwards into the unfilled space. (DG/PB) [de

  20. Moving blade for steam turbines with axial flow

    International Nuclear Information System (INIS)

    Raschke, K.; Wehle, G.

    1976-01-01

    The invention concerns the improvement of the production of moving blades for steam turbines with axial flow, especially of multi-blades produced by welding of the top plates. It is proposed to weld the top plates before the moving blades are fitted into the rotor. Welding is this made much easier and can be carried out under protective gas and with better results. (UWI) [de

  1. Sludge cleaning in the steam generators: sludge Lancing e IBL

    International Nuclear Information System (INIS)

    Montoro, E.; Gonzalez, S.; Calderon, N.

    2013-01-01

    IBERDROLA Engineering and Construction has echoed the need for plants to remove oxide deposits (sludge) located on the secondary side, on the bottom plate and into the tube bundle steam steam generators. Therefore, and with its partner SAVAC SRA has developed a specific system consisting of applying a capillary water at very high pressure applied directly to the location of these oxides. (Author)

  2. Effectiveness of a steam cleaning unit for disinfection in a veterinary hospital.

    Science.gov (United States)

    Wood, Cheryl L; Tanner, Benjamin D; Higgins, Laura A; Dennis, Jeffrey S; Luempert, Louis G

    2014-12-01

    To evaluate whether the application of steam to a variety of surface types in a veterinary hospital would effectively reduce the number of bacteria. 5 surface types. Steam was applied as a surface treatment for disinfection to 18 test sites of 5 surface types in a veterinary hospital. A pretreatment sample was obtained by collection of a swab specimen from the left side of each defined test surface. Steam disinfection was performed on the right side of each test surface, and a posttreatment sample was then collected in the same manner from the treated (right) side of each test surface. Total bacteria for pretreatment and posttreatment samples were quantified by heterotrophic plate counts and for Staphylococcus aureus, Pseudomonas spp, and total coliforms by counts on selective media. Significant reductions were observed in heterotrophic plate counts after steam application to dog runs and dog kennel floors. A significant reduction in counts of Pseudomonas spp was observed after steam application to tub sinks. Bacterial counts were reduced, but not significantly, on most other test surfaces that had adequate pretreatment counts for quantification. Development of health-care-associated infections is of increasing concern in human and veterinary medicine. The application of steam significantly reduced bacterial numbers on a variety of surfaces within a veterinary facility. Steam disinfection may prove to be an alternative or adjunct to chemical disinfection within veterinary practices.

  3. Performance and endurance of a high temperature PEM fuel cell operated on methanol reformate

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Grigoras, Ionela; Zhou, Fan

    2014-01-01

    This paper analyzes the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC) at varying temperatures, ranging from 140 °C to 180 °C. For the study, a H3PO4 – doped polybenzimidazole (PBI) – based membrane electrode assembly (MEA......) of 45 cm2 active surface area from BASF was employed. The study showed overall negligible effects of methanol-water vapor mixture slips on performance, even at relatively low simulated steam methanol reforming conversion of 90%, which corresponds to 3% methanol vapor by volume in the anode gas feed....... Temperature on the other hand has significant impact on the performance of an HT-PEMFC. To assess the effects of methanol-water vapor mixture alone, CO2 and CO are not considered in these tests. The analysis is based on polarization curves and impedance spectra registered for all the test points. After...

  4. CATHENA analysis of CANDU 6 steam generators for steam main break at a remote location

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2009-07-01

    CATHENA (Canadian Algorithm for THErmalhydraulic Network Analysis) is a nonequilibrium, two-phase, two fluid network analysis code that has been in use for over two decades by various groups in Canada and around the world. It is the primary Thermalhydraulics network analysis tool used by Atomic Energy Canada Ltd. (AECL) in the design, safety and licensing analysis of power and research reactors as well as test facilities. In the thermalhydraulic model, the liquid and vapor phases may have different pressures, velocities, and temperatures. The objective of the present paper is to present the detailed modeling of a CANDU 6 Steam Generator (SG) using the transient, thermalhydraulics network code CATHENA. The model represents the secondary side, primary side and the main steam system including the main steam line up to the assumed break location. The present model is designed such that the transient pressure drops across Tube Support Plates (TSP) could be extracted. The resistances of degraded/fouled TSPs were modeled by using the increased/reduced flow area of the TSPs. CATHENA then calculates the flow resistance in two-phase flow based on the area contraction/expansion at the TSPs. Three sets of simulations were performed; one with the degraded steam generator data provided by the utility users, and the other two with waterlanced (cleaned with high pressure water jet) TSPs. One run assumed the flow area increased by 25 percent, the other run assumed the flow area increased by 50 percent. on the hot side of the SG. No significant changes in the break discharge rates were observed between the runs. However, the steam generator downcomer flow for the waterlanced case did not reverse during the blowdown as was calculated for the degraded case. As expected, the pressure drop across the TSPs was decreased in the waterlanced cases comparing with degraded cases. The CATHENA simulation provides estimates of the velocity, density, and quality in the tube bundle as well as

  5. Solar energy for steam generation in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    De Carvalho, Jr, A V; Orlando, A DeF; Magnoli, D

    1979-05-01

    Steam generation is a solar energy application that has not been frequently studied in Brazil, even though for example, about 10% of the national primary energy demand is utilized for processing heat generation in the range of 100 to 125/sup 0/C. On the other hand, substitution of automotive gasoline by ethanol, for instance, has received much greater attention even though primary energy demand for process heat generation in the range of 100 to 125/sup 0/C is of the same order of magnitude than for total automotive gasoline production. Generation of low-temperature steam is analyzed in this article using distributed systems of solar collectors. Main results of daily performance simulation of single flat-plate collectors and concentrating collectors are presented for 20/sup 0/S latitude, equinox, in clear days. Flat plate collectors considered are of the aluminum roll-bond absorber type, selective surface single or double glazing. Considering feedwater at 20/sup 0/C, saturated steam at 120/sup 0/C and an annual solar utilization factor of 50%, a total collector area of about 3,000 m/sup 2/ is necessary for the 10 ton/day plant, without energy storage. A fuel-oil back-up system is employed to complement the solar steam production, when necessary. Preliminary economic evaluation indicates that, although the case-study shows today a long payback period relative to subsidized fuel oil in the domestic market (over 20 years in the city of Rio de Janeiro), solar steam systems may be feasible in the medium term due to projected increase of fuel oil price in Brazil.

  6. Steam generator operation and maintenance

    International Nuclear Information System (INIS)

    Lee, C.K.

    2004-01-01

    Corrosion of steam generator tube has resulted in the need for extensive repair and replacement of steam generators. Over the past two decades, steam generator problems in the United States were viewed to be one of the most significant contributor to lost generation in operating PWR plants. When the SGOG-I (Steam Generator Owners Groups) was formed in early 1977, denting was responsible for almost 90% of the tube plugging. By the end of 1982, this figure was reduced to less than 2%. During the existence of SGOG-II (from 1982 to 1986), IGA/SCC (lntergranular Attack/Stress Corrosion Cracking) in the tube sheet, primary side SCC, pitting, and fretting surfaced as the primary causes of tube degradation. Although significant process has been made with wastage and denting, the utilities experience shows that the percentage of reactors plugging tubes and the percentage of tubes being plugged each year has remained relatively constant. The diversity of the damage mechanisms means that no one solution is likely to resolve all problems. The task of maintaining steam generator integrity continues to be formidable and challenging. As the older problems were brought under control, many new problems emerged. SGOG-II (Steam Generator Owners Group program from 1982 to 1986) has focused on these problem areas such as tube stress corrosion cracking (SCC) and intergranular attack (IGA) in the open tube sheet crevice, primary side tube cracking, pitting in the lower span, and tube fretting in preheated section and anti-vibration bar (AVB) locations. Primary Water Stress Corrosion Cracking (PWSCC) in the tube to tubesheet roll transition has been a wide spread problem in the Recirculation Steam Generators (RSG) during this period. Although significant progress has been made in resolving this problem, considerable work still remains. One typical problem in the Once Through Steam Generator (OTSG) was the tube support plate broached hole fouling which affects the OTSG steam generating

  7. Characterisation of micro direct methanol fuel cells with silicon plate supported integrated ionomer membranes

    DEFF Research Database (Denmark)

    Larsen, Jackie Vincent; Dalslet, Bjarke Thomas; Kallesee, C.

    2013-01-01

    This work deals with the investigation and fabrication of Micro Direct Methanol Fuel Cells (μDMFC). They are investigated as a possible alternative for zinc-air batteries in small size consumer devices such as hearing aids. In such devices the conventional rechargeable batteries such as lithium......-ion batteries have insufficiently low energy density in the range 240 Wh/L to 300 Wh/L Methanol is a promising fuel for such devices due to the high energy density, with pure methanol having an energy density of 4400 Wh/L. Using a liquid fuel also allows refueling, which can be achieved much faster than battery...

  8. Dynamic simulation of a furnace of steam reforming of natural gas

    International Nuclear Information System (INIS)

    Acuna, A; Fuentes, C; Smith, C A

    1999-01-01

    Steam reforming of natural gas is a very important industrial process in refineries and ammonia and methanol plants. Hydrogen is produced by reforming methane with steam. This hydrogen is essential in the hydro-treating process in the refineries thus, it is important to supervise and control the performance of the hydrogen plant. Mathematical models of refineries and chemical plants are used to simulate the behavior of the process units. However, the models especially of reactors like reformers are not very reliable. This paper presents a dynamic model of a furnace-reactor. The simulation results are validated with industrial data

  9. Utilization of methanol for polymer electrolyte fuel cells in mobile systems

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, V M [Research Centre Juelich (KFA), Inst. of Energy Process Engineering (Germany); Broeckerhoff, P [Research Centre Juelich (KFA), Inst. of Energy Process Engineering (Germany); Hoehlein, B [Research Centre Juelich (KFA), Inst. of Energy Process Engineering (Germany); Menzer, R [Research Centre Juelich (KFA), Inst. of Energy Process Engineering (Germany); Stimming, U [Research Centre Juelich (KFA), Inst. of Energy Process Engineering (Germany)

    1994-04-01

    The constantly growing volume of road traffic requires the introduction of new vehicle propulsion systems with higher efficiency and drastically reduced emission rates. As part of the fuel cell programme of the Research Centre Juelich a vehicle propulsion system with methanol as secondary energy carrier and a polymer electrolyte membrane fuel cell (PEMFC) as the main component for energy conversion is developed. The fuel gas is produced by a heterogeneously catalyzed steam reforming reaction in which methanol is converted to H[sub 2], CO and CO[sub 2]. The required energy is provided by the catalytic conversion of methanol for both heating up the system and reforming methanol. The high CO content of the fuel gas requires further processing of the gas or the development of new electrocatalysts for the anode. Various Pt-Ru alloys show promising behaviour as CO-tolerant anodes. The entire fuel cell system is discussed in terms of energy and emission balances. The development of important components is described and experimental results are discussed. (orig.)

  10. Chemical-cleaning process evaluation: Westinghouse steam generators. Final report

    International Nuclear Information System (INIS)

    Cleary, W.F.; Gockley, G.B.

    1983-04-01

    The Steam Generator Owners Group (SGOG)/Electric Power Research Institute (EPRI) Steam Generator Secondary Side Chemical Cleaning Program, under develpment since 1978, has resulted in a generic process for the removal of accumulated corrosion products and tube deposits in the tube support plate crevices. The SGOG/EPRI Project S150-3 was established to obtain an evaluation of the generic process in regard to its applicability to Westinghouse steam generators. The results of the evaluation form the basis for recommendations for transferring the generic process to a plant specific application and identify chemical cleaning corrosion guidelines for the materials in Westinghouse Steam Generators. The results of the evaluation, recommendations for plant-specific applications and corrosion guidelines for chemical cleaning are presented in this report

  11. Methanol Reforming over Cobalt Catalysts Prepared from Fumarate Precursors: TPD Investigation

    Directory of Open Access Journals (Sweden)

    Eftichia Papadopoulou

    2016-02-01

    Full Text Available Temperature-programmed desorption (TPD was employed to investigate adsorption characteristics of CH3OH, H2O, H2, CO2 and CO on cobalt-manganese oxide catalysts prepared through mixed Co-Mn fumarate precursors either by pyrolysis or oxidation and oxidation/reduction pretreatment. Pyrolysis temperature and Co/Mn ratio were the variable synthesis parameters. Adsorption of methanol, water and CO2 was carried out at room temperature. Adsorption of H2 and H2O was carried out at 25 and 300 °C. Adsorption of CO was carried out at 25 and 150 °C. The goal of the work was to gain insight on the observed differences in the performance of the aforementioned catalysts in methanol steam reforming. TPD results indicated that activity differences are mostly related to variation in the number density of active sites, which are able to adsorb and decompose methanol.

  12. Strategic elements of steam cycle chemistry control practices at TXU's Comanche Peak steam electric station

    International Nuclear Information System (INIS)

    Fellers, B.; Stevens, J.; Nichols, G.

    2002-01-01

    Early industry experience defined the critical importance of Chemistry Control Practices to maintaining long-term performance of PWR steam generators. These lessons provided the impetus for a number of innovations and alternate practices at Comanche Peak. For example, advanced amine investigations and implementation of results provided record low iron transport and deposition. The benefits of the surface-active properties of dimethyl-amine exceeded initial expectations. Operation of pre-coat polishers and steam generator blowdown demineralizers in the amine cycle enabled optimization of amine concentrations and stable pH control. The strategy for coordinated control of oxygen and hydrazine dosing complemented the advanced amine program for protective oxide stabilization. Additionally, a proactive chemical cleaning was performed on Unit 1 to prevent degradations from general fouling of steam generator tube-tube support plate (TSP) and top-of-tubesheet (TTS) crevices. This paper shares the results of these innovations and practices. Also, the bases, theory, and philosophy supporting the strategic elements of program will be presented. (authors)

  13. Automated Diagnosis and Classification of Steam Generator Tube Defects

    International Nuclear Information System (INIS)

    Garcia, Gabe V.

    2004-01-01

    A major cause of failure in nuclear steam generators is tube degradation. Tube defects are divided into seven categories, one of which is intergranular attack/stress corrosion cracking (IGA/SCC). Defects of this type usually begin on the outer surface of the tubes and propagate both inward and laterally. In many cases these defects occur at or near the tube support plates. Several different methods exist for the nondestructive evaluation of nuclear steam generator tubes for defect characterization

  14. Pd-Ag membrane reactor for steam reforming reactions: a comparison between different fuels

    NARCIS (Netherlands)

    Gallucci, F.; Basile, A.

    2008-01-01

    The simulation of a dense Pd-based membrane reactor for carrying out the methane, the methanol and the ethanol steam reforming (SR) reactions for pure hydrogen production is performed. The same simulation is also performed in a traditional reactor. This modelling work shows that the use of membrane

  15. Metal membrane-type 25-kW methanol fuel processor for fuel-cell hybrid vehicle

    Science.gov (United States)

    Han, Jaesung; Lee, Seok-Min; Chang, Hyuksang

    A 25-kW on-board methanol fuel processor has been developed. It consists of a methanol steam reformer, which converts methanol to hydrogen-rich gas mixture, and two metal membrane modules, which clean-up the gas mixture to high-purity hydrogen. It produces hydrogen at rates up to 25 N m 3/h and the purity of the product hydrogen is over 99.9995% with a CO content of less than 1 ppm. In this fuel processor, the operating condition of the reformer and the metal membrane modules is nearly the same, so that operation is simple and the overall system construction is compact by eliminating the extensive temperature control of the intermediate gas streams. The recovery of hydrogen in the metal membrane units is maintained at 70-75% by the control of the pressure in the system, and the remaining 25-30% hydrogen is recycled to a catalytic combustion zone to supply heat for the methanol steam-reforming reaction. The thermal efficiency of the fuel processor is about 75% and the inlet air pressure is as low as 4 psi. The fuel processor is currently being integrated with 25-kW polymer electrolyte membrane fuel-cell (PEMFC) stack developed by the Hyundai Motor Company. The stack exhibits the same performance as those with pure hydrogen, which proves that the maximum power output as well as the minimum stack degradation is possible with this fuel processor. This fuel-cell 'engine' is to be installed in a hybrid passenger vehicle for road testing.

  16. Steam generator secondary side chemical cleaning at Gentilly-2

    International Nuclear Information System (INIS)

    Plante, S.

    2006-01-01

    After more than 20 years of operation, the secondary side of the four steam generators at Gentilly-2 were chemically cleaned during the 2005 annual outage. The FRAMATOME ANP high temperature cleaning process used to remove magnetite loading involved stepwise injection of solvent with PHT temperature in the range 160 o C to 175 o C. The heat required to maintain the PHT temperature was provided by the operation of the main PHT pumps and the reactor core residual heat. The temperature control was accomplished by the shutdown cooling system heat exchangers. A total of 1280 kg of magnetite was removed from the four steam generators. A copper-cleaning step was applied after the iron step. The PHT has been cooled down and the steam generators drained to temporary tanks and dried in preparation of the copper step. The process has been applied at room temperature, two boilers at a time. The solvent removed a total of 116 kg of copper. During the iron step, steam flow to the feedwater tank chemically contaminate the Balance Of Plant (BOP) systems. The isolation of this path should have been part of the G2 procedures. Around 700 m3 of water had to be drained to interim storage tanks for subsequent resin treatment before disposal. Visual inspection of BO1 tubesheet and first support plate showed clean surfaces without measurable sludge pile. Upper support plates visual inspection of BO4 revealed that broach holes blockage reported in 2000 is still present in peripheral area. Following the plant restart, the medium range level measurement instability observed since several years for BO3 was no more present. As anticipated, it also has been observed that the medium and wide range level measurements have shifted down as a result of downcomer flow increase after the cleaning. The cleaning objectives were achieved regarding the fouling reduction on the steam generators secondary side but broach holes blockage of the upper support plate is still present in periphery. (author)

  17. Replacement divider plate performance under LOCA loading

    International Nuclear Information System (INIS)

    Huynk, H.M.; MClellan, G.H.; Schneider, W.G.

    1997-01-01

    A primary divider plate in a nuclear steam generator is required to perform its partitioning function with a minimum of cross leakage, without degradation in operating performance and without loss of structural integrity resulting from normal and accident loading. The design of the replacement divider plate for normal operating conditions is discussed in some detail in reference 1 and 2. This paper describes the structural response of the replacement divider plate to the severe loading resulting from a burst primary pipe. The loads for which the divider plate structural performance must be evaluated are mild to severe differential pressure transients resulting from several postulated sizes and types of pipe break scenarios. In the unlikely event of a severe Loss of Coolant Accident (LOCA) the divider plate or parts thereof must not exit the steam generator nor completely block the outlet nozzle. For the milder LOCA loads, the integrity of the divider plate and seat bars must be maintained. Analysis for the milder LOCA loads was carried out employing a conservative approach which ignores the actual interaction between the structure and the primary fluid. For these load cases it was shown that the divider plate does not become disengaged from the seat bars. For the more severe pipe breaks, the thermal-hydraulic analysis was coupled iteratively with the structural analysis, thereby taking into account divider plate deformation, in order to obtain a better prediction of the behaviour of the divider plate. In this manner substantial reduction in divider plate response to the more severe LOCA loading was achieved. It has been shown that, for the case of a postulated large LOCA (100% reactor inlet header), the disengagement of the divider plate from the seat bars resulted in an opening smaller than 1% of the divider plate area. (author)

  18. Eddy current testing of steam generator tubes

    International Nuclear Information System (INIS)

    Neumaier, P.

    1981-01-01

    A rotating probe is described for improving the inspection of tubes and end plate in steam generators. The method allows a representation of the whole defect, consequently the observer is able to determine directly the type of defect, signal processing in-line or off-line is possible [fr

  19. Comparative study of hydrogen and methanol as energy carriers

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Anna

    1998-06-01

    This report has been written with the purpose to compare hydrogen and methanol, with gasoline, as energy carriers for new energy systems in the future. This energy system must satisfy the demands for sustainable development. The report focuses on motor vehicle applications. A few different criteria has been developed to help form the characterisation method. The criteria proposed in this thesis are developed for an environmental comparison mainly based on emissions from combustion. The criteria concerns the following areas: Renewable resources, The ozone layer, The greenhouse effect, The acidification, and Toxic substances. In many ways, hydrogen may seem as a very good alternative compared with gasoline and diesel oil. Combustion of hydrogen in air results in water and small amounts of oxides of nitrogen. In this report, hydrogen produced from renewable resources is investigated. This is necessary to fulfill the demands for sustainable development. Today, however, steam reforming of fossil fuels represent 99% of the hydrogen production market. Problem areas connected with hydrogen use are for instance storage and distribution. Methanol has many advantages, while comparing methanol and gasoline, like lower emissions of nitrogen oxides and hydrocarbons, limited emissions of carbon dioxide and no sulphur content. Methanol can be produced from many different resources, for example natural gas, naphtha, oil, coal or peat, and biomass. To meet demands for sustainable production, methanol has to be produced from biomass Examination paper. 32 refs, 20 figs, 13 tabs

  20. Evaluation of Oconee steam-generator debris. Final report

    International Nuclear Information System (INIS)

    Rigdon, M.A.; Rubright, M.M.; Sarver, L.W.

    1981-10-01

    Pieces of debris were observed near damaged tubes at the 14th support plate elevation in the Oconee 1-B steam generator. A project was initiated to evaluate the physical and chemical nature of the debris, to identify its source, and to determine its role in tube damage at this elevation. Various laboratory techniques were used to characterize several debris and mill scale samples. Data from these samples were then compared with each other and with literature data. It was concluded that seven of eight debris samples were probably formed in the steam generator. Six of these samples were probably formed by high temperature aqueous corrosion early in the life of the steam generator. The seventh sample was probably formed by the deposition and spalling of magnetite on the Inconel steam generator tubes. None of the debris samples resembled any of the mill scale samples

  1. Stress analysis of pressurized water reactor steam generator tube denting phenomena. Interim report

    International Nuclear Information System (INIS)

    Thomas, J.M.; Cipolla, R.C.; Ranjan, G.V.; Derbalian, G.

    1978-07-01

    In some Pressurized Water Reactor (PWR) steam generators, a corrosion product has formed on the carbon steel support plate in the crevice between the tube and support plate. The corrosion product occupies more volume than the original metal; the tube-to-support plate crevice volume is thus consumed with corrosion product, and further corrosive action results in a radially inward force on the tube and a radially outward force on the corroding support plate. This has resulted in indentation (''denting'') of the tube, accompanied by occasional cracking. Large in-plane deformation and cracking of support plates has also been observed in the most severely affected plants along with some serious side effects, such as deformation and cracking of inner row tube U-bends caused by support plate movement. Mechanical aspects of the tube denting phenomena have been studied using analytical models. The models used ranged from closed form analytical solutions to state-of-the-art numerical elastic-plastic computer program for moderate strains. It was found that tube dents, such as those observed in operating steam generators, are associated with yielding of both the tubes and support plates. Also studied were the stresses in tube U-bends caused by support plate flow slot deformation

  2. On the reliability of steam generator performance at nuclear power plants with WWER type reactors

    International Nuclear Information System (INIS)

    Styrikovich, M.A.; Margulova, T.Kh.

    1974-01-01

    The problem of ensuring reliable operation of steam generators in a nuclear power plant with a water-cooled, water-moderated reactor (WWER) was studied. At a nuclear power plant with a vertical steam generator (specifically, a Westinghouse product) the steam generator tubes were found to have been penetrated. Shutdown was due to corrosion disintegration of the austenitic stainless steel, type 18/8, used as pipe material for the heater surface. The corrosion was the result of the action of chlorine ions concentrated in the moisture contained in the iron oxide films deposited in low parts of the tube bundle, directly at the tube plate. Blowing through did not ensure complete removal of the film, and in some cases the construction features of the steam generator made removal of the film practically impossible. Replacement of type 18/8 stainless steel by other construction material, e.g., Inconel, did not give good results. To ensure reliable operation of vertical steam generators in domestic practice, the generators are designed without a low tube plate (a variant diagram of the vertical steam generator of such construction for the water-cooled, water-moderated reactor 1000 is presented). When low tube plates are used the film deposition is intolerable. For organization of a non-film regime a complex treatment of the feed water is used, in which the amount of complexion is calculated from the stoichmetric ratios with the composition of the feed water. It is noted that, if 100% condensate purification is used with complexon processing of the feed water to the generator, we can calculate the surface of the steam-generator heater without considering the outer placement on the tubes. In this the cost of the steam generator and all the nuclear power plants with WWER type reactors is decreased even with installation of a 100% condensate purification. It is concluded that only simultaneous solution of construction and water-regime problems will ensure relaible operation of

  3. Steam cracking and methane to olefins: Energy use, CO2 emissions and production costs

    NARCIS (Netherlands)

    Ren, T.; Patel, M.K.|info:eu-repo/dai/nl/18988097X; Blok, K.|info:eu-repo/dai/nl/07170275X

    2008-01-01

    While most olefins (e.g., ethylene and propylene) are currently produced through steam cracking routes, they can also possibly be produced from natural gas (i.e., methane) via methanol and oxidative coupling routes. We reviewed recent data in the literature and then compared the energy use, CO2

  4. Water chemistry and corrosion in water-steam circuits of nuclear power plants

    International Nuclear Information System (INIS)

    Gardent, R.; Menet, O.

    1981-01-01

    The water and steam circuits of steam generators in pressurized-water nuclear power plants are described together with the mechanism of denting, and the corrosion of spacer plates that leads to cracks in tubes by constriction. The different chemical specifications applicable to the water of the secondary circuit of the generators in normal operation and on first commissioning are listed. The results obtained and the measurements of chemical values taken in operation on the water in the secondary circuits of steam generators at Fessenheim and Bugey are presented [fr

  5. A connection of the steam generator feedwater section of WWER type nuclear power plants

    International Nuclear Information System (INIS)

    Matal, O.; Sadilek, J.

    1989-01-01

    In the feedwater piping of each steam generator, a plate for additional water pressure reduction is inserted before the first closing valve. During a steady water flow, the plate gives rise to a constant hydraulic resistance, bringing about steady reduction of the feedwater pressure; this also contributes to a stabilization of the feedwater flow rate into the steam generator. The control valve thus is stressed by minimal hydrodynamic forces. In this manner its load is decreased, its vibrations are damped, and the frequency of failures - and thereby the frequency of the nuclear power plant unit outages -is reduced. (J.P.). 1 fig

  6. Simulation and design of distillation units for treatment of sulfite pulping condensates to recover methanol and furfural. Part II. Applicability of multiple-effect distillation using live steam

    Energy Technology Data Exchange (ETDEWEB)

    Aly, G.; Zacchi, G.

    1979-06-01

    A distillation unit has been designed for a capacity of 73 t/h of condensate and for at least 90% recovery of the contaminating organics. This unit consists of three columns: a primary stripper to remove volatile organics and two upgrading columns to purify the methanol and furfural byproducts. Three different energy-saving alternatives for satisfying the energy requirements have been studied: utilisation of secondary steam from the evaporation plant, and application of the principle of multi-effect distillation in one-stripper and in two-stripper configurations. Investment cost needed in all alternatives amounts to 5.5 to 6.0 MCr (millions of Swedish Crowns) while operating cost varies between 0.8 to 3.1 MCr. The first design alternative has a payoff period of 2.3 years while the two multi-effect distillation alternatives have a payoff period of about 3 years.

  7. Divider plate leak inspections using an acoustic tool 'ALIS'

    International Nuclear Information System (INIS)

    Kowalewski, J.; Colbert, M.

    1998-01-01

    Divider plate leakage in the primary head of steam generators may be a contributor to high Reactor Inlet Header Temperature (RIHT) which can have a negative effect on the operation of a plant. A method to provide quick information of divider plate leakage can be very useful in helping operators to make timely and cost effective repair and maintenance decisions. As part of a CANDU Owners Group (COG) funded program, a novel acoustic tool for performing inspections in empty steam generators during a shutdown has been developed and successfully demonstrated by Ontario Hydro Technologies (OHT). The basic principle of this technique utilizes sound transmission through the leakage paths of a divider plate assembly for creating a graphic image which reveals the locations and relative sizes of leaks. This is accomplished by injecting one side of the primary head with a series of airborne, ultrasonic sound bursts while scanning the divider plates from the opposite side and collecting transmitted sound pressure levels. Once a scan is completed the results are processed and displayed graphically as a color mapping of the entire divider plate assembly showing an image of the leakage locations and relative severity. The special transducers of the acoustic leak inspection system (ALIS) are installed through the manways of the steam generator at both sides of the primary head. These are clamped to the tube sheet and operated from a convenient remote location within the containment building. This process minimizes radiation exposure of the workers, as well, it reduces risk of contamination of the ALIS equipment. The current version of this tool performs the scans by remote manual control. (author)

  8. Chemical cleaning of nuclear (PWR) steam generators

    International Nuclear Information System (INIS)

    Welty, C.S. Jr.; Mundis, J.A.

    1982-01-01

    This paper reports on a significant research program sponsored by a group of utilities (the Steam Generator Owners Group), which was undertaken to develop a process to chemically remove corrosion product deposits from the secondary side of pressurized water reactor (PWR) power plant steam generators. Results of this work have defined a process (solvent system and application methods) that is capable of removing sludge and tube-to-tube support plate crevice corrosion products generated during operation with all-volatile treatment (AVT) water chemistry. Considers a plant-specific test program that includes all materials in the steam generator to be cleaned and accounts for the physical locations (proximity and contact) of those materials. Points out that prior to applying the process in an operational unit, the utility, with the participation of the NSSR vendor, must define allowable total corrosion to the materials of construction of the unit

  9. System for removing sludges from a steam generator

    International Nuclear Information System (INIS)

    Hickman, R.A.; Tolino, R.W.

    1977-01-01

    The invention relates to a process for removing sludge from a steam generator comprising a tube plate at the bottom end of a cylinder and a cluster of heat exchange tubes fitted to this tube plate and extending upwards from it. The cylinder has an access opening above this tube plate. A liquid jet is applied at a tangent to the cylinder above the tube plate so as to form a cicumferential flow of liquid at the external end of this plate. This flow is taken up and sucked out of the cylinder by a suction appliance and, at the same time, a nozzle with holes for liquid jets is moved crosswise to these tubes above the tube plate whilst directing a liquid jet against the tubes and towards the cicumferential liquid flow so as to wash away any deposits detached from the lower ends of the tubes and located in this circular flow of liquid to be immediately removed by the suction appliance [fr

  10. Growth inhibition of periphytic diatoms by methanol extracts of sponges and holothurians

    Digital Repository Service at National Institute of Oceanography (India)

    Mokashe, S.S.; Garg, A; Anil, A; Wagh, A

    Crude methanol extracts of a holothurian Holothuria leucospilota, and two sponges Craniella sp. and Ircinia ramosa were tested for their inhibitory effects on the growth of two marine diatoms, Navicula subinflata and N. crucicula, by diatom plating...

  11. Control and Experimental Characterization of a Methanol Reformer for a 350 W High Temperature Polymer Electrolyte Membrane Fuel Cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Jensen, Hans-Christian Becker

    , i.e. cathode and anode gas flows and temperature by using mass flow controllers and controlled heaters. Using this system the methanol reformer is characterized in its different operating points, both steady-state but also dynamically. Methanol steam reforming is a well known process, and provides...... and burner and the behaviour of the CO concentration of the reformate gas....... the high temperature waste gas from a cathode air cooled 45 cell HTPEM fuel cell stack. The MEAs used are BASF P2100 which use phosphoric acid doped polybenzimidazole type membranes; an MEA with high CO tolerance and no complex humidity requirements. The methanol reformer used is integrated into a compact...

  12. Synergetic mechanism of methanol–steam reforming reaction in a catalytic reactor with electric discharges

    International Nuclear Information System (INIS)

    Kim, Taegyu; Jo, Sungkwon; Song, Young-Hoon; Lee, Dae Hoon

    2014-01-01

    Highlights: • Methanol–steam reforming was performed on Cu catalysts under an electric discharge. • Discharge had a synergetic effect on the catalytic reaction for methanol conversion. • Discharge lowered the temperature for catalyst activation or light off. • Discharge controlled the yield and selectivity of species in a reforming process. • Adsorption triggered by a discharge was a possible mechanism for a synergetic effect. - Abstract: Methanol–steam reforming was performed on Cu/ZnO/Al 2 O 3 catalysts under an electric discharge. The discharge occurred between the electrodes where the catalysts were packed. The electric discharge was characterized by the discharge voltage and electric power to generate the discharge. The existence of a discharge had a synergetic effect on the catalytic reaction for methanol conversion. The electric discharge provided modified reaction paths resulting in a lower temperature for catalyst activation or light off. The discharge partially controlled the yield and selectivity of species in a reforming process. The aspect of control was examined in view of the reaction kinetics. The possible mechanisms for the synergetic effect between the catalytic reaction and electric discharge on methanol–steam reforming were addressed. A discrete reaction path, particularly adsorption triggered by an electric discharge, was suggested to be the most likely mechanism for the synergetic effect. These results are expected to provide a guide for understanding the plasma–catalyst hybrid reaction

  13. Changes on the Physical-Chemical Properties of Kue delapan Jam on Various Steaming Time

    Directory of Open Access Journals (Sweden)

    Sri Agustini

    2014-10-01

    Full Text Available This research intended to study browning reaction between glucose, fructose, and lipids with amino acids in real system during making Kue Delapan Jam. Research applied completely randomized design with steaming time as treatment ( 2, 4, 6, and 8 hours with 3 replication. The development of color and browning index were ivestigated by using lightness, redness, yellowness, and total color difference (TCD during reaction,  and the absorbance of methanol extracts was measured at 420 nm in 40.0 mm silica. The development of texture was monitored by using Bookfield texture analyzer. Test results showed that steaming time influenced the color, browning index, texture, protein, and fat content of the cake significantly.  Steaming time has no effect on water content. There were positive correlation between steaming time with TDC, redness,  texture, and browning index during course. While for lightness, yellowness, pH, protein, and fat content indicated negative correlation. Changes on texture, TDC, browning index, protein, and fat content followed linear model.

  14. Development of the Integrated Hydrogen Production System Using Micro-structured Devices

    International Nuclear Information System (INIS)

    Jung Min Sohn; Young Chang Byun; Jun Yeon Cho; Youngwoon Kwon; Jaehoon Choe

    2006-01-01

    A plate-type integrated fuel processor, which consisted of three different micro-reactors which were a reformer with combustor, two heat exchangers and an evaporator with combustor, was developed for the hydrogen production as feed of over 100 W-grade PEMFC. The methanol steam reforming was chosen in our fuel processor to produce highly pure hydrogen. Our system could be operated without any external electric heat supply. Hydrogen which might come from off gas was used as the combustion fuel at initial stage and methanol was used during the steam reaction. Cu/Zn/Al 2 O 3 and Pt/Al 2 O 3 catalysts were chosen for steam reforming of methanol and the combustion and coated on microchannel-patterned stainless steel sheets. The performance of the fuel processor was tested for long-term use. The integrated system was operated consistently with methanol conversion of over 80.0 mol% at 300 C for 20 hrs without deactivation of catalyst. The maximum composition of hydrogen and production rate on dry basis was about 70 % and 1.7 L/min, respectively. The efficiency of our system was calculated based on the LHV of methanol and hydrogen. Overall thermal efficiency of our fuel processor was 59.5 % and thermal power of hydrogen was about 300 W. (authors)

  15. Predicting steam generator crevice chemistry

    International Nuclear Information System (INIS)

    Burton, G.; Strati, G.

    2006-01-01

    'Full text:' Corrosion of steam cycle components produces insoluble material, mostly iron oxides, that are transported to the steam generator (SG) via the feedwater and deposited on internal surfaces such as the tubes, tube support plates and the tubesheet. The build up of these corrosion products over time can lead to regions of restricted flow with water chemistry that may be significantly different, and potentially more corrosive to SG tube material, than the bulk steam generator water chemistry. The aim of the present work is to predict SG crevice chemistry using experimentation and modelling as part of AECL's overall strategy for steam generator life management. Hideout-return experiments are performed under CANDU steam generator conditions to assess the accumulation of impurities in hideout, and return from, model crevices. The results are used to validate the ChemSolv model that predicts steam generator crevice impurity concentrations, and high temperature pH, based on process parameters (e.g., heat flux, primary side temperature) and blowdown water chemistry. The model has been incorporated into ChemAND, AECL's system health monitoring software for chemistry monitoring, analysis and diagnostics that has been installed at two domestic and one international CANDU station. ChemAND provides the station chemists with the only method to predict SG crevice chemistry. In one recent application, the software has been used to evaluate the crevice chemistry based on the elevated, but balanced, SG bulk water impurity concentrations present during reactor startup, in order to reduce hold times. The present paper will describe recent hideout-return experiments that are used for the validation of the ChemSolv model, station experience using the software, and improvements to predict the crevice electrochemical potential that will permit station staff to ensure that the SG tubes are in the 'safe operating zone' predicted by Lu (AECL). (author)

  16. Steam generator waterlancing at DNGS

    International Nuclear Information System (INIS)

    Seppala, D.; Malaugh, J.

    1995-01-01

    Darlington Nuclear Generating Station (DNGS) is a four 900 MW Unit nuclear station forming part of the Ontario Hydro East System. There are four identical steam generators(SGs) per reactor unit. The Darlington SGs are vertical heat exchangers with an inverted U-tube bundle in a cylindrical shell. The DNGS Nuclear Plant Life Assurance Group , a department of DNGS Engineering Services have taken a Proactive Approach to ensure long term SG integrity. Instead of waiting until the tubesheets are covered by a substantial and established hard deposit; DNGS plan to clean each steam generator's tubesheet, first half lattice tube support assembly and bottom of the thermal plate every four years. The ten year business plan provides for cleaning and inspection to be conducted on all four SGs in each unit during maintenance outages (currently scheduled for every four years)

  17. Steam reforming of different biomass tar model compounds over Ni/Al_2O_3 catalysts

    International Nuclear Information System (INIS)

    Artetxe, Maite; Alvarez, Jon; Nahil, Mohamad A.; Olazar, Martin; Williams, Paul T.

    2017-01-01

    Highlights: • Order of reactivity: anisole > furfural > indene > phenol > toluene > methyl naphthalene. • Higher coke deposition for oxygenates (1.5–2.8%) than for aromatics (0.5–0.8%). • Amorphous coke is deposited for oxygenates and filamentous carbon for aromatics. • Ni content of 20 wt.% shows the higher conversion (90%) and H_2 potential (63%). - Abstract: This work focuses on the removal of the tar derived from biomass gasification by catalytic steam reforming on Ni/Al_2O_3 catalysts. Different tar model compounds (phenol, toluene, methyl naphthalene, indene, anisole and furfural) were individually steam reformed (after dissolving each one in methanol), as well as a mixture of all of them, at 700 °C under a steam/carbon (S/C) ratio of 3 and 60 min on stream. The highest conversions and H_2 potential were attained for anisole and furfural, while methyl naphthalene presented the lowest reactivity. Nevertheless, the higher reactivity of oxygenates compared to aromatic hydrocarbons promoted carbon deposition on the catalyst (in the 1.5–2.8 wt.% range). When the concentration of methanol is decreased in the feedstock and that of toluene or anisole is increased, the selectivity to CO is favoured in the gaseous products, thus increasing coke deposition on the catalyst and decreasing catalyst activity for the steam reforming reaction. Moreover, an increase in Ni loading in the catalyst from 5 to 20% enhances carbon conversion and H_2 formation in the steam reforming of a mixture of all the model compounds studied, but these values decrease for a Ni content of 40%. Coke formation also increased by increasing Ni loading, attaining its maximum value for 40% Ni (6.5 wt.%).

  18. Local properties of countercurrent stratified steam-water flow

    International Nuclear Information System (INIS)

    Kim, H.J.

    1985-10-01

    A study of steam condensation in countercurrent stratified flow of steam and subcooled water has been carried out in a rectangular channel/flat plate geometry over a wide range of inclination angles (4 0 -87 0 ) at several aspect ratios. Variables were inlet water and steam flow rates, and inlet water temperature. Local condensation rates and pressure gradients were measured, and local condensation heat transfer coefficients and interfacial shear stress were calculated. Contact probe traverses of the surface waves were made, which allowed a statistical analysis of the wave properties. The local condensation Nusselt number was correlated in terms of local water and steam Reynolds or Froude numbers, as well as the liquid Prandtl number. A turbulence-centered model developed by Theofanous, et al. principally for gas absorption in several geometries, was modified. A correlation for the interfacial shear stress and the pressure gradient agreed with measured values. Mean water layer thicknesses were calculated. Interfacial wave parameters, such as the mean water layer thickness, liquid fraction probability distribution, wave amplitude and wave frequency, are analyzed

  19. Corrosion of PWR steam generators

    International Nuclear Information System (INIS)

    Garnsey, R.

    1979-01-01

    Some designs of pressurized water reactor (PWR) steam generators have experienced a variety of corrosion problems which include stress corrosion cracking, tube thinning, pitting, fatigue, erosion-corrosion and support plate corrosion resulting in 'denting'. Large international research programmes have been mounted to investigate the phenomena. The operational experience is reviewed and mechanisms which have been proposed to explain the corrosion damage are presented. The implications for design development and for boiler and feedwater control are discussed. (author)

  20. Design and Control of High Temperature PEM Fuel Cell Systems using Methanol Reformers with Air or Liquid Heat Integration

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Sahlin, Simon Lennart

    2013-01-01

    The present work describes the ongoing development of high temperature PEM fuel cell systems fuelled by steam reformed methanol. Various fuel cell system solutions exist, they mainly differ depending on the desired fuel used. High temperature PEM (HTPEM) fuel cells offer the possibility of using...... methanol is converted to a hydrogen rich gas with CO2 trace amounts of CO, the increased operating temperatures allow the fuel cell to tolerate much higher CO concentrations than Nafion-based membranes. The increased tolerance to CO also enables the use of reformer systems with less hydrogen cleaning steps...... liquid fuels such as methanol, due to the increased robustness of operating at higher temperatures (160-180oC). Using liquid fuels such as methanol removes the high volume demands of compressed hydrogen storages, simplifies refueling, and enables the use of existing fuel distribution systems. The liquid...

  1. Ultrasonic imaging of tube/support structure of power plant steam generators

    International Nuclear Information System (INIS)

    Saniie, J.; Nagle, D.T.

    1987-01-01

    The corrosion and erosion of steam generator tubing in nuclear power plants can present problems of both safety and economics. In steam generators, the inconel tubes are fit loosely through holes drilled in carbon steel support plates. Corrosion is of particular concern with such tube/support plate structures. Non-protective magnetite can build up on the inner surface of the support plate holes, and allowed to continue unchecked, will fill the gap, eventually denting and fracturing the tube walls. Therefore, periodic nondestructive inspection can be valuable in characterizing corrosion and can be used in evaluating the effectiveness of chemical treatments used to control or reduce corrosion. Presently, they are investigating the feasibility and practicality of using ultrasound in routing testing for gap measurement, for evaluating the corrosion and assessing the degree of denting. The tube/support structure can be modeled as a multilayer, reverberant target, which when tested with ultrasound results in two sets of reverberating echoes [1]. One set corresponds to the tube wall and the other to the support plate. These echoes must be decomposed and identified in order to evaluate the tube/support structure. This report presents experimental results along with a discussion of various measurements and processing techniques for decomposing and interpreting tube/support echoes at different stages of corrosion

  2. Production of hydrogen from methanol over Cu/ZnO catalysts promoted by ZrO2 and Al2O3

    NARCIS (Netherlands)

    Navarro, R.M.; Melián-Cabrera, I.; Boutonnet, M.; Birgersson, H.; Agrell, J.; Fierro, J.L.G.

    2003-01-01

    Production of H2 from methanol by steam reforming, partial oxidation, or a combination thereof was studied over Cu/ZnO-based catalysts. The catalysts were characterized by a variety of techniques, including N2O chemisorption, X-ray photoelectron spectroscopy, X-ray diffraction, and

  3. Specification of steam generator, condenser and regenerative heat exchanger materials for nuclear applications

    International Nuclear Information System (INIS)

    Jovasevic, J.V.; Stefanovic, V.M.; Spasic, Z.LJ.

    1977-01-01

    The basic standards specifications of materials for nuclear applications are selected. Seamless Ni-Cr-Fe alloy Tubes (Inconel-600) for steam generators, condensers and other heat exchangers can be employed instead of austenitic stainless steal or copper alloys tubes; supplementary requirements for these materials are given. Specifications of Ni-Cr-Fe alloy plate, sheet and strip for steam generator lower sub-assembly, U-bend seamless copper-alloy tubes for heat exchanger and condensers are also presented. At the end, steam generator channel head material is proposed in the specification for carbon-steel castings suitable for welding

  4. Purifier-integrated methanol reformer for fuel cell vehicles

    Science.gov (United States)

    Han, Jaesung; Kim, Il-soo; Choi, Keun-Sup

    We developed a compact, 3-kW, purifier-integrated modular reformer which becomes the building block of full-scale 30-kW or 50-kW methanol fuel processors for fuel cell vehicles. Our proprietary technologies regarding hydrogen purification by composite metal membrane and catalytic combustion by washcoated wire-mesh catalyst were combined with the conventional methanol steam-reforming technology, resulting in higher conversion, excellent quality of product hydrogen, and better thermal efficiency than any other systems using preferential oxidation. In this system, steam reforming, hydrogen purification, and catalytic combustion all take place in a single reactor so that the whole system is compact and easy to operate. Hydrogen from the module is ultrahigh pure (99.9999% or better), hence there is no power degradation of PEMFC stack due to contamination by CO. Also, since only pure hydrogen is supplied to the anode of the PEMFC stack, 100% hydrogen utilization is possible in the stack. The module produces 2.3 Nm 3/h of hydrogen, which is equivalent to 3 kW when PEMFC has 43% efficiency. Thermal efficiency (HHV of product H 2/HHV of MeOH in) of the module is 89% and the power density of the module is 0.77 kW/l. This work was conducted in cooperation with Hyundai Motor Company in the form of a Korean national project. Currently the module is under test with an actual fuel cell stack in order to verify its performance. Sooner or later a full-scale 30-kW system will be constructed by connecting these modules in series and parallel and will serve as the fuel processor for the Korean first fuel cell hybrid vehicle.

  5. A concept of PWR using plate and shell heat exchangers

    International Nuclear Information System (INIS)

    Freire, Luciano Ondir; Andrade, Delvonei Alves de

    2015-01-01

    In previous work it was verified the physical possibility of using plate and shell heat exchangers for steam generation in a PWR for merchant ships. This work studies the possibility of using GESMEX commercial of the shelf plate and shell heat exchanger of series XPS. It was found it is feasible for this type of heat exchanger to meet operational and accidental requirements for steam generation in PWR. Additionally, it is proposed an arrangement of such heat exchangers inside the reactor pressure vessel. Such arrangement may avoid ANSI/ANS51.1 nuclear class I requirements on those heat exchangers because they are contained in the reactor coolant pressure barrier and play no role in accidental scenarios. Additionally, those plates work under compression, preventing the risk of rupture. Being considered non-nuclear safety, having a modular architecture and working under compression may turn such architectural choice a must to meet safety objectives with improved economics. (author)

  6. A concept of PWR using plate and shell heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Luciano Ondir; Andrade, Delvonei Alves de, E-mail: luciano.ondir@gmail.com, E-mail: delvonei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    In previous work it was verified the physical possibility of using plate and shell heat exchangers for steam generation in a PWR for merchant ships. This work studies the possibility of using GESMEX commercial of the shelf plate and shell heat exchanger of series XPS. It was found it is feasible for this type of heat exchanger to meet operational and accidental requirements for steam generation in PWR. Additionally, it is proposed an arrangement of such heat exchangers inside the reactor pressure vessel. Such arrangement may avoid ANSI/ANS51.1 nuclear class I requirements on those heat exchangers because they are contained in the reactor coolant pressure barrier and play no role in accidental scenarios. Additionally, those plates work under compression, preventing the risk of rupture. Being considered non-nuclear safety, having a modular architecture and working under compression may turn such architectural choice a must to meet safety objectives with improved economics. (author)

  7. Evaluation of EDTA based chemical formulations for the cleaning of monel-400 tubed steam generators

    International Nuclear Information System (INIS)

    Velmurugan, S.; Rufus, A.L.; Sathyaseelan, V.S.; Kumar, P.S.; Veena, S.N.; Srinivasan, M.P.; Narasimhan, S.V.

    1998-01-01

    The Steam Generator (SG) is an important component in any nuclear power plant which contributes significantly for the over all performance of the reactor. The failure of SG tubes occurs mainly by corrosion under accelerated conditions caused by fouling. There is continuous ingress of the corrosion products and ionic impurities from the condenser and feed train of the secondary heat transfer system. The corrosion products accumulate in the stagnant areas near the tube sheet, over the tube support plates and in the tube to tube support plate crevices. These accumulated deposits help to concentrate the aggressive impurities and induce a variety of corrosion processes affecting the structural materials and finally leading to failure of the SG tube. Scale forming impurities can deposit over the tube surfaces and result in reduction of heat transfer efficiency and over heating of the surfaces. Every effort is being made to control the transport of impurities to the steam generator. Increased blow down, installation of condensate polishers and use of all volatile amines have helped to reduce the corrosion product and ionic impurities input into the steam generators of PHWRs. Despite these efforts, failures of SG tubes in PHWRs have been reported. Hence, attempts are being made to develop chemical formulations to clean the deposits accumulated in the steam generators. The EPRI-SGOG chemical cleaning process has been tried with good success in steam generators of different designs including the steam generators of PHWRs. This paper discusses the work on the evaluation of EDTA based chemical cleaning formulations for monel-400 tubed steam generators of PHWRs. (author)

  8. Two-Phase Instability Characteristics of Printed Circuit Steam Generator for the Low Pressure Condition

    International Nuclear Information System (INIS)

    Kang, Han-Ok; Han, Hun Sik; Kim, Young-In; Kim, Keung Koo

    2015-01-01

    Reduction of installation space for steam generators can lead to much smaller reactor vessel with resultant decrease of overall manufacturing cost for the components. A PCHE(Printed Circuit Heat Exchanger) is one of the compact types of heat exchangers available as an alternative to conventional shell and tube heat exchangers. Its name is derived from the procedure used to manufacture the flat metal plates that form the core of the heat exchanger, which is done by chemical milling. These plates are then stacked and diffusion bonded, converting the plates into a solid metal block containing precisely engineered fluid flow passages. PCSG(Printed Circuit Steam Generator) is a potential candidate to be applied to the integral reactor with its compactness and mechanical robustness. For the introduction of new steam generator, design requirement for the two-phase flow instability should be considered. This paper describes two-phase flow instability characteristics of PCSG for the low pressure condition. PCSG is a potential candidate to be applied to the integral reactor with its compactness and mechanical robustness. Interconnecting flow path was developed to mitigate the two-phase flow instability in the cold side. The flow characteristics of two-phase flow instability at the PCSG is examined experimentally in this study

  9. Leakage experiences with 1 MW steam generator

    International Nuclear Information System (INIS)

    Kanamori, A.; Kawara, M.; Sano, A.

    1975-01-01

    An 1 MW steam generator was tested from October, 1971 and completed with the first series of experiments by May, 1972 after 3600 hours of operation. During these tests, unextraordinary heat absorption was experienced in the downcomer region, which led to shortage of heat transfer area to attain the rated steam temperature and to one of the reasons of flow instabilities. The steam generator was disassembled to get test pieces for structure as well as material examinations and then it was reassembled to proceed the second series of tests. Before it was done, a modification was provided to insulate the downcomer region by putting a gas space around the downcomer tube. The gas space was provided by a dual tube and spacers were welded on the inner tube and an end plate was welded on upper parts between the two to seal the gap by means of fillet welding. After the modified steam generator was put into operation, water happened to leak into a sodium side two times through these additional welding spots for the gas insulation. This paper presents operating conditions and behaviors of monitors at the time of the leakages, identifications of leaked spots, an evaluation of causes and a treatment or a precaution for them

  10. How safe is defect specific maintenance of steam generator tubes?

    International Nuclear Information System (INIS)

    Dvorsek, T.; Cizelj, L.

    1995-01-01

    Outside diameter stress corrosion cracking at the tube to tube support plate intersections is assessed in the paper. The impact of defect specific maintenance on steam generator operation safety and reliability was investigated. This was performed by comparing efficiencies of defect specific and traditional maintenance strategy. The efficiency was studied through expected primary-to-secondary leak rate and tube rupture probability in a case of postulated accidental operating conditions, and number of tubes which shall be plugged using both maintenance strategies. In general, the efficiency of specific maintenance is function of particular steam generator and operating cycle. (author)

  11. Analgesic Effect of Methanol Leaf Extract of Alstonia Boonei De Wild ...

    African Journals Online (AJOL)

    pain and other conditions. Methods: Alstonia boonei leaves were extracted with methanol. Rodent models were employed in screening the analgesic effect of the extract. Pain indices evaluated in hot plate and tail flick tests, formalin pain test and mouse writhing assay were mean reaction time to latent heat, time spent in ...

  12. Response of a direct methanol fuel cell to fuel change

    Energy Technology Data Exchange (ETDEWEB)

    Leo, T.J. [Dpto de Sistemas Oceanicos y Navales- ETSI Navales, Univ. Politecnica de Madrid, Avda Arco de la Victoria s/n, 28040 Madrid (Spain); Raso, M.A.; de la Blanca, E. Sanchez [Dpto de Quimica Fisica I- Fac. CC. Quimicas, Univ. Complutense de Madrid, Avda Complutense s/n, 28040 Madrid (Spain); Navarro, E.; Villanueva, M. [Dpto de Motopropulsion y Termofluidodinamica, ETSI Aeronauticos, Univ. Politecnica de Madrid, Pza Cardenal Cisneros 3, 28040 Madrid (Spain); Moreno, B. [Instituto de Ceramica y Vidrio, Consejo Superior de Investigaciones Cientificas, C/Kelsen 5, Campus de la UAM, 28049 Cantoblanco, Madrid (Spain)

    2010-10-15

    Methanol and ethanol have recently received much attention as liquid fuels particularly as alternative 'energy-vectors' for the future. In this sense, to find a direct alcohol fuel cell that able to interchange the fuel without losing performances in an appreciable way would represent an evident advantage in the field of portable applications. In this work, the response of a in-house direct methanol fuel cell (DMFC) to the change of fuel from methanol to ethanol and its behaviour at different ambient temperature values have been investigated. A corrosion study on materials suitable to fabricate the bipolar plates has been carried out and either 316- or 2205-duplex stainless steels have proved to be adequate for using in direct alcohol fuel cells. Polarization curves have been measured at different ambient temperature values, controlled by an experimental setup devised for this purpose. Data have been fitted to a model taking into account the temperature effect. For both fuels, methanol and ethanol, a linear dependence of adjustable parameters with temperature is obtained. Fuel cell performance comparison in terms of open circuit voltage, kinetic and resistance is established. (author)

  13. Process for obtaining methanol. Verfahren zur Gewinnung von Methanol

    Energy Technology Data Exchange (ETDEWEB)

    Link, H; Watson, A

    1983-12-08

    Synthetic gas is generated and converted to methanol in a reactor. After the separation of the crude methanol, there is a multi-stage methanol distillation. Condensate occurring during distillation is at least partly fed back before the methanol synthesis.

  14. Structural analysis of steam generator internals following feed water main steam line break: DLF approach

    International Nuclear Information System (INIS)

    Bhasin, Vivek; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

    1993-01-01

    In order to evaluate the possible release of radioactivity in extreme events, some postulated accidents are analysed and studied during the design stage of Steam Generator (SG). Among the various accidents postulated, the most important are Feed Water Line Break (FWLB) and Main Steam Line Break (MSLB). This report concerns with dynamic structural analysis of SG internals following FWLB/MSLB. The pressure/drag-force time histories considered were corresponding to the conditions leading to the accident of maximum potential. The SG internals were analysed using two approaches of structural dynamics. In first approach simplified DLF method was adopted. This method yields an upper bound values of stresses and deflection. In the second approach time history analysis by Mode Superposition Technique was adopted. This approach gives more realistic results. The structure was qualified as per ASME B and PV Code SecIII NB. It was concluded that in all the components except perforated flow distribution plate, the stress values based on elastic analysis are within the limits specified by ASME Code. In case of perforated flow distribution plate during the MSLB transient the stress values based on elastic analysis are higher than the ASME Code limits. Therefore, its limit load analysis had to be done. Finally, the collapse pressure evaluated using limit load analysis was shown to be within the limits of ASME B and PV Code SecIII Nb. (author). 31 refs., 94 figs., 16 tabs

  15. Televisual inspection of cleanliness in secondary side of steam generator

    International Nuclear Information System (INIS)

    Zhou Shoukang; Ding Xunshen

    1995-01-01

    For U-type tube steam generator (UTSG), the deposit will be piled on the low velocity area of tubesheet, tube bundle and support plates during operation. The deposit is the hidden region of pollutant, and the concentration effect will create the corrosion situation in secondary side of steam generator. So, it is very necessary to inspect the cleanliness of SG. The paper introduces the technique of cleanliness inspection with the VP3 1TV apparatus. The steam generator cleanliness inspection of GNP unit 1 and 2, after installation, major transients and commercial operation, shows that the 1TV technique not only provides the cleanliness condition of tubesheet, and removes the loose foreign object, but also provides the basis for the determination of lancing procedure, confirms the result of lancing, and gets the cleanliness conclusion according to the appropriate qualified standard

  16. Steam Generator Group Project: Task 10, Secondary side examination

    International Nuclear Information System (INIS)

    Schwenk, E.B.

    1987-06-01

    This report concludes an effort to examine and assess from the secondary side, the condition of the retired-from-service Surry 2A steam generator. It is includes photographs of degradation of various components or regions in a generic recirculating type steam generator. The photographic detail given in the text (and the previous report NUREG/CR-3843, PNL-5033) have not been readily available to many investigators outside the Nuclear Steam Supply Vendors and Users. The photographs include views of Inconel 600 heat exchanger tubes (0.875 diameter [nominal] x 0.050 inch wall) showing deformed and intergranularly stress-corrosion cracked U-bends, tube denting in the support plate, intergranular attack and thinning (both in the tube sheet region), support plat deformation and cracking at flow slots and in ligaments between flow holes and tube holes. In addition, photographs of tube pitting, anti-vibration bar fretting, and the sludge pile are presented. An experimental stress analysis was conducted on a distorted Row 1 tube in the region of a compressed flow slot between the 6th and 7th (top) support plates. During removal of the tube, relaxation strains were measured and residual stresses calculated. Finally a cursory metallurgical failure analysis was conducted on a broken U-bend (R1C91) to determine its mode of failure. A rotabroach boring technique was used to make multiple penetrations with minimal damage to the secondary side, at various locations on the shell

  17. Indication chamber of liquid metal fired steam generators with double wall for heat transfer

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1982-01-01

    The double wall of the steam generator consists of inner and outer tubes anchored in a tube plate. Between the tubes are indication spaces which end in recesses formed at least in one of the tube plates and coaxial with the outer tubes. The recesses interconnected with channels form the indication chamber to which is connected at least one sensor of the alarm signal equipment. (B.S.)

  18. Steam 80 steam generator instrumentation

    International Nuclear Information System (INIS)

    Carson, W.H.; Harris, H.H.

    1980-01-01

    This paper describes two special instrumentation packages in an integral economizer (preheater) steam generator of one of the first System 80 plants scheduled to go into commercial operation. The purpose of the instrumentation is to obtain accurate operating information from regions of the secondary side of the steam generator inaccessible to normal plant instrumentation. In addition to verification of the System 80 steam generator design predictions, the data obtained will assist in verification of steam generator thermal/hydraulic computer codes developed for generic use in the industry

  19. Methanol fuel processor and PEM fuel cell modeling for mobile application

    Energy Technology Data Exchange (ETDEWEB)

    Chrenko, Daniela [ISAT, University of Burgundy, Rue Mlle Bourgoise, 58000 Nevers (France); Gao, Fei; Blunier, Benjamin; Bouquain, David; Miraoui, Abdellatif [Transport and Systems Laboratory (SeT) - EA 3317/UTBM, Fuel cell Laboratory (FCLAB), University of Technology of Belfort-Montbeliard, Rue Thierry Mieg 90010, Belfort Cedex (France)

    2010-07-15

    The use of hydrocarbon fed fuel cell systems including a fuel processor can be an entry market for this emerging technology avoiding the problem of hydrogen infrastructure. This article presents a 1 kW low temperature PEM fuel cell system with fuel processor, the system is fueled by a mixture of methanol and water that is converted into hydrogen rich gas using a steam reformer. A complete system model including a fluidic fuel processor model containing evaporation, steam reformer, hydrogen filter, combustion, as well as a multi-domain fuel cell model is introduced. Experiments are performed with an IDATECH FCS1200 trademark fuel cell system. The results of modeling and experimentation show good results, namely with regard to fuel cell current and voltage as well as hydrogen production and pressure. The system is auto sufficient and shows an efficiency of 25.12%. The presented work is a step towards a complete system model, needed to develop a well adapted system control assuring optimized system efficiency. (author)

  20. Formaldehyde, methanol and hydrocarbon emissions from methanol-fueled cars

    International Nuclear Information System (INIS)

    Williams, R.L.; Lipari, F.; Potter, R.A.

    1990-01-01

    Exhaust and evaporative emissions tests were conducted on several methanol- and gasoline-fueled vehicles. Separate samples for chromatographic analysis of formaldehyde, methanol, and individual hydrocarbons were collected in each of the three phases of the driving cycle and in each of the two portions of the evaporative emissions test. One vehicle, equipped with an experimental variable-fuel engine, was tested using methanol/gasoline fuel mixtures of 100, 85, 50, 15, and 0 percent methanol. Combustion-generated hydrocarbons were lowest using methanol fuel, and increased several-fold as the gasoline fraction was increased. Gasoline components in the exhaust increased from zero as the gasoline fraction of the fuel was increased. On the other hand, formaldehyde emissions were several times higher using methanol fuel than they were using gasoline. A dedicated methanol car and the variable-fuel car gave similar emissions patterns when they both were tested using methanol fuel. The organic-carbon composition of the exhaust was 85-90 percent methanol, 5-7 percent formaldehyde, and 3-9 percent hydrocarbons. Several cars that were tested using gasoline emitted similar distributions of hydrocarbons, even through the vehicles represented a broad range of current and developmental engine families and emissions control systems

  1. Techno-economic assessment of integrating methanol or Fischer-Tropsch synthesis in a South African sugar mill.

    Science.gov (United States)

    Petersen, Abdul M; Farzad, Somayeh; Görgens, Johann F

    2015-05-01

    This study considered an average-sized sugar mill in South Africa that crushes 300 wet tonnes per hour of cane, as a host for integrating methanol and Fischer-Tropsch synthesis, through gasification of a combined flow of sugarcane trash and bagasse. Initially, it was shown that the conversion of biomass to syngas is preferably done by catalytic allothermal gasification instead of catalytic autothermal gasification. Thereafter, conventional and advanced synthesis routes for both Methanol and Fischer-Tropsch products were simulated with Aspen Plus® software and compared by technical and economic feasibility. Advanced FT synthesis satisfied the overall energy demands, but was not economically viable for a private investment. Advanced methanol synthesis is also not viable for private investment since the internal rate of return was 21.1%, because it could not provide the steam that the sugar mill required. The conventional synthesis routes had less viability than the corresponding advanced synthesis routes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Procedure and device for extracting the end of a tube inserted into a hole in a tube plate

    International Nuclear Information System (INIS)

    1980-01-01

    When constructing heat exchangers and steam generators, particularly in the construction of steam generators for nuclear power stations, many small diameter tubes have to be secured into a very thick tube plate for instance 600 mm thick. This crimping or expanding of the tube is generally performed by rolling the internal surface of the tube inside a hole drilled right through the tube plate and slightly greater in diameter than the external diameter of the tube before the tube is rolled. To check the tubes for defects, it is necessary to extract certain tubes from the tube plate in order to move the tube to a testing and inspection point and examine the part of it that was secured in the plate hole. The invention concerns the uncrimping of these tubes [fr

  3. SCDAP/RELAP5 lower core plate model

    International Nuclear Information System (INIS)

    Coryell, E.W.; Griffin, F.P.

    1999-01-01

    The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. This report describes the justification, theory, implementation, and testing of a new modeling capability which will refine the analysis of the movement of molten material from the core region to the vessel lower head. As molten material moves from the core region through the core support structures it may encounter conditions which will cause it to freeze in the region of the lower core plate, delaying its arrival to the vessel head. The timing of this arrival is significant to reactor safety, because during the time span for material relocation to the lower head, the core may be experiencing steam-limited oxidation. The time at which hot material arrives in a coolant-filled lower vessel head, thereby significantly increasing the steam flow rate through the core region, becomes significant to the progression and timing of a severe accident. This report is a revision of a report INEEL/EXT-00707, entitled ''Preliminary Design Report for SCDAP/RELAP5 Lower Core Plate Model''

  4. Ash particle erosion on steam boiler convective section

    Energy Technology Data Exchange (ETDEWEB)

    Meuronen, V

    1998-12-31

    In this study, equations for the calculation of erosion wear caused by ash particles on convective heat exchanger tubes of steam boilers are presented. A new, three-dimensional test arrangement was used in the testing of the erosion wear of convective heat exchanger tubes of steam boilers. When using the sleeve-method, three different tube materials and three tube constructions could be tested. New results were obtained from the analyses. The main mechanisms of erosion wear phenomena and erosion wear as a function of collision conditions and material properties have been studied. Properties of fossil fuels have also been presented. When burning solid fuels, such as pulverized coal and peat in steam boilers, most of the ash is entrained by the flue gas in the furnace. In bubbling and circulating fluidized bed boilers, particle concentration in the flue gas is high because of bed material entrained in the flue gas. Hard particles, such as sharp edged quartz crystals, cause erosion wear when colliding on convective heat exchanger tubes and on the rear wall of the steam boiler. The most important ways to reduce erosion wear in steam boilers is to keep the velocity of the flue gas moderate and prevent channelling of the ash flow in a certain part of the cross section of the flue gas channel, especially near the back wall. One can do this by constructing the boiler with the following components. Screen plates can be used to make the velocity and ash flow distributions more even at the cross-section of the channel. Shield plates and plate type constructions in superheaters can also be used. Erosion testing was conducted with three types of tube constructions: a one tube row, an in- line tube bank with six tube rows, and a staggered tube bark with six tube rows. Three flow velocities and two particle concentrations were used in the tests, which were carried out at room temperature. Three particle materials were used: quartz, coal ash and peat ash particles. Mass loss

  5. Testing improved steam separators in third energy block of Chernobyl AES

    Energy Technology Data Exchange (ETDEWEB)

    Novosel' skiy, O Yu; Karasev, V B; Sakovich, E V; Lyutov, M A; An' kov, V I

    1984-12-01

    Improved steam separating drums are described. These have a four-row arrangement of the pipe unions of the steam-water supply lines, with increased diameter. Two collectors 400 mm in diameter from adjacent separators drums go to a single steam line 600 mm in diameter, which goes to the turbine. Tests of the system were conducted at a pressure of 7 MPa and at thermal power of 65, 83, 93, and 100% of rated value to determine the dependence of the moisture content at the output from the separator drum on the mass level at constant thermal power of the block. The separator drums, 2600 mm in diameter, were found to have a reserve for maximum permissible moisture content, and the moisture content of the steam in the central pipe unions did not exceed 0.02% with a level in the drums 200 mm above the rated level. Thus maintenance of the level above the submerged perforated plate by 100 mm above the planned level permits an increase of the water reserve in the multiple forced circulation circuit by 28 m/sup 3/ and does not hinder an increase of the steam productivity of the block.

  6. Model tests of a once-through steam generator for land-blocker assessment and THEDA code verification. Final report

    International Nuclear Information System (INIS)

    Carter, H.R.; Childerson, M.T.; Moskal, T.E.

    1983-06-01

    The Babcock and Wilcox Company (B and W) operating Once-Through Steam Generators (OTSGs) have experienced leaking tubes in a region adjacent to the untubed inspection lane. The tube leaks have been attributed to an environmentally-assisted fatigue mechanism with moisture transported up the inspection lane being a major factor in the tube-failure process. B and W has developed a hardware modification (lane blockers) to mitigate the detrimental effects of inspection lane moisture. A 30-tube Laboratory Once-through Steam Generator (Designated OTSGC) was designed, fabricated, and tested. Tests were performed with and without five flat-plate lane blockers installed on tube-support plates (TSPs) 10, 11, 12, 13, and 14. The test results were utilized to determine the effectiveness of lane blockers for eliminating moisture transport to the upper tubesheet in the inspection lanes and to benchmark the predictive capabilities of a three-dimensional steam-generator computer code, THEDA

  7. Steam generator of FBR type reactor

    International Nuclear Information System (INIS)

    Hashiguchi, Ko.

    1992-01-01

    Liquid metal (for example, mercury) which is scarcely reactive with metal sodium is contained and cover gases which are scarcely reactive with the liquid metal are filled in a steam generator of an FBR type reactor and it is closed. The heat of primary sodium is transferred to the liquid metal, which is not reactive with sodium, in a primary thermal conduction portion. Since the temperature of the primary thermal conduction portion is high, the density is extremely low. On the other hand, since a second thermal conduction portion is kept at a single phase and the temperature is lower compared with that of the first thermal conduction portion, the density is kept high. since the density difference and gas jetting speed generate a great circulating force to liquid metal passing the opening of a partition plate, heat can be conducted on the side of water without disposing pumps. The steam concentration in the liquid metal is low being in a single phase of steams, corrosion caused from the outside of pipes of the primary thermal conduction pipe is scarcely promoted. Even if sodium leaks should be caused, since the sodium concentration in the liquid metal is extremely low and the reactivity is low, the temperature of the liquid metal is not elevated. (N.H.)

  8. Evaluation and Demonstration of a Mobile Steam Applicator to Disinfest Soil in Field-grown California Strawberry and Flower Production

    Science.gov (United States)

    Steam can effectively kill soil borne pests if soil temperatures can be raised to 70 °C for 20 min. The Ferrari Sterilter is capable of generating super heated steam to reach these temperatures within 5 to 7 min. Frontal plates on the machine allow it to thoroughly heat the soil to 30 cm depth, gran...

  9. Surry steam generator - examination and evaluation

    International Nuclear Information System (INIS)

    Clark, R.A.; Doctor, P.G.; Ferris, R.H.

    1985-10-01

    This report summarizes research conducted during the fourth year of the five year Steam Generator Group Project. During this period the project conducted numerous nondestructive examination (NDE) round robin inspections of the original Surry 2A steam generator. They included data acquisition/analysis and analysis-only round robins using multifrequency bobbin coil eddy current tests. In addition, the generator was nondestructively examined by alternate or advanced techniques including ultrasonics, optical fiber, profilometry and special eddy current instrumentation. The round robin interpretation data were compared. To validate the NDE results and for tube integrity testing, a selection of tubing samples, determined to be representative of the generator, was designated for removal. Initial sample removals from the generator included three sections of tube sheet, two sections of support plate and encompassed tubes, and a number of straight and U-bend tubing sections. Metallographic examination of these sections was initiated. Details of significant results are presented in the following paper. 13 figs

  10. Surry steam generator - examination and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Clark, R A; Doctor, P G; Ferris, R H

    1987-01-01

    This report summarizes research conducted during the fourth year of the five year Steam Generator Group Project. During this period the project conducted numerous nondestructive examination (NDE) round robin inspections of the original Surry 2A steam generator. They included data acquisition/analysis and analysis-only round robins using multifrequency bobbin coil eddy current tests. In addition, the generator was nondestructively examined by alternate or advanced techniques including ultrasonics, optical fiber, profilometry and special eddy current instrumentation. The round robin interpretation data were compared. To validate the NDE results and for tube integrity testing, a selection of tubing samples, determined to be representative of the generator, was designated for removal. Initial sample removals from the generator included three sections of tube sheet, two sections of support plate and encompassed tubes, and a number of straight and U-bend tubing sections. Metallographic examination of these sections was initiated. Details of significant results are presented in the following paper.

  11. An Isothermal Steam Expander for an Industrial Steam Supplying System

    Directory of Open Access Journals (Sweden)

    Chen-Kuang Lin

    2015-01-01

    Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

  12. Mild oxidation of methane to methanol or acetic acid on supported isolated rhodium catalysts

    Science.gov (United States)

    Shan, Junjun; Li, Mengwei; Allard, Lawrence F.; Lee, Sungsik; Flytzani-Stephanopoulos, Maria

    2017-11-01

    An efficient and direct method of catalytic conversion of methane to liquid methanol and other oxygenates would be of considerable practical value. However, it remains an unsolved problem in catalysis, as typically it involves expensive or corrosive oxidants or reaction media that are not amenable to commercialization. Although methane can be directly converted to methanol using molecular oxygen under mild conditions in the gas phase, the process is either stoichiometric (and therefore requires a water extraction step) or is too slow and low-yielding to be practical. Methane could, in principle, also be transformed through direct oxidative carbonylation to acetic acid, which is commercially obtained through methane steam reforming, methanol synthesis, and subsequent methanol carbonylation on homogeneous catalysts. However, an effective catalyst for the direct carbonylation of methane to acetic acid, which might enable the economical small-scale utilization of natural gas that is currently flared or stranded, has not yet been reported. Here we show that mononuclear rhodium species, anchored on a zeolite or titanium dioxide support suspended in aqueous solution, catalyse the direct conversion of methane to methanol and acetic acid, using oxygen and carbon monoxide under mild conditions. We find that the two products form through independent pathways, which allows us to tune the conversion: three-hour-long batch-reactor tests conducted at 150 degrees Celsius, using either the zeolite-supported or the titanium-dioxide-supported catalyst, yield around 22,000 micromoles of acetic acid per gram of catalyst, or around 230 micromoles of methanol per gram of catalyst, respectively, with selectivities of 60-100 per cent. We anticipate that these unusually high activities, despite still being too low for commercial application, may guide the development of optimized catalysts and practical processes for the direct conversion of methane to methanol, acetic acid and other useful

  13. Methanol Oxidation on Pt3Sn(111) for Direct Methanol Fuel Cells: Methanol Decomposition.

    Science.gov (United States)

    Lu, Xiaoqing; Deng, Zhigang; Guo, Chen; Wang, Weili; Wei, Shuxian; Ng, Siu-Pang; Chen, Xiangfeng; Ding, Ning; Guo, Wenyue; Wu, Chi-Man Lawrence

    2016-05-18

    PtSn alloy, which is a potential material for use in direct methanol fuel cells, can efficiently promote methanol oxidation and alleviate the CO poisoning problem. Herein, methanol decomposition on Pt3Sn(111) was systematically investigated using periodic density functional theory and microkinetic modeling. The geometries and energies of all of the involved species were analyzed, and the decomposition network was mapped out to elaborate the reaction mechanisms. Our results indicated that methanol and formaldehyde were weakly adsorbed, and the other derivatives (CHxOHy, x = 1-3, y = 0-1) were strongly adsorbed and preferred decomposition rather than desorption on Pt3Sn(111). The competitive methanol decomposition started with the initial O-H bond scission followed by successive C-H bond scissions, (i.e., CH3OH → CH3O → CH2O → CHO → CO). The Brønsted-Evans-Polanyi relations and energy barrier decomposition analyses identified the C-H and O-H bond scissions as being more competitive than the C-O bond scission. Microkinetic modeling confirmed that the vast majority of the intermediates and products from methanol decomposition would escape from the Pt3Sn(111) surface at a relatively low temperature, and the coverage of the CO residue decreased with an increase in the temperature and decrease in partial methanol pressure.

  14. Prediction of localized flow velocities and turbulence in a PWR steam generator: Final report

    International Nuclear Information System (INIS)

    Stuhmiller, J.H.

    1988-05-01

    The Steam Generator Project Office (SGPO) of the Steam Generator Owners Group and Electric Power Research Institute has developed a methodology for prediction of steam generator tube buffeting and associated material wear. Turbulent buffeting of steam generator tubes causes low amplitude vibratory response which results in fretting wear at support locations. Concerns raised at the Zion Nuclear Power Plant regarding the useful life of their steam generators prompted this study, in which the SGPO methodology is applied to analysis of the Westinghouse Model 51 steam generator. The specific intent of this project was to calculate turbulent buffeting forces within the tube bank of an operating Model 51 steam generator as a first step in the overall SGPO tube vibration and wear prediction strategy. Attention is focused on flow in the vicinity of anti-vibration bars (U-bend region) and on the flow that leaves the downcomer to impact against peripheral tubes. Other projects utilized the buffeting forces calculated here to determine tube vibratory response, tube-support plate impact statistics, and material wear rates. Besides successfully calculating hydraulic buffeting loads within the tube bank, the present project has enhanced the SGPO methodology and has identified hitherto unnoticed flow phenomena that occur in the steam generator. Experiments have also been carried out to validate numerical computations of the steam generator flow field

  15. Equipment for secondary water distribution in heat exchanger, especially saturated steam generator for nuclear power plants and heat plants

    Energy Technology Data Exchange (ETDEWEB)

    Riman, J; Manek, O; Rybnicek, J

    1979-09-15

    A special structure consisting of a system of channels and a distribution plate with ports in-built above the tube-plate of a vertical-type steam generator prevents secondary water vaporization in the space above the tube-plate and thus also salt and sludge sedimentation which causes increased corrosion of heat transfer tubes. The size of the distribution plate ports is variable in the radial direction. The distribution plate is divided by means of the system of channels into at least two parts. The middle section of each part is of the through-flow type.

  16. Microbial effect of steam vacuum pasteurisation implemented after slaughtering and dressing of sheep and lamb.

    Science.gov (United States)

    Hassan, Ammar Ali; Skjerve, Eystein; Bergh, Claus; Nesbakken, Truls

    2015-01-01

    The main objective of the study was to assess the effect of steam vacuum pasteurisation on carcass contamination with focus on Escherichia coli, Enterobacteriaceae and total plate count (TPC). Additionally, the effect of an additional tryptone soy agar (TSA) step for resuscitation of Enterobacteriaceae after steam vacuum pasteurisation was investigated. Steam vacuum pasteurisation was applied at a temperature of >82°C for a duration of 10s on sheep and lamb carcasses (n=120). Samples were taken immediately: i) after trimming just before the use of steam vacuum and ii) after use of steam vacuum. Nordic Committee on Food Analysis methods were used in microbial analyses. The differences in log reduction were found significant for all of the three microorganisms (psteam vacuum pasteurisation was higher in samples where TSA+violet red bile glucose agar (VRBGA) was used compared to samples where only VRBGA was used (pSteam vacuum pasteurisation was found efficient in reducing the total count, read as TPC, as well as the level of E. coli and Enterobacteriaceae. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. A balanced strategy in managing steam generator thermal performance

    International Nuclear Information System (INIS)

    Hu, M. H.; Nelson, P. R.

    2009-01-01

    This paper presents a balanced strategy in managing thermal performance of steam generator designed to deliver rated megawatt thermal (MWt) and megawatt electric (MWe) power without loss with some amount of thermal margin. A steam generator (SG) is a boiling heat exchanger whose thermal performance may degrade because of steam pressure loss. In other words, steam pressure loss is an indicator of thermal performance degradation. Steam pressure loss is mainly a result of either 1) tube scale induced poor boiling or 2) tube plugging historically resulting from tubing corrosion, wear due to flow induced tube vibration or loose parts impact. Thermal performance degradation was historically due to tube plugging but more recently it is due to poor boiling caused by more bad than good constituents of feedwater impurities. The whole SG industry still concentrates solely on maintenance programs towards preventing causes for tube plugging and yet almost no programs on maintaining adequate boiling of fouled tubes. There can be an acceptable amount of tube scale that provides excellent boiling capacity without tubing corrosion, as operational experience has repeatedly demonstrated. Therefore, future maintenance has to come up balanced programs for allocating limited resources in both maintaining good boiling capacity and preventing tube plugging. This paper discusses also thermal performance degradation due to feedwater impurity induced blockage of tube support plate and thus subsequent water level oscillations, and how to mitigate them. This paper provides a predictive management of tube scale for maintaining adequate steam pressure and stable water level without loss in MWt/MWe or recovering from steam pressure loss or water level oscillations. This paper offers a balanced strategy in managing SG thermal performance to fulfill its mission. Such a strategy is even more important in view of the industry trend in pursuing extended power uprate as high as 20 percent

  18. Steam versus hot-water scalding in reducing bacterial loads on the skin of commercially processed poultry.

    Science.gov (United States)

    Patrick, T E; Goodwin, T L; Collins, J A; Wyche, R C; Love, B E

    1972-04-01

    A comparison of two types of scalders was conducted to determine their effectiveness in reducing bacterial contamination of poultry carcasses. A conventional hot-water scalder and a prototype model of a steam scalder were tested under commercial conditions. Total plate counts from steam-scalded birds were significantly lower than the counts of water-scalded birds immediately after scalding and again after picking. No differences in the two methods could be found after chilling. Coliform counts from steam-scalded birds were significantly lower than the counts from water-scalded birds immediately after scalding. No significant differences in coliform counts were detected when the two scald methods were compared after defeathering and chilling.

  19. End plate for e.g. solid oxide fuel cell stack, sets thermal expansion coefficient of material to predetermined value

    DEFF Research Database (Denmark)

    2011-01-01

    .05-0.3 mm. USE - End plate for solid oxide fuel cell stack (claimed). Can also be used in polymer electrolyte fuel cell stack and direct methanol fuel cell stack. ADVANTAGE - The robustness of the end plate is improved. The structure of the end plate is simplified. The risk of delamination of the stack...

  20. Handling steam generator problems: the strategy for Ringhals 3 and 4

    International Nuclear Information System (INIS)

    Larsen, G.

    1992-01-01

    An examination in Sweden of twelve Pressurized Water Reactor steam generator tubes (six from Ringhals 3 and six from Ringhals 4) revealed that several had cracks in the roll transition zone, all tubes had shallow intergranular attacks at support plate (TSP) intersections, and some from Ringhals 3 had cracks in the TSP position due to intergranular stress corrosion. It was concluded that this could drastically limit the possibility of successfully operating Ringhals 3 (which entered commercial operation in 1981) to 2010, the year when all nuclear power in Sweden will be phased out. Two possible ways to deal with the problem were investigated: replace the steam generators and uprate the plant; operate with the existing steam generators and reduce the rate of degradation by lowering the primary water temperature, with most failed tubes repaired by sleeving. The analysis showed that replacement of the Ringhals 3 steam generators would be a good investment. As there were no attacks in the TSP intersections at Ringhals 4, which started commercial operation in 1983, it was assumed possible to operate this unit until 2010 without any temperature reduction. The economic evaluation for Ringhals 4 nevertheless indicated that it would be cost effective to replace the steam generators and uprate Ringhals 4 to 112%. However, a new economic study showed that it will still be cost effective to replace the steam generators at Ringhals 3, but it is not clear that there is still a case for replacement at Ringhals 4. Ringhals 3 steam generators will be replaced in 1995, while Ringhals 4 will continue to operate with the existing steam generators. (Author)

  1. DFT Studies of Adsorption of Cu7-atom Nanoclusters on TiO2 Surfaces and Application to Methanol Steam Reforming Reactions

    Science.gov (United States)

    Taft, Michael J., Sr.

    Alcohol conversion to hydrogen, via steam reforming, is an alternative energy process that is promising for the future of clean energy economies. With advancements in fuel cell technologies, on-board hydrogen reforming could leverage already existing automotive designs and fuel infrastructure. The design of catalytic materials with tunable properties requires a level of insight that has yet to be achieved experimentally. The central objective of this project is to develop a working model of metal-oxide surface mediated copper clusters, since such catalytic beds have a wide-range of applications. More specifically, we investigate the catalytic framework of this process with theoretical models of the active metal (Cu) and metal­oxide support (TiO2). We employ a Density Functional Theory (DFT)-Generalized Gradient Approximation (GGA) approach for the quantum level electronic structure calculations of Cu, TiO2 and CH3OH. Additionally, we have generated anatase (A(001), A(101)) and rutile (R(100), R(110)) surface morphologies and 7­atom copper cluster complexes with those planes. To examine the possible influence of TiO2 on the adsorption properties of our active metal, Cu7, we have carried out adsorption studies with CH3OH. Our final data and observations predict that the Cu7 cluster adopts a symmetric pentagonal bipyramidal geometry with D5h symmetry. We find that the anatase morphology has a greater overall stability than rutile. The adsorption strength of the Cu7 cluster has been predicted in this study to be according to the following order: A(001) > A(101)> R(110). Indeed, the R(100) surface appears to be an unfavorable surface for metal cluster binding. Our data indicates that copper cluster stabilization on the metal-oxide surface depends on the nature of the crystal face. Again, we studied the adsorption properties of methanol on nascent Cu7 cluster, Cu7-TiO 2 complex and on pure TiO2-surface in A(001) polymorphic form. The calculations revealed that methanol

  2. Steam turbine cycle

    International Nuclear Information System (INIS)

    Okuzumi, Naoaki.

    1994-01-01

    In a steam turbine cycle, steams exhausted from the turbine are extracted, and they are connected to a steam sucking pipe of a steam injector, and a discharge pipe of the steam injector is connected to an inlet of a water turbine. High pressure discharge water is obtained from low pressure steams by utilizing a pressurizing performance of the steam injector and the water turbine is rotated by the high pressure water to generate electric power. This recover and reutilize discharged heat of the steam turbine effectively, thereby enabling to improve heat efficiency of the steam turbine cycle. (T.M.)

  3. Disposal and handling of nuclear steam generator chemical cleaning wastes

    International Nuclear Information System (INIS)

    Larrick, A.P.; Schneidmiller, D.

    1978-01-01

    A large number of pressurized water nuclear reactor electrical generating plants have experienced a corrosion-related problem with their steam generators known as denting. Denting is a mechanical deformation of the steam generator tubes that occurs at the tube support plates. Corrosion of the tube support plates occurs within the annuli through which the tubes pass and the resulting corrosion oxides, which are larger in volume than the original metal, compress and deform the tubes. In some cases, the induced stresses have been severe enough to cause tube and/or support cracking. The problem was so severe at the Turkey Point and Surrey plants that the tubing is being replaced. For less severe cases, chemical cleaning of the oxides, and other materials which deposit in the annuli from the water, is being considered. A Department of Energy-sponsored program was conducted by Consolidated Edison Co. of New York which identified several suitable cleaning solvents and led to in-plant chemical cleaning pilot demonstrations in the Indian Point Unit 1 steam generators. Current programs to improve the technology are being conducted by the Electric Power Research Institute, and the three PWR NSSS vendors with the assistance of numerous consultants, vendors, and laboratories. These programs are expected to result in more effective, less corrosive solvents. However, after a chemical cleaning is conducted, a large problem still remains- that of disposing of the spent wastes. The paper summarizes some of the methods currently available for handling and disposal of the wastes

  4. Steam condenser

    International Nuclear Information System (INIS)

    Masuda, Fujio

    1980-01-01

    Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)

  5. 1995 world methanol conference

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The 20 papers contained in this volume deal with the global markets for methanol, the production of MTBE, integrating methanol production into a coal-to-SNG complex, production of methanol from natural gas, catalysts for methanol production from various synthesis gases, combined cycle power plants using methanol as fuel, and economics of the methanol industry. All papers have been processed for inclusion on the data base

  6. Towards a methanol economy based on homogeneous catalysis: methanol to H2 and CO2 to methanol

    DEFF Research Database (Denmark)

    Alberico, E.; Nielsen, Martin

    2015-01-01

    The possibility to implement both the exhaustive dehydrogenation of aqueous methanol to hydrogen and CO2 and the reverse reaction, the hydrogenation of CO2 to methanol and water, may pave the way to a methanol based economy as part of a promising renewable energy system. Recently, homogeneous...

  7. Photographic inspection apparatus and process to know the shape and the dimensions of the end parts of steam generator tubes

    International Nuclear Information System (INIS)

    Martin, A.

    1986-01-01

    Before any inspection or repair operation of the tubes of a steam generator, one needs to know the shape and the dimension of the hole of the tube in the near the primary face of the tube plate. The photographic inspection apparatus is moved parallel with the tube plate, inside the water box, such as its optical axis keeps parallel to a determined direction during its displacement. One takes successively photographs of the primary face of the tube plate with the photographic apparatus in different positions, to obtain at least two photographs of each tube to be inspected, under different angles. Photographs are developed at a determined scale of the primary face of the tube plate and of the tube ends. The photographs are oriented two by two to obtain a stereophotogrammetric view of the end parts of each tube. Measurements and examinations are done from the stereophotogrammetric view obtained for each tube, outside the steam generator zone. The invention concerns the process and also the photographic apparatus described in the present patent [fr

  8. Recent Studies on Methanol Crossover in Liquid-Feed Direct Methanol Fuel Cells

    Science.gov (United States)

    Valdez, T. I.; Narayanan, S. R.

    2000-01-01

    In this work, the effects of methanol crossover and airflow rates on the cathode potential of an operating direct methanol fuel cell are explored. Techniques for quantifying methanol crossover in a fuel cell and for separating the electrical performance of each electrode in a fuel cell are discussed. The effect of methanol concentration on cathode potential has been determined to be significant. The cathode is found to be mass transfer limited when operating on low flow rate air and high concentrations of methanol. Improvements in cathode structure and operation at low methanol concentration have been shown to result in improved cell performance.

  9. Vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters

    International Nuclear Information System (INIS)

    Ahmed, Musahid; Ahmed, Musahid; Wilson, Kevin R.; Belau, Leonid; Kostko, Oleg

    2008-01-01

    In this work we report on the vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters. Clusters of methanol with water are generated via co-expansion of the gas phase constituents in a continuous supersonic jet expansion of methanol and water seeded in Ar. The resulting clusters are investigated by single photon ionization with tunable vacuum ultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry. Protonated methanol clusters of the form (CH3OH)nH + (n=1-12) dominate the mass spectrum below the ionization energy of the methanol monomer. With an increase in water concentration, small amounts of mixed clusters of the form (CH3OH)n(H2O)H + (n=2-11) are detected. The only unprotonated species observed in this work are the methanol monomer and dimer. Appearance energies are obtained from the photoionization efficiency (PIE) curves for CH3OH +, (CH 3OH)2 +, (CH3OH)nH + (n=1-9), and (CH 3OH)n(H2O)H + (n=2-9 ) as a function of photon energy. With an increase in the water content in the molecular beam, there is an enhancement of photoionization intensity for methanol dimer and protonated methanol monomer at threshold. These results are compared and contrasted to previous experimental observations

  10. Hideout of sea water impurities in steam generator tube deposits: laboratory and field studies

    International Nuclear Information System (INIS)

    Balakrishnan, P.V.; Turner, C.W.; Thompson, R.; Sawochka, S.

    1996-01-01

    Sea water impurities hide out within thin (∼10 μm) deposits on steam generator tubes, as demonstrated by both laboratory studies using segments of fouled steam generator tubes pulled in 1992 from Crystal River-3 nuclear power station and field hideout return studies performed during recent plant shutdowns. Laboratory tests performed at 279 o C (534 o F) and heat fluxes ranging from 35 to 114 kW/m 2 (11,100 - 36,150 Btu/h.ft 2 ), conditions typical of the lower tubesheet to the first support plate region of a once-through steam generator, showed that impurity hideout can occur in thin free-span tube deposits. The extent of hideout increased with increasing heat flux. Soluble species, such as sodium and chloride ions, returned promptly to the bulk water from the deposits when the heat flux was turned off, whereas less soluble species, such as calcium sulfate and magnesium hydroxide, returned more slowly. Recent field hideout return studies performed at Crystal River-3 where the water level in the steam generators was maintained below the first tube support plate during the shutdown, thus wetting only the thin deposits in the free span and the small sludge pile, corroborate the laboratory findings, showing that hideout does indeed occur in the free-span regions of the tubes. These findings suggest that hideout within tube deposits has to be accounted for in the calculation of crevice chemistry from hideout return studies and in controlling the bulk chemistry using the molar ratio criterion. (author). 3 refs., 4 tabs., 3 figs

  11. Modeling and field studies of fouling in once-through steam generators

    International Nuclear Information System (INIS)

    Thompson, R.; Gaudreau, T.

    1995-01-01

    Efforts of the past 10 years to minimize fouling of the Crystal River-3 once-through steam generators are reviewed. The major focus has been on improving at-temperature pH control in the secondary cycle. Various concentrations of different pH control agents were tested in the field for hundreds of days to determine their effect on steam generator fouling. High concentrations of morpholine (50--100 ppm) in the feedwater were found to apparently produce de-fouling of the steam generators without an associated decrease in feedwater iron concentration as compared to that at lower levels of morpholine. Computer modeling of the pH(t) within the OTSG for the various chemistries tested indicates that the pH can change significantly with elevation within the steam generator by varying the pH control agent or its concentration. It is postulated that these variations in pH may change the surface charge of the tubes, tube support plates, and/or corrosion product particles in solution, to favor either deposition or repulsion of the particles, and thereby producing conditions that either favor fouling or de-fouling of the OTSG. Crystal River-3 experience indicates that corrosion product deposition and release processes inside the steam generator can be chemically manipulated to favor release, and thereby maximize plant performance, and delay or avoid costly hydraulic or chemical cleanings

  12. An Improved Steam Injection Model with the Consideration of Steam Override

    OpenAIRE

    He , Congge; Mu , Longxin; Fan , Zifei; Xu , Anzhu; Zeng , Baoquan; Ji , Zhongyuan; Han , Haishui

    2017-01-01

    International audience; The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, th...

  13. Chemical preventive remedies for steam generators fouling and tube support plate blockages

    International Nuclear Information System (INIS)

    Alves Vieira, M.; Mayos, M.; Coquio, N.; Fourcroy, H.; Battesti, P.

    2010-01-01

    In 2006, EDF identified on several PWR units broached hole blockage on the upper Steam Generator (SG) Tube Support Plates (TSP). TSP blockage often occurs in association with secondary fouling. The units with copper alloys materials are more affected due the applied low pH 25 o C (9.20) all volatile treatment (AVT). Carbon steels materials are less protected against flow accelerated corrosion (FAC) and therefore more corrosion products enter the SGs through the final feed water (FFW). In parallel of chemical cleanings to remove oxides deposits in SGs, EDF has defined a strategy to improve operating conditions. It mainly relies on the removal of copper alloys materials to implement a high pH AVT (9.60) as a preventive remedy. However for some plants, copper alloys removal is not straightforward due to environmental constraints. EDF must indeed manage the implementation of a biocide treatment needed in closed loop cooling systems (as copper has a bacteriostatic effect on micro-organisms) and more generally must comply with discharge authorisations for chemical conditioning reagents or biocide reagent. An alternative conditioning was tested on the Dampierre 4 unit in 2007/2008 during 6 months to assess if operating at 9.40 was acceptable regarding the impacts on copper alloys materials. The perspective would be to implement it in the units where no biocide treatment can be applied on a short term. In parallel, other chemical conditionings or additives will be implemented or tested. First of all, EDF will carry out a trial test with APA in order to assess its efficiency on the removal of oxides deposits through SG blowdown. On the other hand, AVT with high pH ethanolamine (ETA) will be implemented as an alternative of ammonia and morpholine conditioning on some chosen plants. Ethanolamine is selected as a way to mitigate FAC kinetics in two-phase flow areas (reheaters or moisture heater separator) or to limit liquid releases. This paper provides the lessons of the

  14. The (p, ρ, T) of (methanol + benzene) and (methanol + ethylbenzene)

    International Nuclear Information System (INIS)

    Naziev, Yashar M.; Shahverdiyev, Astan N.; Hasanov, Vaqif H.

    2005-01-01

    The (p, ρ, T) of methanol, ethylbenzene and (methanol + benzene) and (methanol + ethylbenzene) at temperatures between (290 and 500) K and pressures in the range (0.1 to 60) MPa have been measured with a magnetic suspension densimeter with an uncertainty of ±0.1%. Our measurements with methanol deviate from the literature values by less than 0.2%. The (p, ρ, T) measurements were fitted with experimental uncertainties by an empirical equation. The temperature and mole fraction dependence of the coefficients of the equation of state are presented

  15. Pembuatan Katalis Cu/ZnO/Al2O3 untuk Proses Steam Reforming Metanol menjadi Hidrogen sebagai Bahan Bakar Alternatif

    Directory of Open Access Journals (Sweden)

    Husni Husin

    2010-06-01

    Full Text Available Study on the use of copper zinc oxide supported on alumina catalyst for steam reforming of methanol to hydrogen has been done. The aim of this work is to study the catalytic properties of copper based catalysts used in the steam reforming of methanol. This method is known as one of the most favorable catalytic processes for producing hydrogen on-board. The catalyst was prepared by impregnation method with Cu loading of 5%, 10%, and 15%,. The X-ray diffraction pattern shows that the catalyst compositions are Cu, CuO, ZnO, and Al2O3. The reactions were carried out in the fixed bed tubular reactor operating at temperatures of 150oC, 200oC, 250oC, 300oC, and 350oC and atmospheric pressure. The product was analyzed using Shimadzu Gas Chromatography GC 8A with mole sieve 5A and porapak-N column 80/100 mesh. The performance of the catalyst shows that the highest methanol conversion was 86% over Cu/ZnO/Al2O3 catalyst with 15% of Cu loading. The selectivity and yield of hydrogen was 66% and 57% respectively over Cu/ZnO/Al2O3 catalyst with 15% of Cu loading. Selectivity of carbon dioxide is 18% over Cu/ZnO/Al2O3 catalyst with 15% of Cu loading at 300oC. Keywords: alumina oxide catalyst, copper zinc oxide, hydrogen, impregnation

  16. Steam turbine installations

    International Nuclear Information System (INIS)

    Bainbridge, A.

    1976-01-01

    The object of the arrangement described is to enable raising steam for driving steam turbines in a way suited to operating with liquid metals, such as Na, as heat transfer medium. A preheated water feed, in heat transfer relationship with the liquid metals, is passed through evaporator and superheater stages, and the superheated steam is supplied to the highest pressure stage of the steam turbine arrangement. Steam extracted intermediate the evaporator and superheater stages is employed to provide reheat for the lower pressure stage of the steam turbine. Only a major portion of the preheated water feed may be evaporated and this portion separated and supplied to the superheater stage. The feature of 'steam to steam' reheat avoids a second liquid metal heat transfer and hence represents a simplification. It also reduces the hazard associated with possible steam-liquid metal contact. (U.K.)

  17. Methanol Fuel Cell

    Science.gov (United States)

    Voecks, G. E.

    1985-01-01

    In proposed fuel-cell system, methanol converted to hydrogen in two places. External fuel processor converts only part of methanol. Remaining methanol converted in fuel cell itself, in reaction at anode. As result, size of fuel processor reduced, system efficiency increased, and cost lowered.

  18. Computational fluid dynamics validation study of steam condensation on the containment walls

    International Nuclear Information System (INIS)

    Gera, B.; Sharma, P.K.; Singh, R.K.; Vaze, K.K.

    2012-01-01

    In water cooled power reactors, significant quantities of hydrogen could be produced following a severe accident (loss-of-coolant-accident along with non availability of emergency core cooling system). A sound understanding of dispersion, stratification and diffusion of released hydrogen during severe accidents is, therefore, of practical importance and use to better understand the possibility of ignition, combustion and explosion of such releases within the context of containment safety. The presence of air and steam in the containment atmosphere also affects the hydrogen distribution as steam condensation takes place at containment walls in presence of non condensable and bulk of the mixture diffuses towards wall. The application of general purpose CFD codes for the analysis of the hydrogen behaviour within NPP containments during severe accidents has been increasing over past few years. The commercial CFD codes generally do not have built-in steam condensations models. In the present work, the adaptation of a commercial multipurpose code to this kind of problem is explained, i.e. by the implementation of models for steam condensation onto walls in presence of non-condensable gases. Steam condensation was modeled using the Uchida correlation, which was originally developed to be used for 'lumped' (volume-averaged) modeling of steam condensation in the presence of non-condensable gases. The Uchida correlation is based on experiments on natural convection from relatively small vertical plates. The present methodology has been validated against experimental data from the TOSQAN and COPAIN experimental facilities. (orig.)

  19. Methanol-Tolerant Cathode Catalyst Composite For Direct Methanol Fuel Cells

    Science.gov (United States)

    Zhu, Yimin; Zelenay, Piotr

    2006-03-21

    A direct methanol fuel cell (DMFC) having a methanol fuel supply, oxidant supply, and its membrane electrode assembly (MEA) formed of an anode electrode and a cathode electrode with a membrane therebetween, a methanol oxidation catalyst adjacent the anode electrode and the membrane, an oxidant reduction catalyst adjacent the cathode electrode and the membrane, comprises an oxidant reduction catalyst layer of a platinum-chromium alloy so that oxidation at the cathode of methanol that crosses from the anode through the membrane to the cathode is reduced with a concomitant increase of net electrical potential at the cathode electrode.

  20. Thermal-hydraulic tests of steam-generator tube-support-plate crevices. Volume 2. Appendixes I through S. Final report

    International Nuclear Information System (INIS)

    Cassell, D.S.; Vroom, D.W.

    1983-01-01

    A test program was conducted to determine for selected steam generator tube supports the thermal/hydraulic conditions at the inception of dryout as indicated by a tube wall temperature excursion, to determine the pressure drop across the supports, and to obtain photographic documentation of the flow upstream and downstream of the supports. A multi-tube steam generator model was used and testing performed over the range of typcal PWR steam generator operating conditions. These appendices contain information on instrumentation calibration, test model and loop calibration, error analysis, test model thermal-hydraulic analyses, index of lab materials and log sheets, index of two-phase flow still photographs, index of high speed movies and video, test data printouts, test model and loop fabrication drawings, procedure for silver brazing tubewall thermocouples, and procedure for esablishing tube-tube support line contact

  1. Methanol fuel update

    International Nuclear Information System (INIS)

    Colledge, R.; Spacek, J.

    1992-01-01

    An overview is presented of methanol fuel developments, with particular reference to infrastructure, supply and marketing. Methanol offers reduced emissions, easy handling, is cost effective, can be produced from natural gas, coal, wood, or municipal waste, is a high performance fuel, is safer than gasoline, and contributes to energy security. Methanol supply, environmental benefits, safety/health issues, economics, passenger car economics, status of passenger car technology, buses, methanol and the prosperity initiative, challenges to implementation, and the role of government and original equipment manufacturers are discussed. Governments must assist in the provision of methanol refuelling infrastructure, and in providing an encouraging regulatory atmosphere. Discriminatory and inequitable taxing methods must be addressed, and an air quality agenda must be defined to allow the alternative fuel industry to respond in a timely manner

  2. Hydrogen production by ethanol steam reforming over co-hydrotalcites having basic sites

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, J.L.; Salmones, J.; Garcia, L.A.; Ponce, A.; Zeifert, B.; Fuentes, G.A. [Univ. Autonoma Metropolitana-Azcapotzalco, Mexico City (Mexico); Contreras, J.L.; Salmones, J.; Garcia, L.A.; Ponce, A.; Zeifert, B.; Fuentes, G.A. [Inst. Politecnico Nacional, Mexico City (Mexico); Contreras, J.L.; Salmones, J.; Garcia, L.A.; Ponce, A.; Zeifert, B.; Fuentes, G.A. [Univ. Autonoma Metropolitana-Iztapalapa, Mexico City (Mexico)

    2008-04-15

    The catalytic steam reforming process can be used to produce hydrogen from ethanol for use in fuel cells. In comparison to methanol or gasoline, ethanol offers many advantages, notably, it is a renewable resource and neutral with respect to emissions of carbon dioxide (CO{sub 2}); it is less toxic; it can be readily stored without handling risk; and it can be obtained in large quantities from biomass. The reaction of ethanol with steam is strongly endothermic and can form undesirable products during the reaction. This article presented a study that combined, for the first time, the catalytic properties of cobalt (Co) with a new family of supports that are the hydrotalcites of high surface area and with basic sites. Co/Hydrotalcite catalysts were prepared, characterized and evaluated during the steam reforming of ethanol from 500 to 650 degrees Celsius. The article discussed the experiment, including the preparation of catalysts; characterization of solids; and catalytic evaluation. Scanning electron microscopy and x-ray diffraction studies were also described. Results were described in terms of area and pore volume distribution; thermogravimetric analysis and differential thermal analysis; temperature-programmed desorption (TPD) of CO{sub 2}; scanning electron microscopy; x-ray diffraction; the crystalline nature of cobalt; and ethanol steam-reforming reaction. It was concluded that the Co concentration was enriched on the hydrotalcite surface. In addition, a direct relationship between the Co concentration and the total basicity was found. A direct relationship between basicity and the conversion was also found. 27 refs., 3 tabs., 12 figs.

  3. Steam Digest 2002

    Energy Technology Data Exchange (ETDEWEB)

    2003-11-01

    Steam Digest 2002 is a collection of articles published in the last year on steam system efficiency. DOE directly or indirectly facilitated the publication of the articles through it's BestPractices Steam effort. Steam Digest 2002 provides a variety of operational, design, marketing, and program and program assessment observations. Plant managers, engineers, and other plant operations personnel can refer to the information to improve industrial steam system management, efficiency, and performance.

  4. Steam-Generator Integrity Program/Steam-Generator Group Project

    International Nuclear Information System (INIS)

    1982-10-01

    The Steam Generator Integrity Program (SGIP) is a comprehensive effort addressing issues of nondestructive test (NDT) reliability, inservice inspection (ISI) requirements, and tube plugging criteria for PWR steam generators. In addition, the program has interactive research tasks relating primary side decontamination, secondary side cleaning, and proposed repair techniques to nondestructive inspectability and primary system integrity. The program has acquired a service degraded PWR steam generator for research purposes. This past year a research facility, the Steam Generator Examination Facility (SGEF), specifically designed for nondestructive and destructive examination tasks of the SGIP was completed. The Surry generator previously transported to the Hanford Reservation was then inserted into the SGEF. Nondestructive characterization of the generator from both primary and secondary sides has been initiated. Decontamination of the channelhead cold leg side was conducted. Radioactive field maps were established in the steam generator, at the generator surface and in the SGEF

  5. Steam drums

    International Nuclear Information System (INIS)

    Crowder, R.

    1978-01-01

    Steam drums are described that are suitable for use in steam generating heavy water reactor power stations. They receive a steam/water mixture via riser headers from the reactor core and provide by means of separators and driers steam with typically 0.5% moisture content for driving turbines. The drums are constructed as prestressed concrete pressure vessels in which the failure of one or a few of the prestressing elements does not significantly affect the overall strength of the structure. The concrete also acts as a radiation shield. (U.K.)

  6. Numerical study of methanol–steam reforming and methanol–air catalytic combustion in annulus reactors for hydrogen production

    International Nuclear Information System (INIS)

    Chein, Reiyu; Chen, Yen-Cho; Chung, J.N.

    2013-01-01

    Highlights: ► Performance of mini-scale integrated annulus reactors for hydrogen production. ► Flow rates fed to combustor and reformer control the reactor performance. ► Optimum performance is found from balance of flow rates to combustor and reformer. ► Better performance can be found when shell side is designed as combustor. -- Abstract: This study presents the numerical simulation on the performance of mini-scale reactors for hydrogen production coupled with liquid methanol/water vaporizer, methanol/steam reformer, and methanol/air catalytic combustor. These reactors are designed similar to tube-and-shell heat exchangers. The combustor for heat supply is arranged as the tube or shell side. Based on the obtained results, the methanol/air flow rate through the combustor (in terms of gas hourly space velocity of combustor, GHSV-C) and the methanol/water feed rate to the reformer (in terms of gas hourly space velocity of reformer, GHSV-R) control the reactor performance. With higher GHSV-C and lower GHSV-R, higher methanol conversion can be achieved because of higher reaction temperature. However, hydrogen yield is reduced and the carbon monoxide concentration is increased due to the reversed water gas shift reaction. Optimum reactor performance is found using the balance between GHSV-C and GHSV-R. Because of more effective heat transfer characteristics in the vaporizer, it is found that the reactor with combustor arranged as the shell side has better performance compared with the reactor design having the combustor as the tube side under the same operating conditions.

  7. Hybrid heat recovery - flat plate Stirling engine system

    International Nuclear Information System (INIS)

    Bogdanizh, A.M.; Budin, R.; Sutlovizh, I.

    2000-01-01

    In this paper, the possibility of process condensate heat recovery for boiler water preheating as well as for combined heat and power production for chosen process in textile industry has been investigated. The garment industry requires low pressure process steam or hot water for which production expensive fossil fuel should be used. Fuel usage can be reduced by various energy conservation methods. During the process a great quantity of hot condensate or waste hot water is rejected in the sewage system. To reduce heat wastes and improve technological process this condensate could be returned to the boiler for feed water preheating. When 60% condensate is returned to the steam generator about 8 % natural gas is saved. The rest of the condensate should be used for driving low temperature flat plate Stirling motor the advantage of the flat plate Stirling engine is ability to work at low temperatures. This engine produces electrical energy which can put in motion an electrogenerator in the same plant. While Stirling engine can be used electrical power and economical effect could be much greater using such a hybrid system the process waste heat is not only converted into useful work but at the same time thermal pollution is greatly diminished. (Author)

  8. Repair technique for steam generator tubes using electroforming

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Jeong, Hyun Kyu; Seo, Moon Hong

    2001-07-01

    Pickering B CANDU Unit 5 had experienced leakage at sleeve/tube joint due to severe and local pitting in 1992{delta}1993. One year later, OHT developed electrosleeving techniques for steam generator tube repair which was applied at Pickering B CANDU Unit 5, Oconee Unit 1 and Callaway in 1994, 1995 and 1999 respectively. In the results of electrosleeved tube test, electrosleeve materials were stronger than mother tubes in mechanical properties and corrosion resistance under design criteria. Two analytical models were originally developed for estimating the failure temperature under severe accident transients. Electrosleeve, a structural layer of fine grained nickel is electroformed onto the strike by circulating an aqueous solution of Ni sulfate or sulfamate with NiCO3. The patents published by FTI said that the electrolyte for electroforming the structural layer contains a pinning agent to inhibit growth of metal grains in the electroformed layer. The pinning agent contains phosphoric, phosphorous acid, molybdenum. In localization of electrosleeving, there are some problems like as 1)low plating rate, 2)high residual stress, 3)alloy composition, 4)low material properties at high temperature. Ni-Fe plating exhibit anomalous codeposition; that is less noble metal, Fe, deposits preferentially to the more noble metal, Ni. Ductility decrease and residual stress increase with increase of Fe content in plate layer. Addition of particle size of 10{delta}400{mu}m makes residual stress compressive in plate layer. Composite plating show excellent high temperature properties.

  9. Repair technique for steam generator tubes using electroforming

    International Nuclear Information System (INIS)

    Kim, Seung Ho; Jeong, Hyun Kyu; Seo, Moon Hong

    2001-07-01

    Pickering B CANDU Unit 5 had experienced leakage at sleeve/tube joint due to severe and local pitting in 1992δ1993. One year later, OHT developed electrosleeving techniques for steam generator tube repair which was applied at Pickering B CANDU Unit 5, Oconee Unit 1 and Callaway in 1994, 1995 and 1999 respectively. In the results of electrosleeved tube test, electrosleeve materials were stronger than mother tubes in mechanical properties and corrosion resistance under design criteria. Two analytical models were originally developed for estimating the failure temperature under severe accident transients. Electrosleeve, a structural layer of fine grained nickel is electroformed onto the strike by circulating an aqueous solution of Ni sulfate or sulfamate with NiCO3. The patents published by FTI said that the electrolyte for electroforming the structural layer contains a pinning agent to inhibit growth of metal grains in the electroformed layer. The pinning agent contains phosphoric, phosphorous acid, molybdenum. In localization of electrosleeving, there are some problems like as 1)low plating rate, 2)high residual stress, 3)alloy composition, 4)low material properties at high temperature. Ni-Fe plating exhibit anomalous codeposition; that is less noble metal, Fe, deposits preferentially to the more noble metal, Ni. Ductility decrease and residual stress increase with increase of Fe content in plate layer. Addition of particle size of 10δ400μm makes residual stress compressive in plate layer. Composite plating show excellent high temperature properties

  10. An Improved Steam Injection Model with the Consideration of Steam Override

    Directory of Open Access Journals (Sweden)

    He Congge

    2017-01-01

    Full Text Available The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, the equation for the reservoir heat efficiency with the consideration of steam override was developed. Next, predicted results of the new model were compared with these of another analytical model and CMG STARS (a mature commercial reservoir numerical simulator to verify the accuracy of the new mathematical model. Finally, based on the validated model, we analyzed the effects of injection rate, steam quality and reservoir thickness on the reservoir heat efficiency. The results show that the new model can be simplified to the classic model (Marx-Langenheim model under the condition of the steam override being not taken into account, which means the Marx-Langenheim model is corresponding to a special case of this new model. The new model is much closer to the actual situation compared to the Marx-Langenheim model because of considering steam override. Moreover, with the help of the new model, it is found that the reservoir heat efficiency is not much affected by injection rate and steam quality but significantly influenced by reservoir thickness, and to ensure that the reservoir can be heated effectively, the reservoir thickness should not be too small.

  11. Nickel electroplating of steam generator tubes (kiss sleeving process)

    International Nuclear Information System (INIS)

    Michaut, B.

    1988-01-01

    This process, the nickel electroplating of steam generator tubes, has been jointly developed under a Belgatom (Laborelec) and Framatome agreement with shared experience gained by both companies, industrial applications being under the responsibility of Framatome. Application of the coating in zones where residual stresses or cracks are present prevents contact between the primary water and the tube, which stops the stress corrosion process. In the Doel 2 plant, 91 tubes have been plated since 1985, and different sets of parameters have been used for comparison purposes. Among these tubes, 9 have been preventively plugged because of defective plating, 9 have been pulled out for laboratory examinations, 2 just after plating and 7 after 1 or 2 yr of service. There are 73 plated tubes still in service. From the tests that were performed, it was possible to select an optimized set of parameters guaranteeing the following properties: bridging of existing cracks and good behavior of the coating in relevant zones, good adhesion to the Inconel tube, high ductility, low residual stresses, thermal shock resistance, corrosion resistance, erosion resistance, and low cobalt content. The licensability of this process is being completed. It is based first on the leak-before-break concept to determine the characteristics of the nickel plating, thickness in particular, and second on the inspectability of ultrasonic testing methods

  12. Evaluation of Analgesic Activity of the Methanol Extract from the Galls of Quercus infectoria (Olivier in Rats

    Directory of Open Access Journals (Sweden)

    Sook-Ha Fan

    2014-01-01

    Full Text Available The present study aims to investigate the analgesic activity of the methanol extract of the galls of Quercus infectoria in rats using hot plate and tail-flick methods. The extract was administered intraperitoneally at a dose of 20 mg/kg while morphine sulfate and sodium salicylate (10 mg/kg served as standards. The methanol extract exhibited significant analgesic activity in the tail-flick model (P<0.05 by increasing the reaction time of the rats to 8.0 sec at 30 min after treatment in comparison to control (4.4 sec. Morphine sulfate produced a reaction time of 11.9 sec in the same test. At the peak of activity (30 min, the extract produced maximum possible analgesia (MPA of 34.2%, whilst morphine sulfate achieved a peak MPA of 70.9%. No analgesic effects have been observed using sodium salicylate in the tail-flick model. In the same model, the extract and sodium salicylate demonstrated comparable reaction times. Tail-flick is a better method to evaluate analgesic activity as no significant results were observed for all treatments using hot plate with the exception of morphine sulfate, which showed significant results only at 45 and 60 min after treatment. In conclusion, the methanol extract of the galls of Quercus infectoria displayed analgesic activity.

  13. Ontario Hydro's operating experience with steam generators with specifics on Bruce A and Bruce B problems

    Energy Technology Data Exchange (ETDEWEB)

    Eatock, J W; Patterson, R W [Ontario Hydro, Toronto, ON (Canada); Dyck, R W [Ontario Hydro, Central Production Services Division, Toronto, ON (Canada)

    1991-04-01

    The performance of the steam generators in Ontario Hydro nuclear power stations is reviewed. This performance has generally been outstanding compared to world averages, with very low tube failure and plugging rates. Steam generator problems have made only minor contributions to Ontario Hydro nuclear station incapability factors. The mechanisms responsible for the the observed tube degradation and failures are described. The majority of the leaks have been due fatigue in the U-bend of the Bruce 'A' steam generators. There have been very few failures attributed to corrosion of the three tube materials used in Ontario Hydro steam generators. Recent performance has been deteriorating primarily due to deposit accumulation in the steam generators. Plugging of the broached holes in the upper support plates at Bruce 'A' has caused some derating of two units. Increases have been observed in the primary heat transport system reactor inlet temperature of several units. These increases may be attributed to steam generator tube surface fouling. In addition, several units have accumulated deep, hard sludge piles on the tube sheet, although little damage been observed. Recently some fretting of tubes has been observed at BNGSB in the U-bend support region. Remedial measures are being taken to address the current problems. Solutions are being evaluated to reduce the generation of corrosion products in the feedtrain and their subsequent transport to the steam generators. (author)

  14. Ontario Hydro's operating experience with steam generators with specifics on Bruce A and Bruce B problems

    International Nuclear Information System (INIS)

    Eatock, J.W.; Patterson, R.W.; Dyck, R.W.

    1991-01-01

    The performance of the steam generators in Ontario Hydro nuclear power stations is reviewed. This performance has generally been outstanding compared to world averages, with very low tube failure and plugging rates. Steam generator problems have made only minor contributions to Ontario Hydro nuclear station incapability factors. The mechanisms responsible for the the observed tube degradation and failures are described. The majority of the leaks have been due fatigue in the U-bend of the Bruce 'A' steam generators. There have been very few failures attributed to corrosion of the three tube materials used in Ontario Hydro steam generators. Recent performance has been deteriorating primarily due to deposit accumulation in the steam generators. Plugging of the broached holes in the upper support plates at Bruce 'A' has caused some derating of two units. Increases have been observed in the primary heat transport system reactor inlet temperature of several units. These increases may be attributed to steam generator tube surface fouling. In addition, several units have accumulated deep, hard sludge piles on the tube sheet, although little damage been observed. Recently some fretting of tubes has been observed at BNGSB in the U-bend support region. Remedial measures are being taken to address the current problems. Solutions are being evaluated to reduce the generation of corrosion products in the feedtrain and their subsequent transport to the steam generators. (author)

  15. Experimental study on methanol recovery through flashing vaporation in continuous production of biodiesel via supercritical methanol

    International Nuclear Information System (INIS)

    Wang Cunwen; Chen Wen; Wang Weiguo; Wu Yuanxin; Chi Ruan; Tang Zhengjiao

    2011-01-01

    To improve the oil conversion, high methanol/oil molar ratio is required in the continuous production of biodiesel via supercritical methanol transesterification in tubular reactor. And thus the subsequent excess methanol recovery needs high energy consumption. Based on the feature of high temperature and high pressure in supercritical methanol transesterification, excess methanol recovery in reaction system by flashing vaporation is conducted and the effect of reaction temperature, reaction pressure and flashing pressure on methanol recovery and methanol concentration in gas phase is discussed in detail in this article. Results show that at the reaction pressure of 9-15 MPa and the reaction temperature of 240-300 o C, flashing pressure has significant influence on methanol recovery and methanol content in gas phase, which can be effectively improved by reducing flashing pressure. At the same time, reaction temperature and reaction pressure also have an important effect on methanol recovery and methanol content in gas phase. At volume flow of biodiesel and methanol 1:2, tubular reactor pressure 15 MPa, tubular reactor temperature 300 o C and the flashing pressure 0.4 MPa, methanol recovery is more than 85% and methanol concentration of gas phase (mass fraction) is close to 99% after adiabatic braising; therefore, the condensate liquid of gas phase can be injected directly into methanol feedstock tank to be recycled. Research abstracts: Biodiesel is an important alternative energy, and supercritical methanol transesterification is a new and green technology to prepare biodiesel with some obvious advantages. But it also exists some problems: high reaction temperature, high reaction pressure and large molar ratio of methanol/oil will cause large energy consumption which restricts supercritical methanol for the industrial application of biodiesel. So a set of tubular reactor-coupled flashing apparatus is established for continuous preparing biodiesel in supercritical

  16. Process to repair a steam generator tube by inserting a tubular sleeve and the associated sleeve

    International Nuclear Information System (INIS)

    Gaudin, J.P.

    1986-01-01

    The tubular sleeve is introduced in the tube and is mechanically expanded inside the tube plate, and is diametrally expanded at its upper part within the tube and outside the tube plate. Tightness is ensured by brazing the end part of the sleeve within the tube. The end part of the sleeve is brazed by melting of brazing metal previously applied to the outer surface of the sleeve of its end region. The invention applies more particularly to steam generators of pressurized water nuclear reactors [fr

  17. Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

    Science.gov (United States)

    Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

    2017-02-01

    A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

  18. Preparation and structural characterization of SnO2 and GeO2 methanol steam reforming thin film model catalysts by (HR)TEM

    International Nuclear Information System (INIS)

    Lorenz, Harald; Zhao Qian; Turner, Stuart; Lebedev, Oleg I.; Van Tendeloo, Gustaaf; Kloetzer, Bernhard; Rameshan, Christoph; Penner, Simon

    2010-01-01

    Structure, morphology and composition of different tin oxide and germanium oxide thin film catalysts for the methanol steam reforming (MSR) reaction have been studied by a combination of (high-resolution) transmission electron microscopy, selected area electron diffraction, dark-field imaging and electron energy-loss spectroscopy. Deposition of the thin films on NaCl(0 0 1) cleavage faces has been carried out by thermal evaporation of the respective SnO 2 and GeO 2 powders in varying oxygen partial pressures and at different substrate temperatures. Preparation of tin oxide films in high oxygen pressures (10 -1 Pa) exclusively resulted in SnO phases, at and above 473 K substrate temperature epitaxial growth of SnO on NaCl(0 0 1) leads to well-ordered films. For lower oxygen partial pressures (10 -3 to 10 -2 Pa), mixtures of SnO and β-Sn are obtained. Well-ordered SnO 2 films, as verified by electron diffraction patterns and energy-loss spectra, are only obtained after post-oxidation of SnO films at temperatures T ≥ 673 K in 10 5 Pa O 2 . Preparation of GeO x films inevitably results in amorphous films with a composition close to GeO 2 , which cannot be crystallized by annealing treatments in oxygen or hydrogen at temperatures comparable to SnO/SnO 2 . Similarities and differences to neighbouring oxides relevant for selective MSR in the third group of the periodic system (In 2 O 3 and Ga 2 O 3 ) are also discussed with the aim of cross-correlation in formation of nanomaterials, and ultimately, also catalytic properties.

  19. Short-term inhalation toxicity of methanol, gasoline, and methanol/gasoline in the rat.

    Science.gov (United States)

    Poon, R; Chu, I; Bjarnason, S; Vincent, R; Potvin, M; Miller, R B; Valli, V E

    1995-01-01

    Four- to five-week-old male and female Sprague Dawley rats were exposed to vapors of methanol (2500 ppm), gasoline (3200 ppm), and methanol/gasoline (2500/3200 ppm, 570/3200 ppm) six hours per day, five days per week for four weeks. Control animals were exposed to filtered room air only. Depression in body weight gain and reduced food consumption were observed in male rats, and increased relative liver weight was detected in rats of both sexes exposed to gasoline or methanol/gasoline mixtures. Rats of both sexes exposed to methanol/gasoline mixtures had increased relative kidney weight and females exposed to gasoline and methanol/gasoline mixtures had increased kidney weight. Decreased serum glucose and cholesterol were detected in male rats exposed to gasoline and methanol/gasoline mixtures. Decreased hemoglobin was observed in females inhaling vapors of gasoline and methanol/gasoline at 570/3200 ppm. Urine from rats inhaling gasoline or methanol/gasoline mixtures had up to a fourfold increase in hippuric acid, a biomarker of exposure to the toluene constituent of gasoline, and up to a sixfold elevation in ascorbic acid, a noninvasive biomarker of hepatic response. Hepatic mixed-function oxidase (aniline hydroxylase, aminopyrine N-demethylase and ethoxyresorufin O-deethylase) activities and UDP-glucuronosyltransferase activity were elevated in rats exposed to gasoline and methanol/gasoline mixtures. Histopathological changes were confined to very mild changes in the nasal passages and in the uterus, where decreased incidence or absence of mucosal and myometrial eosinophilia was observed in females inhaling gasoline and methanol/gasoline at 570/3200 ppm. It was concluded that gasoline was largely responsible for the adverse effects, the most significant of which included depression in weight gain in the males, increased liver weight and hepatic microsomal enzyme activities in both sexes, and suppression of uterine eosinophilia. No apparent interactive effects

  20. Steam sterilization does not require saturated steam

    NARCIS (Netherlands)

    van Doornmalen Gomez Hoyos, J. P.C.M.; Paunovic, A.; Kopinga, K.

    2017-01-01

    The most commonly applied method to sterilize re-usable medical devices in hospitals is steam sterilization. The essential conditions for steam sterilization are derived from sterilization in water. Microbiological experiments in aqueous solutions have been used to calculate various time–temperature

  1. Gentilly 2 divider plate replacement

    International Nuclear Information System (INIS)

    Forest, J.; Klisel, E.; McClellan, G.; Schnelder, W.

    1995-01-01

    The steam generators at the Gentilly 2 Nuclear Plant in operation since 1983 were built with primary divider plates of a bolted panel configuration. During a routine outage inspection, it was noted that two bolts had dislodged from the divider and were located lying in the primary head. Subsequent inspections revealed erosion damage to a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. After evaluation of various options, it was decided that the panel type dividers would be replaced with a single piece floating design. The divider itself was to be of a one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat bar was provided. To counteract erosion concerns, the new divider is fitted with erosion resistant inserts or weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage in the design and manufacture of the components, the issue of divider strength during LOCA conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider to a variety of small and large LOCA conditions. The paper describes the diagnosis of the original divider plates and the design, manufacture, field mobilization, installation and subsequent operation of the replacement divider plates. (author)

  2. Design features of Advanced Power Reactor (APR) 1400 steam generator

    International Nuclear Information System (INIS)

    Park, Tae-Jung; Park, Jun-Soo; Kim, Moo-Yong

    2004-01-01

    Advanced Power Reactor 1400 (APR 1400) which is to achieve the improvement of the safety and economical efficiency has been developed by Korea Hydro and Nuclear Power Co., Ltd. (KHNP) with the support from industries and research institutes. The steam generator for APR 1400 is an evolutionary type from System 80 + , which is the recirculating U-tube heat exchanger with integral economizer. Compared to the System 80 + steam generator, it is focused on the improved design features, operating and design conditions of APR 1400 steam generator. Especially, from the operation experience of Korean Standard Nuclear Power Plant (KSNP) steam generator, the lessons-learned measures are incorporated to prevent the tube wear caused by flow-induced vibration (FIV). The concepts for the preventive design features against FIV are categorized to two fields; flow distribution and dynamic response characteristics. From the standpoint of flow distribution characteristics, the egg-crate flow distribution plate (EFDP) is installed to prevent the local excessive flow loaded on the most susceptible tube to wear. The parametric study is performed to select the optimum design with the efficient mitigation of local excessive flow. ATHOS3 Mod-01 is used and partly modified to analyze the flow field of the APR 1400 steam generator. In addition, the upper tube bundle support is designed to eliminate the presence of tube with a low natural frequency. Based on the improved upper tube bundle support, the modal analysis is performed and compared with that of System 80 + . Using the results of flow distribution and modal analysis, the two mechanisms of flow-induced vibration are investigated; fluid-elastic instability (FEI) and random turbulence excitation (RTE). (authors)

  3. Cleaning IBL secondary sludge in the tubular plate steam generators

    International Nuclear Information System (INIS)

    Montoro de Frutos, E.; Gonzalez Carballo, S.

    2012-01-01

    After cleanings Sludge Lancing using 250bar made from the center lane, identifies an area of solidified remaining sludge on the tube plate. Since late 2010, IBERDROLA-SAVAC has developed Inner System Bundle Lancing (IBL), which locally involves shooting a jet of water at high pressure 590bar directly impacting sludge areas within the tube bundle hard to detach and break into small pieces that can be extracted from GV through a closed circuit suction.

  4. Nickel electroplating as a remedy to steam generator tubing PWSCC

    International Nuclear Information System (INIS)

    Michaut, B.; Steltzlen, F.; Sala, B.; Laire, Ch.; Stubbe, J.

    1993-01-01

    Nickel plating appears to be a versatile process, as the application field, even if always used against PWSCC, is different from plant-to-plant. Its usage has been from a purely preventive action on tubes without defects, to a corrective action on through-wall cracked and leaking tubes. As a background for the large scale on-site operations of Doel 2 in 1990 (345 tubes) and Tihange 2 in 1992 (600 tubes), studies on four points are outlined, i.e. corrosion tests, stress measurements, sulfamate bath quality control, and in-service inspection. In conclusion, it appears that the nickel plating technique, following a case-by-case study, can often be a convenient remedy against Alloy 600 stress corrosion problems. New applications, in locations other than the steam generator field are under consideration

  5. Natural draft dry-type cooling tower for steam power plants

    International Nuclear Information System (INIS)

    Nasser, G.

    1976-01-01

    The task to build natural-draught dry cooling towers for large steam power plants as simple, compact, and economical as possible may be achieved by a combination of known features with the aid of the present application: the condenser elements built as piles of corrugated plates are arranged in the form of a truncated pyramid widened towards the top. For the cooling-air flow inlet openings for hot gas supplied from the lower part of the dome are provided. (UWI) [de

  6. Passive system with steam-water injector for emergency supply of NPP steam generators

    International Nuclear Information System (INIS)

    Il'chenko, A.G.; Strakhov, A.N.; Magnitskij, D.N.

    2009-01-01

    The calculation results of reliability indicators of emergency power supply system and emergency feed-water supply system of serial WWER-1000 unit are presented. To ensure safe water supply to steam generators during station blackout it was suggested using additional passive emergency feed-water system with a steam-water injector working on steam generators dump steam. Calculated analysis of steam-water injector operating capacity was conducted at variable parameters of steam at the entrance to injector, corresponding to various moments of time from the beginning of steam-and-water damping [ru

  7. Analysis of steam generator tube sections removed from Gentilly-2 nuclear generating station

    International Nuclear Information System (INIS)

    Semmler, J.; Lockley, A.J.; Doyon, D.

    2010-01-01

    In order to meet the requirements of CSA Standards CAN/CSA N285.4-94, which states, 'A section of one tube in a deposit region shall be removed from one steam generator for metallurgical examination', Gentilly-2 has been removing steam generator tube sections on a regular basis for analysis at Chalk River Laboratories. In 2009 April, sections from the hot leg and the cold leg of a steam generator tube were removed for detailed metallographic examination and characterization. The hot leg tube section covered the area from within the tube sheet up to below the second support plate, and the cold leg tube section covered the area from within the tube sheet to below the third preheater support plate. After a general visual and photographic examination, the area above the tube sheet on the hot leg side where the sludge pile is highest was examined in detail. Visual and macro-photography of the two tube sections within the tube sheet were also examined. Additional metallographic and surface examinations of both tube inner diameter and tube outer diameter, and surface roughness measurements of tube inner diameter were also completed. The surface activities (μCi/cm 2 ) of cold leg and hot leg specimens were measured before and after electrolytic descaling, and major and minor radionuclides were identified; a comparison of the surface activities for hot leg with the values for the cold leg were made. The results from the initial γ-spectroscopy measurements, and the measurements after the descaling of the specimens were used to estimate decontamination factors for each specimen and for each radionuclide. The tube specimens had thin outer diameter oxides; all four steam generators were chemically cleaned in 2005. All specimens had inner diameter deposits; the inner diameter deposits on the cold leg were heavier than those on the hot leg as expected. Primary side oxide loadings of specimens were used to estimate the total oxide inventory in 2009. The oxide

  8. Gentilly-2 and Point Lepreau divider plate replacement

    International Nuclear Information System (INIS)

    Schneider, W.; McClellan, G.; Weston, S.

    1996-01-01

    The steam generators at Hydro Quebec's Gentilly-2 and New Brunswick Power's Point Lepreau Nuclear Plants have been in operation since 1983, and were built with primary divider plates of a bolted panel configuration. During a routine outage inspection at Gentilly-2, it was noted that two bolts had dislodged from the divider plate and were located lying in the primary head. Subsequent inspections revealed erosion damage to a a substantial number of divider plate bolts and to a lesser extent, to the divider plate itself. After further inspection and repair the units were returned to operation, however, it was determined that a permanent replacement of the primary divider plates was going to be necessary. Upon evaluation of various options, it was decided that the panel type divider plates would be replaced with a single piece floating design. The divider plate itself was to be of one piece all-welded arrangement to be constructed from individual panels to be brought in through the manways. In view of the strength limitations of the bolted attachment of the upper seat bar to the tubesheet, a new welded seat was was provided. To counteract erosion concerns, the new divider plate is fitted with erosion resistant inserts of weld buildup and with improved sealing features in order to minimize leakage and erosion. At an advanced stage in the design and manufacture of the components, the issue of divider plate strength during loss of coolant accident (LOCA) conditions came into focus. Analysis was performed to determine the strength and/or failure characteristics of the divider plate to a variety of small and large LOCA conditions. Subsequently, Point Lepreau decided to replace their divider plates to address LOCA concerns. The paper describes the diagnosis of the original divider plates and the design. manufacture, field mobilization, installation and subsequent operation of the replacement divider plates. (author)

  9. A selective electrocatalyst-based direct methanol fuel cell operated at high concentrations of methanol.

    Science.gov (United States)

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-06-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag 2 S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm -2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol.

  10. A selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

    Science.gov (United States)

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-01-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm−2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol. PMID:28695199

  11. Repairing a steam generator tube by inserting a sheath

    International Nuclear Information System (INIS)

    Gaudin, J.P.

    1986-01-01

    According to the invention, the mechanical deformation of the sheath, realized by expansion in its end part opposite to the expanded end within the tube plate, is situated along a limited height, and the parameters of the said mechanical deformation are calculated according to the welding parameters applied consecutively. Besides, the said welding parameters are determined according to the initial mechanical deformation to obtain stress relaxation more particularly in the singular zones of the mechanical deformation. The present invention applies to the repair of PWR steam generator tubes [fr

  12. Antiasthmatic and antiallergic potential of methanolic extract of leaves of Ailanthus excelsa

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar

    2011-02-01

    Full Text Available The aim of study was antiasthmatic potential of methanolic extract of leaves of Ailanthus excelsa Roxb., Simaroubaceae. Traditionally or in Indian system of medicine, A. excelsa is used in the treatment of asthma, cough, colic pain, cancer, diabetes and also used as antispasmodic, antifertility, bronchodilator. Stem bark of A. excelsa already reported for its potential against asthma. The pollens of Ailanthus excelsa reported allergic in nature and the time of collection of leaves were important in this study, generally the flowering stage of plant was avoided for the collection due to maximum chance of pollens at that time. Methanolic extract of leaves of A. excelsa was evaluated using in vitro goat tracheal chain preparation model and in vivo- Milk induced leucocytosis, eosinophilia, Clonidine induced catalepsy in mice model while Passive paw anaphylaxis and Clonidine induced mast cell degranulation in rat model. The extract showed the presence of flavonoids, terpenoids, saponins, quassonoids and test was also positive for alkaloids and steroids. The extract also showed the presence of quercetin which is flavonoid and detected on the preparative TLC plate with the help of standard quercetin. Dose response studies of methanolic extract of leaves of A. excelsa Roxb. were conducted at 100 µg mL-1 in vitro and 100, 200, 400 mg kg-1 p.o. in vivo models. The treatment with methanolic extract of A. excelsa at different dose level showed the significant (*p<0.05, **p<0.01, ***p<0.001 antiasthmatic activity. Inhibition or decrease the release of inflammatory mediators potentiates the antiasthmatic as well as antiallergic activity of methanolic extract of leaves of A. excelsa.

  13. Effective visualization assay for alcohol content sensing and methanol differentiation with solvent stimuli-responsive supramolecular ionic materials.

    Science.gov (United States)

    Zhang, Li; Qi, Hetong; Wang, Yuexiang; Yang, Lifen; Yu, Ping; Mao, Lanqun

    2014-08-05

    This study demonstrates a rapid visualization assay for on-spot sensing of alcohol content as well as for discriminating methanol-containing beverages with solvent stimuli-responsive supramolecular ionic material (SIM). The SIM is synthesized by ionic self-assembling of imidazolium-based dication C10(mim)2 and dianionic 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) in water and shows water stability, a solvent stimuli-responsive property, and adaptive encapsulation capability. The rationale for the visualization assay demonstrated here is based on the combined utilization of the unique properties of SIM, including its water stability, ethanol stimuli-responsive feature, and adaptive encapsulation capability toward optically active rhodamine 6G (Rh6G); the addition of ethanol into a stable aqueous dispersion of Rh6G-encapsulated SIM (Rh6G-SIM) destructs the Rh6G-SIM structure, resulting in the release of Rh6G from SIM into the solvent. Alcohol content can thus be visualized with the naked eyes through the color change of the dispersion caused by the addition of ethanol. Alcohol content can also be quantified by measuring the fluorescence line of Rh6G released from Rh6G-SIM on a thin-layer chromatography (TLC) plate in response to alcoholic beverages. By fixing the diffusion distance of the mobile phase, the fluorescence line of Rh6G shows a linear relationship with alcohol content (vol %) within a concentration range from 15% to 40%. We utilized this visualization assay for on-spot visualizing of the alcohol contents of three Chinese commercial spirits and discriminating methanol-containing counterfeit beverages. We found that addition of a trace amount of methanol leads to a large increase of the length of Rh6G on TLC plates, which provides a method to identify methanol adulterated beverages with labeled ethanol content. This study provides a simple yet effective assay for alcohol content sensing and methanol differentiation.

  14. Design and Operation of an Electrochemical Methanol Concentration Sensor for Direct Methanol Fuel Cell Systems

    Science.gov (United States)

    Narayanan, S. R.; Valdez, T. I.; Chun, W.

    2000-01-01

    The development of a 150-Watt packaged power source based on liquid feed direct methanol fuel cells is being pursued currently at the Jet propulsion Laboratory for defense applications. In our studies we find that the concentration of methanol in the fuel circulation loop affects the electrical performance and efficiency the direct methanol fuel cell systems significantly. The practical operation of direct methanol fuel cell systems, therefore, requires accurate monitoring and control of methanol concentration. The present paper reports on the principle and demonstration of an in-house developed electrochemical sensor suitable for direct methanol fuel cell systems.

  15. The `ASCAB` process of producing synthesis gas (methanol, ammonia) or medium joule gas from lignin-cellulose materials (wood, sugar cane wastes, peat, straw, agricultural wastes)

    Energy Technology Data Exchange (ETDEWEB)

    Carre, J

    1988-12-31

    The aim of this work is to relate the build a demonstration unit at a small city in France, on the principle of pressurized gasification of lignin-cellulose biomass with oxygen and steam, for the production of methanol, ammonia and low btu gases. In another type of application, the process should also be used for the incineration of some industrial wastes. (author) 8 figs., 1 tab.

  16. Direct Methanol Fuel Cell, DMFC

    Directory of Open Access Journals (Sweden)

    Amornpitoksuk, P.

    2003-09-01

    Full Text Available Direct Methanol Fuel Cell, DMFC is a kind of fuel cell using methanol as a fuel for electric producing. Methanol is low cost chemical substance and it is less harmful than that of hydrogen fuel. From these reasons it can be commercial product. The electrocatalytic reaction of methanol fuel uses Pt-Ru metals as the most efficient catalyst. In addition, the property of membrane and system designation are also effect to the fuel cell efficient. Because of low power of methanol fuel cell therefore, direct methanol fuel cell is proper to use for the energy source of small electrical devices and vehicles etc.

  17. HTGR steam generator development

    International Nuclear Information System (INIS)

    Schuetzenduebel, W.G.; Hunt, P.S.; Weber, M.

    1976-01-01

    More than 40 gas-cooled reactor plants have produced in excess of 400 reactor years of operating experience which have proved a reasonably high rate of gas-cooled reactor steam generator availability. The steam generators used in these reactors include single U-tube and straight-tube steam generators as well as meander type and helically wound or involute tube steam generators. It appears that modern reactors are being equipped with helically wound steam generators of the once-through type as the end product of steam generator evolution in gas-cooled reactor plants. This paper provides a general overview of gas-cooled reactor steam generator evolution and operating experience and shows how design criteria and constraints, research and development, and experience data are factored into the design/development of modern helically wound tube steam generators for the present generation of gas-cooled reactors

  18. Response of the steam generator VVER 1000 to a steam line break

    International Nuclear Information System (INIS)

    Novotny, J.; Novotny, J. Jr.

    2003-01-01

    Dynamic effects of a steam line break in the weld of the steam pipe and the steam collector on the steam generator system are analyzed. Modelling of a steam line break may concern two cases. The steam line without a restraint and the steam line protected by a whip restraint with viscous elements applied at the postulated break cross-section. The second case is considered. Programme SYSTUS offers a special element the stiffness and viscous damping coefficients of which may be defined as dependent on the relative displacement and velocity of its nodes respectively. A circumferential crack is simulated by a sudden decrease of longitudinal and lateral stiffness coefficients of these special SYSTUS elements to zero. The computation has shown that one can simulate the pipe to behave like completely broken during a time interval of 0,0001 s or less. These elements are used to model the whip restraint with viscous elements and viscous dampers of the GERB type as well. In the case of a whip restraint model the stiffness coefficient-displacement relation and damping coefficient - velocity relation are chosen to fit the given characteristics of the restraint. The special SYSTUS elements are used to constitute Maxwell elements modelling the elasto-plastic and viscous properties of the GERB dampers applied to the steam generator. It has been ascertained that a steam line break at the postulated weld crack between the steam pipe and the steam generator collector cannot endanger the integrity of the system even in a case of the absence of a whip restraint effect. (author)

  19. Methanol production by Mycobacterium smegmatis

    International Nuclear Information System (INIS)

    Weisman, L.S.; Ballou, C.E.

    1988-01-01

    Mycobacterium smegmatis cells produce [ 3 H]methanol when incubated with [methyl- 3 H]methionine. The methanol is derived from S-adenosylmethionine rather than methyltetrahydrofolate. M. smegmatis cells carboxymethylate several proteins, and some of the methanol probably results from their demethylation, but most of the methanol may come from an unidentified component with a high gel mobility. Although methanol in the medium reached 19 μM, it was not incorporated into the methylated mannose polysaccharide, a lipid carrier in this organism

  20. Transduced for determining if steam generator tubes are locked in at support plate

    International Nuclear Information System (INIS)

    Hayes, J.K.

    1984-01-01

    A nuclear steam generator is described which includes a vessel, means to introduce vaporizable fluid into the bottom portion of the vessel, an outlet near the top through which vapor is discharged, a horizontal tube sheet extending across the vessel, a plurality of U-shaped tubes, having each end secured to and extending through the tube sheet, means for introducing heating fluid to one end of each of the U-shaped tubes, means for removing heating fluid from the other end of each of the U-shaped tubes, tube support means positioned within the vessel for preventing tube vibration, the tube support means including horizontally positioned means closely surrounding, but slightly spaced from each tube, means through which access can be had to the vessel interior beneath the tube sheet when the steam generator is not in operation, and testing means for determining whether or not a tube is locked into a tube support means including a longitudinal member, with a first end located inside the tube to be tested, and a second end located outside of the tube, means for securing the first end of the member to the inside of the tube, means for heating a length of the longitudinal member, and an equal length of the tube, to an elevated temperature, and means for indicating movement of the second end of the longitudinal member away from the tube end, which would indicate that the tube is locked into the support means

  1. Procedure for generating steam and steam generator for operating said procedure

    International Nuclear Information System (INIS)

    Chlique, Bernard.

    1975-01-01

    This invention concerns the generation of steam by bringing the water to be vaporised into indirect thermal exchange relation with the heating steam which condenses when passing in series, along alternate routes, through bundles of tubes immersed in a vaporising chamber. A number of steam generators working on this principle already exist. The purpose of the invention is to modify the operating method of these steam generators by means of a special disposition making it possible to build a compact unit including an additional bundle of tubes heated by the condensates collected at the outlet of each bundle through which the heating steam passes [fr

  2. Electro-oxidation of methanol diffused through proton exchange membrane on Pt surface: crossover rate of methanol

    International Nuclear Information System (INIS)

    Jung, Inhwa; Kim, Doyeon; Yun, Yongsik; Chung, Suengyoung; Lee, Jaeyoung; Tak, Yongsug

    2004-01-01

    Methanol crossover rate through proton exchange membrane (Nafion 117) was investigated with a newly designed electrochemical stripping cell. Nanosize Pt electrode was prepared by the electroless deposition. Distinct electrocatalytic oxidation behaviors of methanol inside membrane were similar to the methanol oxidation in aqueous electrolyte, except adsorption/desorption of hydrogen. The amount of methanol diffused through membrane was calculated from the charge of methanol oxidation during repetitive cyclic voltammetry (CV) and methanol crossover rate was estimated to be 0.69 nmol/s

  3. Design, fabrication and testing of an air-breathing micro direct methanol fuel cell with compound anode flow field

    International Nuclear Information System (INIS)

    Wang, Luwen; Zhang, Yufeng; Zhao, Youran; An, Zijiang; Zhou, Zhiping; Liu, Xiaowei

    2011-01-01

    An air-breathing micro direct methanol fuel cell (μDMFC) with a compound anode flow field structure (composed of the parallel flow field and the perforated flow field) is designed, fabricated and tested. To better analyze the effect of the compound anode flow field on the mass transfer of methanol, the compound flow field with different open ratios (ratio of exposure area to total area) and thicknesses of current collectors is modeled and simulated. Micro process technologies are employed to fabricate the end plates and current collectors. The performances of the μDMFC with a compound anode flow field are measured under various operating parameters. Both the modeled and the experimental results show that, comparing the conventional parallel flow field, the compound one can enhance the mass transfer resistance of methanol from the flow field to the anode diffusion layer. The results also indicate that the μDMFC with an anode open ratio of 40% and a thickness of 300 µm has the optimal performance under the 7 M methanol which is three to four times higher than conventional flow fields. Finally, a 2 h stability test of the μDMFC is performed with a methanol concentration of 7 M and a flow velocity of 0.1 ml min −1 . The results indicate that the μDMFC can work steadily with high methanol concentration.

  4. Experimental analysis of methanol cross-over in a direct methanol fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Casalegno, Andrea [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: andrea.casalegno@polimi.it; Grassini, Paolo [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: PGrassini@seal.it; Marchesi, Renzo [Dipartimento di Energetica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan (Italy)]. E-mail: renzo.marchesi@polimi.it

    2007-03-15

    Methanol cross-over through the polymeric membrane is one of the main causes limiting direct methanol fuel cell performances. It causes fuel wasting and enhances cathode overpotential. A repeatable and reproducible measurement system, that assures the traceability of the measurement to international reference standards, is necessary to compare different fuel cell construction materials. In this work a method to evaluate methanol cross-over rate and operating condition influence is presented and qualified in term of measurement uncertainty. In the investigated range, the methanol cross-over rate results mainly due to diffusion through the membrane, in fact it is strongly affected by temperature. Moreover the cross-over influence on fuel utilization and fuel cell efficiency is investigated. The methanol cross-over rate appears linearly proportional to electrochemical fuel utilization and values, obtained by measurements at different anode flow rate but constant electrochemical fuel utilization, are roughly equal; methanol wasting, due to cross-over, is considerable and can still be higher than electrochemical utilization. The fuel recirculation effect on energy efficiency has been investigated and it was found that fuel recirculation gives more advantage at low temperature, but fuel cell energy efficiency results are in any event higher at high temperature.

  5. Experimental analysis of methanol cross-over in a direct methanol fuel cell

    International Nuclear Information System (INIS)

    Casalegno, Andrea; Grassini, Paolo; Marchesi, Renzo

    2007-01-01

    Methanol cross-over through the polymeric membrane is one of the main causes limiting direct methanol fuel cell performances. It causes fuel wasting and enhances cathode overpotential. A repeatable and reproducible measurement system, that assures the traceability of the measurement to international reference standards, is necessary to compare different fuel cell construction materials. In this work a method to evaluate methanol cross-over rate and operating condition influence is presented and qualified in term of measurement uncertainty. In the investigated range, the methanol cross-over rate results mainly due to diffusion through the membrane, in fact it is strongly affected by temperature. Moreover the cross-over influence on fuel utilization and fuel cell efficiency is investigated. The methanol cross-over rate appears linearly proportional to electrochemical fuel utilization and values, obtained by measurements at different anode flow rate but constant electrochemical fuel utilization, are roughly equal; methanol wasting, due to cross-over, is considerable and can still be higher than electrochemical utilization. The fuel recirculation effect on energy efficiency has been investigated and it was found that fuel recirculation gives more advantage at low temperature, but fuel cell energy efficiency results are in any event higher at high temperature

  6. METHANOL REMOVAL FROM METHANOL-WATER MIXTURE USING ACTIVATED SLUDGE, AIR STRIPPING AND ADSORPTION PROCESS: COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    SALAM K. AL-DAWERY

    2015-12-01

    Full Text Available An experimental research has been carried out in order to examine the removal of methanol from methanol-water mixtures using three different methods; activated sludge; activated carbon and air stripping. The results showed that the methanol was totally consumed by the bacteria as quickly as the feed entered the activated sludge vessel. Air stripping process has a limited ability for removing of methanol due to strong intermolecular forces between methanol and water; however, the results showed that the percentage of methanol removed using air pressure at 0.5 bar was higher than that of using air pressure of 0.25 bar. Removal of methanol from the mixture with a methanol content of 5% using activated carbon was not successful due to the limited capacity of the of the activated carbon. Thus, the activated sludge process can be considered as the most suitable process for the treatment of methanol-water mixtures.

  7. Influence of Boiling, Steaming and Frying of Selected Leafy Vegetables on the In Vitro Anti-inflammation Associated Biological Activities

    Directory of Open Access Journals (Sweden)

    K. D. P. P. Gunathilake

    2018-03-01

    Full Text Available The aim of the present study was to evaluate the effect of cooking (boiling, steaming, and frying on anti-inflammation associated properties in vitro of six popularly consumed green leafy vegetables in Sri Lanka, namely: Centella asiatica, Cassia auriculata, Gymnema lactiferum, Olax zeylanica, Sesbania grnadiflora, and Passiflora edulis. The anti-inflammation associated properties of methanolic extracts of cooked leaves were evaluated using four in vitro biological assays, namely, hemolysis inhibition, proteinase inhibition, protein denaturation inhibition, and lipoxygenase inhibition. Results revealed that the frying of all the tested leafy vegetables had reduced the inhibition abilities of protein denaturation, hemolysis, proteinase, and lipoxygenase activities when compared with other food preparation methods. Steaming significantly increased the protein denaturation and hemolysis inhibition in O. zeylanica and P. edulis. Steaming of leaves increased inhibition activity of protein denaturation in G. lactiferum (by 44.8% and P. edulis (by 44%; hemolysis in C. asiatica, C. auriculata, and S. grandiflora; lipoxygenase inhibition ability in P. edulis (by 50%, C. asiatica (by 400%, and C. auriculata leaves (by 250%; proteinase inhibition in C. auriculata (100% when compared with that of raw leaves. In general, steaming and boiling in contrast to frying protect the health-promoting properties of the leafy vegetables.

  8. Process Technology Development of Ni Electroplating in Steam Generator Tube

    International Nuclear Information System (INIS)

    Kim, Joung Soo; Kim, H. P.; Lim, Y. S.; Kim, S. S.; Hwang, S. S.; Yi, Y. S.; Kim, D. J.; Jeong, M. K.

    2009-11-01

    Operating nuclear power steam generator tubing material, Alloy 600, having superior resistance to corrosion has many experiences of damage by various corrosion mechanisms during long term operation period. In this research project, a new Ni electroplating technology to be applied to repair the damaged steam generator tubes has been developed. In this technology development, the optimum conditions for variables affecting the Ni electroplating process, optimum process conditions for maximum adhesion forces at interface between were established. The various mechanical properties (RT and HT tensile, fatigue, creep, burst, etc.) and corrosion properties (general corrosion, pitting, crevice corrosion, stress corrosion cracking, boric acid corrosion, doped steam) of the Ni plated layers made at the established optimum conditions have been evaluated and confirmed to satisfy the specifications. In addition, a new ECT probe developed at KAERI enable to detect defects from magnetic materials was confirmed to be used for Ni electroplated Alloy 600 tubes at the field. For the application of this developed technology to operating plants, a mock-up electroplating system has been designed and manufactured, and set up at Doosan Heavy Industry Co. and also its performance test has been done. At same time, the anode probe has been modified and improved to be used with the established mock-up system without any problem

  9. Modelling and experimental studies on a direct methanol fuel cell working under low methanol crossover and high methanol concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V.B.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [Instituto Nacional de Energia e Geologia, Fuel Cells and Hydrogen, Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal)

    2009-08-15

    A number of issues need to be resolved before DMFC can be commercially viable such as the methanol crossover and water crossover which must be minimised in portable DMFCs. The main gain of this work is to systematically vary commercial MEA materials and check their influence on the cell performance of a direct methanol fuel cell operating at close to room temperature. A detailed experimental study on the performance of an <> developed DMFC with 25 cm{sup 2} of active membrane area, working near the ambient conditions is described. Tailored MEAs (membrane-electrode assemblies), with different structures and combinations of gas diffusion layers (GDLs), were designed and tested in order to select optimal working conditions at high methanol concentration levels without sacrificing performance. The experimental polarization and power density curves were successfully compared with the predictions of a steady state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC recently developed by the same authors. The influence of the anode gas diffusion layer media, the membrane thickness and the MEA properties on the cell performance are explained under the light of the predicted methanol crossover rate across the membrane. A tailored MEA build-up with the common available commercial materials was proposed to achieve relatively low methanol crossover, operating at high methanol concentrations. The use of adequate materials for the gas diffusion layers (carbon paper at the anode GDL and carbon cloth at the cathode GDL) enables the use of thinner membranes enhancing the water back diffusion which is essential to work at high methanol concentrations. (author)

  10. The progress of SINOPEC methanol-to-olefins (S-MTO) technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongxing; Xie, Zaiku; Zhao, Guoliang [SINOPEC Shanghai Research Institute of Petrochemical Technology (China)

    2013-11-01

    It is widely recognized that naphtha steam crackers and FCC units are the main current sources of ethylene and propylene. On the condition of high oil price, olefin producers are striving to develop new economical routes to produce ethylene and propylene with low-cost feedstocks. Methanol to olefins (MTO) has aroused great attention in recent years, and SINOPEC has developed a new kind of MTO process named S-MTO which features high olefins selectivity, high methanol conversion and low catalyst consumption. Puyang Zhongyuan 200 KTA S-MTO has been in steady operation for more than 17 months. The catalyst used in the process is based on a silicoaluminophosphate, SAPO-34, which has very high carbon selectivity to low carbon olefins. Results from the commercial plant show that S-MTO process converts methanol to ethylene and propylene at about 81% carbon selectivity. The carbon selectivity approaches 92% if butenes are also accounted for as part of the product. Typically, the ratio of propylene to ethylene can range from 0.6 to 1.3. When combined with OCC (Olefin Catalytic Cracking) process to convert the heavier olefins, the overall yield of ethylene and propylene can increase to 85% {proportional_to} 87% and propylene-ethylene ratios of more than 1.5 are achievable. Other co-products include very small amounts of C1-C4 paraffins, hydrogen, CO and CO{sub 2}, as well as heavier oxygenates only with ppm level. Because of the quick deactivation of MTO catalyst, a kind of high efficiency fast fluidized bed reactor is adopted. The activity of deactivated catalyst is recovered by burning the coke in the regenerator. This paper gives an updated introduction of S-MTO technology developed by SINOPEC SRIPT. (orig.)

  11. Process and device for removing sludge deposited on the tube plate of a steam generator

    International Nuclear Information System (INIS)

    Charamathieu, A.; Dessales, J.; Lebouc, B.

    1983-01-01

    To remove the sludges on the tubular plate, one lance, at least, is moved radially from the center of the tubular plate between two rows of tubes, in a parallel direction to the tubular plate and near this one. Two high pressure jets are moved from the extremity of the lance and, in fixed and symmetrical directions about the direction of the rows. The two jets are interrupted when passing in front of the heat exchange tubes of the generator; the cleaning liquid is simultaneously carried off from the periphery of the group of tubes [fr

  12. Sorption phenomena of methanol on heat treated coal; Netsushori wo hodokoshita sekitan no methanol kyuchaku tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, H.; Kaiho, M.; Yamada, O.; Soneda, Y.; Kobayashi, M.; Makino, M. [National Institute for Resources and Environment, Tsukuba (Japan)

    1996-10-28

    Experiments were carried out to learn methanol sorption characteristics of heat-treated coal. When Taiheiyo coal is heat-treated at 125{degree}C, performed with a first methanol adsorption at 25{degree}C, and then desorption at 25{degree}C, a site with strong interaction with methanol and a site with relatively weak interaction are generated in test samples. A small amount of methanol remains in both sites. Then, when the methanol is desorbed at as low temperature as 70{degree}C, the methanol in the site with strong interaction remains as it has existed therein, but the methanol in the site with relatively weak interaction desorbs partially, hence the adsorption amount in a second adsorption at 25{degree}C increases. However, when desorption is performed at as high temperature as 125{degree}C, the methanol in the site with strong interaction also desorbs, resulting in increased adsorption heat in the second adsorption. The adsorption velocity drops, however. Existence of methanol in a site with strong interaction affects the adsorption velocity, but no effect is given by methanol in a site with weak interaction. 3 refs., 4 figs.

  13. Thermal-hydraulic experiments for the PCHE type steam generator

    International Nuclear Information System (INIS)

    Shin, C. W.; No, H. C.

    2015-01-01

    Printed circuit heat exchanger (PCHE) manufactured by HEATRIC is a compact type of the mini-channel heat exchanger. The PCHE is manufactured by diffusion bonding of the chemically-etched plates, and has high heat transfer rate due to a large surface. Therefore, the size of heat exchanger can be reduced by 1/5 - 1/6 and PCHE can be operated under high pressure, high temperature and multi-phase flow. Under such merits, it is used as heat exchanger with various purposes of gas cycle and water cycle. Recently, it is newly suggested as an application of a steam generator. IRIS of MIT and FASES of KAIST conceptually adopted PCHE as a steam generator. When using boiling condition of micro-channel, flow instability is one of the critical issues. Instability may cause unstable mass flow rate, sudden temperature change and system control failure. However instability tests of micro channels using water are very limited because the previous studies were focused on a single tube or other fluid instead of water. In KAIST, we construct the test facility to study the thermal hydraulics and fluid dynamics of the heat exchanger, especially occurrence of instability. By inducing the pressure drop of inlet water, amplitude of oscillation declined by 90%. Finally, the throttling effect was experimentally confirmed that PCHE could be utilized as a steam generator

  14. Experimental studies of PWR vertical steam generator performance

    International Nuclear Information System (INIS)

    Ding Xunshen

    1998-06-01

    The characteristics of heat transfer, natural circulation and moisture separation equipment with a vertical steam generator model are tested on a high-temperature and high-pressure test facility. The primary loop pipe is made of low alloy steel. the primary water at 10.13 MPa is driven by two centrifugal pumps. Boiler is designed to elevate the primary water temperature by 60 degree C at a flow rate of 65 t/h. The test model can produce a maximum steam flow of 8 t/h; 240 stainless steel U tubes are invert connected with the tubesheet, the tube dimensions are φ15 mm x 1.5 mm. The model has a height of 5.789 m. Heat transfer characteristics experiment is obtained: The steam generator thermal design can neglect the existence of preheating region, considering the saturated boiling takes place over all the tube surface. This does not exactly reflect the actual heat transfer coefficient and temperature difference. But, the product of two parameters is lower for design than for experiment so that heat transfer coefficient and temperature difference combine to result in a larger heat transfer area for design than for experiment. Moisture separator is a swirl vane separator. Dryer is a single circle of vertical chevron plate separator. Test results indicate the separation efficiency of the moisture separator and dryer is very satisfactory and the exit moisture is much better than 0.25% (the required content)

  15. A State of the Art Report on Wear Damage of Steam Generator Tubes

    International Nuclear Information System (INIS)

    Lim, Yun Soo; Kim, Joung Soo; Kim, Hong Pyo; Hwang, Seong Sik; Jung, Man Kyo

    2004-10-01

    The recent status on wear damage of steam generator tubes caused by flow-induced vibration was investigated, and the criteria for structural integrity evaluation of the wear-damaged tubes were reviewed. It was surveyed how the wear damage of tubes could be affected by main parameters, such as, materials properties and their combination, impact load and vibration amplitude/frequency, contact areas and diametral clearance between the tube and tube support plate, wear test duration, and test temperature. Finally, corrosive wear, which means the combined action of corrosion and wear simultaneously, was also surveyed in this report. There has been only a few works concerned on the wear damage of steam generator tubes in Korea, compared with the leading foreign research institutes. Especially, the experience related to the wear characteristics of Alloy 690, which has become a replacement material for Alloy 600 as steam generator tubes, is far from satisfactory. Systematic studies, therefore, concerned with structural integrity of tubes as well as improvement of were resistance of Alloy 690 in the PWR environment are needed

  16. The effect of steam separataor efficiency on transient following a steam line break

    International Nuclear Information System (INIS)

    Choi, J.H.; Ohn, M.Y.; Lee, N.H.; Hwang, S.T.; Lee, S.K.

    1996-01-01

    Detailed thermalhydraulic simulations for CANDU 6 steam line break inside containment are performed to predict the response of the primary and secondary circuits. The analysis is performed using the thermalhydraulic computer code, CATHENA, with a coupled primary and secondary circuit model. A two-loop representation of the primary and secondary circuits is modelled. The secondary circuit model includes the feedwater line from the deaerator storage tank, multi-node steam generators and the steam line up to the turbine. Two cases were carried out using different assumptions for the efficiency of the steam separators. Case 1 assumes the efficiency of the steam separators becomes zero when the water level in the steam drum increases to the elevation of primary cyclones, or the outlet flow from the steam generator becomes higher than 150 % of normal flow. Case 2 assumes the efficiency becomes zero only when the water level in the steam drum reaches the elevation of primary cyclones. The simulation results show that system responses are sensitive to the assumption for the efficiency of the steam separators and case 1 gives higher discharge energy. Fuel cooling is assured, since primary circuit is cooled down sufficiently by the steam generators for both cases. (author)

  17. Steam separator-superheater with drawing of a fraction of the dried steam

    International Nuclear Information System (INIS)

    Bessouat, Roger; Marjollet, Jacques.

    1976-01-01

    This invention concerns a vertical separator-superheater of the steam from a high pressure expansion turbine before it is admitted to an expansion turbine at a lower pressure, by heat exchange with steam under a greater pressure, and drawing of a fraction of the dried steam before it is superheated. Such drawing off is necessary in the heat exchange systems of light water nuclear reactors. Its purpose is to provide a separator-superheater that provides an even flow of non superheated steam and a regular distribution of the steam to be superheated to the various superheating bundles, with a significantly uniform temperature of the casing, thereby preventing thermal stresses and ensuring a minimal pressure drop. The vertical separator-superheater of the invention is divided into several vertical sections comprising as from the central area, a separation area of the steam entrained water and a superheater area and at least one other vertical section with only a separation area of the steam entrained water [fr

  18. Dietary methanol and autism.

    Science.gov (United States)

    Walton, Ralph G; Monte, Woodrow C

    2015-10-01

    The authors sought to establish whether maternal dietary methanol during pregnancy was a factor in the etiology of autism spectrum disorders. A seven item questionnaire was given to women who had given birth to at least one child after 1984. The subjects were solicited from a large primary care practice and several internet sites and separated into two groups - mothers who had given birth to a child with autism and those who had not. Average weekly methanol consumption was calculated based on questionnaire responses. 550 questionnaires were completed by women who gave birth to a non-autistic child. On average these women consumed 66.71mg. of methanol weekly. 161 questionnaires were completed by women who had given birth to an autistic child. The average estimated weekly methanol consumption for this group was 142.31mg. Based on the results of the Wilcoxon rank sum-test, we see a significant difference between the reported methanol consumption rates of the two groups. This study suggests that women who have given birth to an autistic child are likely to have had higher intake of dietary sources of methanol than women who have not. Further investigation of a possible link of dietary methanol to autism is clearly warranted. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Antinociceptive properties of the aqueous and methanol extracts of the stem bark of Petersianthus macrocarpus (P. Beauv.) Liben (Lecythidaceae) in mice.

    Science.gov (United States)

    Bomba, Francis Desire Tatsinkou; Wandji, Bibiane Aimee; Piegang, Basile Nganmegne; Awouafack, Maurice Ducret; Sriram, Dharmarajan; Yogeeswari, Perumal; Kamanyi, Albert; Nguelefack, Telesphore Benoit

    2015-11-04

    Aqueous maceration from the stem barks of Petersianthus macrocarpus (P. Beauv.) Liben (Lecythidaceae) is taken orally in the central Africa for the management of various ailments, including pain. This work was carried out to evaluate in mice, the antinociceptive effects of the aqueous and methanol extracts of the stem bark of P. macrocarpus. The chemical composition of the aqueous and methanol extracts prepared as cold macerations was determined by high performance liquid chromatography coupled with mass spectrometry (LCMS). The antinociceptive effects of these extracts administered orally at the doses of 100, 200 and 400 mg/kg were evaluated using behavioral pain model induced by acetic acid, formalin, hot-plate, capsaicin and glutamate. The rotarod test was also performed at the same doses. The oral acute toxicity of both extracts was studied at the doses of 800, 1600, 3200 and 6400 mg/kg in mice. The LCMS analysis revealed the presence of ellagic acid as the major constituent in the methanol extract. Both extracts of P. macrocarpus significantly and dose dependently reduced the time and number of writhing induced by acetic acid. They also significantly inhibited the two phases of formalin-induced pain. These effects were significantly inhibited by a pretreatment with naloxone, except for the analgesic activity of the methanol extract at the earlier phase. In addition, nociception induced by hot plate, intraplantar injection of capsaicin or glutamate was significantly inhibited by both extracts. Acute toxicity test showed no sign of toxicity. These results demonstrate that aqueous and methanol extracts of P. macrocarpus are none toxic substances with good central and peripheral antinociceptive effects that are at least partially due to the presence of ellagic acid. These extracts may induce their antinociceptive effect by interfering with opioid, capsaicin and excitatory amino acid pathways. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Hot new gamble on methanol

    Energy Technology Data Exchange (ETDEWEB)

    Hatton, J.

    1981-10-01

    Methanol from coal, wood, or natural gas is being considered as an extender or an alternative source of gasoline. Firms such as Nova and Celanese are gambling millions on the proposition that methanol is a crucial steppingstone to the fuels and chemicals of the future. With a new process developed by Mobil Oil, methanol from coal could be converted into gasoline. By the 1990s Imperial Oil Ltd. expects there will be at least one methanol plant using Alberta coal. These and other plans by the Alberta and British Columbia governments and by Canadian industry to produce methanol are reported.

  1. Sensing methanol concentration in direct methanol fuel cell with total harmonic distortion: Theory and application

    International Nuclear Information System (INIS)

    Mao Qing; Krewer, Ulrike

    2012-01-01

    The nonlinear frequency response of a direct methanol fuel cell (DMFC) is studied by analyzing the total harmonic distortion (THD) spectra. The dependence of the THD spectra on methanol concentration and methanol oxidation kinetics is investigated by means of both simulation and experiment. Simulation using a continuous stirred tank reactor network model suggests that the methanol concentration profile in the anode has a strong impact on the THD spectra. The experimentally observed nonlinear behavior of the DMFC anode can be qualitatively reproduced with a model containing a three-step methanol oxidation mechanism with Kauranen–Frumkin/Temkin kinetics. Both experiment and simulation results show that THD value has a monotonic correlation with methanol concentration at certain frequencies and its sensitivity to concentration is improved with increased current amplitude. The monotonic relationship enables the THD to sense the methanol concentration level by the DMFC itself, which is of mayor interest for the portable application as an external sensor for the system can be omitted.

  2. Metabolism of methanol in acetogenic bacteria

    International Nuclear Information System (INIS)

    Ivey, D.K.W.

    1987-01-01

    Acetogens can grown on methanol in the presence of a cosubstrate that is more oxidized than methanol. Three mol of acetate is formed from 4 mol methanol and 2 mol CO 2 . One mol of methanol is oxidized to CO 2 . The levels of the tetrahydrofolate enzymes, carbon monoxide dehydrogenase, and corrinoids indicate the presence of the acetyl CoA pathway when growing on methanol. The acetyl-CoA pathway of acetate synthesis as presently understood does not include methanol as a substrate. It is demonstrated that methanol is oxidized to formaldehyde and then to formate by a methanol dehydrogenase. It is also possible that the methyl group of methanol is transferred directly to either a corrinoid-type enzyme, or tetrahydrofolate. When cells of C. thermoautotrophicum are grown on 14 CO 2 , acetate becomes labeled in both carbons with a ratio 14 CH 3 / 14 COOH of 0.7. In addition, methanol gets labeled. When cells are grown on 14 CH 3 OH, label appears in both acetate carbons with a ratio of 3.3, and also appears in CO 2 . Thus methanol is preferentially incorporated into the methyl group of acetate, whereas CO 2 is the preferred source of the carboxyl carbon

  3. Computer calculations of air and steam blowdown suppression

    International Nuclear Information System (INIS)

    Norris, D.M. Jr.; McMaster, W.H.; Landram, C.S.; Quinones, D.F.; Gong, E.Y.; Macken, N.A.

    1980-01-01

    We describe a computer code that combines an Eulerian incompressible-fluid algorithm (SOLA) with a Lagrangian finite-element shell algorithm. The former models the fluid and the latter models the containing structure in an analysis of pressure suppression in boiling-water reactors. The code (PELE-IC) calculates loads and structural response from air blow-down and from the oscillatory condensation of steam bubbles in a water pool. The fluid, structure, and coupling algorithms are tested by recalculating problems that have known analytical solutions, including tank drainage, spherical bubble growth, coupling for circular plates, and submerged cylinder vibration. Code calculations are also compared with the results of small-scale blowdown experiments. (orig.)

  4. The Asian methanol market

    International Nuclear Information System (INIS)

    Nagase, Hideki

    1995-01-01

    For the purpose of this presentation, Asia has been broadly defined as a total of 15 countries, namely Japan, Korea, Taiwan, China, Hong Kong, the Philippines, Thailand, Malaysia, Singapore, Indonesia, Myanmar, India, Vietnam, Australia and New Zealand. In 1994 and the first half of 1995, the methanol industry and its derivative industries experienced hard time, because of extraordinarily high methanol prices. In spite of this circumstance, methanol demand in Asian countries has been growing steadily and remarkably, following Asian high economic growth. Most of this growth in demand has been and will continue to be met by outside supply. However, even with increased import of methanol from outside of Asia, as a result of this growth, Asian trade volume will be much larger in the coming years. Asian countries must turn their collective attention to making logistics and transportation for methanol and its derivatives more efficient in the Asian region to make better use of existing supply resources. The author reviews current economic growth as his main topic, and explains the forecast of the growth of methanol demand and supply in Asian countries in the near future

  5. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

    2014-12-15

    Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

  6. The Methanol Economy Project

    Energy Technology Data Exchange (ETDEWEB)

    Olah, George [Univ. of Southern California, Los Angeles, CA (United States); Prakash, G. K. [Univ. of Southern California, Los Angeles, CA (United States)

    2014-02-01

    The Methanol Economy Project is based on the concept of replacing fossil fuels with methanol generated either from renewable resources or abundant natural (shale) gas. The full methanol cycle was investigated in this project, from production of methanol through bromination of methane, bireforming of methane to syngas, CO2 capture using supported amines, co-electrolysis of CO2 and water to formate and syngas, decomposition of formate to CO2 and H2, and use of formic acid in a direct formic acid fuel cell. Each of these projects achieved milestones and provided new insights into their respective fields.

  7. The testing of a steam-water separating device used for vertical steam generators

    International Nuclear Information System (INIS)

    Ding Xunshen; Cui Baoyuan; Xue Yunkui; Liu Shixun

    1989-01-01

    The air-water screening tests of a steam-water separating device used for vertical steam generators at low pressure are introduced. The article puts emphasis on the qualification test of the steam-water separating device at hot conditions in a high temperature and pressure water test rig. The performance of the comprehensive test of the steam-water separating device indicates that the humidity of the steam at the drier exit is much less than the specified amount of 0.25%

  8. Strategies for steam

    International Nuclear Information System (INIS)

    Hennagir, T.

    1996-01-01

    This article is a review of worldwide developments in the steam turbine and heat recovery steam generator markets. The Far East is driving the market in HRSGs, while China is driving the market in orders placed for steam turbine prime movers. The efforts of several major suppliers are discussed, with brief technical details being provided for several projects

  9. Towards neat methanol operation of direct methanol fuel cells: a novel self-assembled proton exchange membrane.

    Science.gov (United States)

    Li, Jing; Cai, Weiwei; Ma, Liying; Zhang, Yunfeng; Chen, Zhangxian; Cheng, Hansong

    2015-04-18

    We report here a novel proton exchange membrane with remarkably high methanol-permeation resistivity and excellent proton conductivity enabled by carefully designed self-assembled ionic conductive channels. A direct methanol fuel cell utilizing the membrane performs well with a 20 M methanol solution, very close to the concentration of neat methanol.

  10. Endogenous Methanol Regulates Mammalian Gene Activity

    Science.gov (United States)

    Komarova, Tatiana V.; Petrunia, Igor V.; Shindyapina, Anastasia V.; Silachev, Denis N.; Sheshukova, Ekaterina V.; Kiryanov, Gleb I.; Dorokhov, Yuri L.

    2014-01-01

    We recently showed that methanol emitted by wounded plants might function as a signaling molecule for plant-to-plant and plant-to-animal communications. In mammals, methanol is considered a poison because the enzyme alcohol dehydrogenase (ADH) converts methanol into toxic formaldehyde. However, the detection of methanol in the blood and exhaled air of healthy volunteers suggests that methanol may be a chemical with specific functions rather than a metabolic waste product. Using a genome-wide analysis of the mouse brain, we demonstrated that an increase in blood methanol concentration led to a change in the accumulation of mRNAs from genes primarily involved in detoxification processes and regulation of the alcohol/aldehyde dehydrogenases gene cluster. To test the role of ADH in the maintenance of low methanol concentration in the plasma, we used the specific ADH inhibitor 4-methylpyrazole (4-MP) and showed that intraperitoneal administration of 4-MP resulted in a significant increase in the plasma methanol, ethanol and formaldehyde concentrations. Removal of the intestine significantly decreased the rate of methanol addition to the plasma and suggested that the gut flora may be involved in the endogenous production of methanol. ADH in the liver was identified as the main enzyme for metabolizing methanol because an increase in the methanol and ethanol contents in the liver homogenate was observed after 4-MP administration into the portal vein. Liver mRNA quantification showed changes in the accumulation of mRNAs from genes involved in cell signalling and detoxification processes. We hypothesized that endogenous methanol acts as a regulator of homeostasis by controlling the mRNA synthesis. PMID:24587296

  11. Endogenous methanol regulates mammalian gene activity.

    Directory of Open Access Journals (Sweden)

    Tatiana V Komarova

    Full Text Available We recently showed that methanol emitted by wounded plants might function as a signaling molecule for plant-to-plant and plant-to-animal communications. In mammals, methanol is considered a poison because the enzyme alcohol dehydrogenase (ADH converts methanol into toxic formaldehyde. However, the detection of methanol in the blood and exhaled air of healthy volunteers suggests that methanol may be a chemical with specific functions rather than a metabolic waste product. Using a genome-wide analysis of the mouse brain, we demonstrated that an increase in blood methanol concentration led to a change in the accumulation of mRNAs from genes primarily involved in detoxification processes and regulation of the alcohol/aldehyde dehydrogenases gene cluster. To test the role of ADH in the maintenance of low methanol concentration in the plasma, we used the specific ADH inhibitor 4-methylpyrazole (4-MP and showed that intraperitoneal administration of 4-MP resulted in a significant increase in the plasma methanol, ethanol and formaldehyde concentrations. Removal of the intestine significantly decreased the rate of methanol addition to the plasma and suggested that the gut flora may be involved in the endogenous production of methanol. ADH in the liver was identified as the main enzyme for metabolizing methanol because an increase in the methanol and ethanol contents in the liver homogenate was observed after 4-MP administration into the portal vein. Liver mRNA quantification showed changes in the accumulation of mRNAs from genes involved in cell signalling and detoxification processes. We hypothesized that endogenous methanol acts as a regulator of homeostasis by controlling the mRNA synthesis.

  12. Condensation of steam

    International Nuclear Information System (INIS)

    Prisyazhniuk, V.A.

    2002-01-01

    An equation for nucleation kinetics in steam condensation has been derived, the equation taking into account the concurrent and independent functioning of two nucleation mechanisms: the homogeneous one and the heterogeneous one. The equation is a most general-purpose one and includes all the previously known condensation models as special cases. It is shown how the equation can be used in analyzing the process of steam condensation in the condenser of an industrial steam-turbine plant, and in working out new ways of raising the efficiency of the condenser, as well as of the steam-turbine plant as a whole. (orig.)

  13. Developments in the European methanol market

    International Nuclear Information System (INIS)

    Speed, J.

    1995-01-01

    In the late eighties/early nineties the World Methanol Market was basically divided into three regional markets--America, Asia Pacific and Europe. These markets were interrelated but each had its own specific characteristics and traditional suppliers. Now the situation has changed; in the mid nineties there is a Global Methanol Market with global players and effective global pricing and the European market is governed by events world-wide. Europe is however a specific market with specific characteristics which are different from those of other markets although it is also part of the Global Market. Hence before the author focuses on Europe he looks at the World Market. The paper discusses world methanol production and consumption by region, world methanol consumption by end use, world methanol supply demand balance, the west European market, western European methanol production, methanol imports to W. Europe, the Former Soviet Union supplies, W. European methanol consumption by end use, MTBE in Europe, duties on methanol imports into W. Europe, investment in Europe, the effect of the 1994/95 price spike, and key issues for the future of the industry

  14. Experimental evaluation of a Pt based heat exchanger methanol reformer for a HTPEM fuel cell

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2007-01-01

    The storage of hydrogen in hydrogen consuming applications is often inconvenient because of the very low density of hydrogen even at high pressures (0.014 kg/L @ 300 bar) or cryogenically (0.043 kg/L). Much higher volumetric energy densities can be achieved using liquid hydrocarbons as e.g. metha...... (up to 1-2%). This work examines the possibility of using a catalyst coated plate heat exchanger for the reforming process of methanol....

  15. 37 GHz METHANOL MASERS : HORSEMEN OF THE APOCALYPSE FOR THE CLASS II METHANOL MASER PHASE?

    International Nuclear Information System (INIS)

    Ellingsen, S. P.; Breen, S. L.; Sobolev, A. M.; Voronkov, M. A.; Caswell, J. L.; Lo, N.

    2011-01-01

    We report the results of a search for class II methanol masers at 37.7, 38.3, and 38.5 GHz toward a sample of 70 high-mass star formation regions. We primarily searched toward regions known to show emission either from the 107 GHz class II methanol maser transition, or from the 6.035 GHz excited OH transition. We detected maser emission from 13 sources in the 37.7 GHz transition, eight of these being new detections. We detected maser emission from three sources in the 38 GHz transitions, one of which is a new detection. We find that 37.7 GHz methanol masers are only associated with the most luminous 6.7 and 12.2 GHz methanol maser sources, which in turn are hypothesized to be the oldest class II methanol sources. We suggest that the 37.7 GHz methanol masers are associated with a brief evolutionary phase (of 1000-4000 years) prior to the cessation of class II methanol maser activity in the associated high-mass star formation region.

  16. Effect of sorbed methanol, current, and temperature on multicomponent transport in nafion-based direct methanol fuel cells.

    Science.gov (United States)

    Rivera, Harry; Lawton, Jamie S; Budil, David E; Smotkin, Eugene S

    2008-07-24

    The CO2 in the cathode exhaust of a liquid feed direct methanol fuel cell (DMFC) has two sources: methanol diffuses through the membrane electrode assembly (MEA) to the cathode where it is catalytically oxidized to CO2; additionally, a portion of the CO2 produced at the anode diffuses through the MEA to the cathode. The potential-dependent CO2 exhaust from the cathode was monitored by online electrochemical mass spectrometry (ECMS) with air and with H2 at the cathode. The precise determination of the crossover rates of methanol and CO2, enabled by the subtractive normalization of the methanol/air to the methanol/H2 ECMS data, shows that methanol decreases the membrane viscosity and thus increases the diffusion coefficients of sorbed membrane components. The crossover of CO2 initially increases linearly with the Faradaic oxidation of methanol, reaches a temperature-dependent maximum, and then decreases. The membrane viscosity progressively increases as methanol is electrochemically depleted from the anode/electrolyte interface. The crossover maximum occurs when the current dependence of the diffusion coefficients and membrane CO2 solubility dominate over the Faradaic production of CO2. The plasticizing effect of methanol is corroborated by measurements of the rotational diffusion of TEMPONE (2,2,6,6-tetramethyl-4-piperidone N-oxide) spin probe by electron spin resonance spectroscopy. A linear inverse relationship between the methanol crossover rate and current density confirms the absence of methanol electro-osmotic drag at concentrations relevant to operating DMFCs. The purely diffusive transport of methanol is explained in terms of current proton solvation and methanol-water incomplete mixing theories.

  17. An Analysis of Methanol and Hydrogen Production via High-Temperature Electrolysis Using the Sodium Cooled Advanced Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shannon M. Bragg-Sitton; Richard D. Boardman; Robert S. Cherry; Wesley R. Deason; Michael G. McKellar

    2014-03-01

    Integration of an advanced, sodium-cooled fast spectrum reactor into nuclear hybrid energy system (NHES) architectures is the focus of the present study. A techno-economic evaluation of several conceptual system designs was performed for the integration of a sodium-cooled Advanced Fast Reactor (AFR) with the electric grid in conjunction with wind-generated electricity. Cases in which excess thermal and electrical energy would be reapportioned within an integrated energy system to a chemical plant are presented. The process applications evaluated include hydrogen production via high temperature steam electrolysis and methanol production via steam methane reforming to produce carbon monoxide and hydrogen which feed a methanol synthesis reactor. Three power cycles were considered for integration with the AFR, including subcritical and supercritical Rankine cycles and a modified supercritical carbon dioxide modified Brayton cycle. The thermal efficiencies of all of the modeled power conversions units were greater than 40%. A thermal efficiency of 42% was adopted in economic studies because two of the cycles either performed at that level or could potentially do so (subcritical Rankine and S-CO2 Brayton). Each of the evaluated hybrid architectures would be technically feasible but would demonstrate a different internal rate of return (IRR) as a function of multiple parameters; all evaluated configurations showed a positive IRR. As expected, integration of an AFR with a chemical plant increases the IRR when “must-take” wind-generated electricity is added to the energy system. Additional dynamic system analyses are recommended to draw detailed conclusions on the feasibility and economic benefits associated with AFR-hybrid energy system operation.

  18. Study on fuel supplying method and methanol concentration sensor for the high efficient operation of methanol fuel cells. Methanol nenryo denchi no unten ni okeru nenryo kyokyu hoho no kento to methanol nodo sensor no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tsukui, Tsutomu; Doi, Ryota; Yasukawa, Saburo; Kuroda, Osamu [Hirachi, Ltd., Tokyo, (Japan)

    1990-01-20

    A fuel supplying method was studied and demonstrated, essential to the high efficient operation of methanol fuel cells. Methanol and water were supplied independently from each tank to an anordic electrolyte tank in a circulating system, detecting a methanol concentration and liquid level of anordic electrolyte by each sensor, respectively. A methanol sensor was also developed to detect accurately the concentration based on electrochemical reaction under a constant voltage. A detection control circuit was insulated from a constant-voltage power supply to prevent external noises. The methanol sensor output was compensated for temperature, and a new level sensing method was adopted to send out a command comparing different responses to electrolyte shortage. As the methanol fuel cell was operated with this fuel supplying system, the stable characteristics of the cell were obtained within the variation of {plus minus} 0.1mol/l from the specified methanol concentration. 6 refs., 17 figs., 1 tab.

  19. Sensor-less control of the methanol concentration of direct methanol fuel cells at varying ambient temperatures

    International Nuclear Information System (INIS)

    An, Myung-Gi; Mehmood, Asad; Ha, Heung Yong

    2014-01-01

    Highlights: • A new algorithm is proposed for the sensor-less control of methanol concentration. • Two different strategies are used depending on the ambient temperatures. • Energy efficiency of the DMFC system has been improved by using the new algorithm. - Abstract: A new version of an algorithm is used to control the methanol concentration in the feed of DMFC systems without using methanol sensors under varying ambient temperatures. The methanol concentration is controlled indirectly by controlling the temperature of the DMFC stack, which correlates well with the methanol concentration. Depending on the ambient temperature relative to a preset reference temperature, two different strategies are used to control the stack temperature: either reducing the cooling rate of the methanol solution passing through an anode-side heat exchanger; or, lowering the pumping rate of the pure methanol to the depleted feed solution. The feasibility of the algorithm is evaluated using a DMFC system that consists of a 200 W stack and the balance of plant (BOP). The DMFC system includes a sensor-less methanol controller that is operated using a LabView system as the central processing unit. The algorithm is experimentally confirmed to precisely control the methanol concentration and the stack temperature at target values under an environment of varying ambient temperatures

  20. Steam generator

    International Nuclear Information System (INIS)

    Fenet, J.-C.

    1980-01-01

    Steam generator particularly intended for use in the coolant system of a pressurized water reactor for vaporizing a secondary liquid, generally water, by the primary cooling liquid of the reactor and comprising special arrangements for drying the steam before it leaves the generator [fr

  1. Steam generator with perfected dryers

    International Nuclear Information System (INIS)

    Fenet, J.C.

    1987-01-01

    This steam generator has vertically superposed array of steam dryers. These dryers return the steam flow of 180 0 . The return of the water is made by draining channels to the steam production zone [fr

  2. Device for the selective positioning of a component on a tube plate

    International Nuclear Information System (INIS)

    1974-01-01

    The invention relates to a device for the selective positioning of a component on a tube plate. It particularly applies to the positioning of a guide tube head successively opposite all the tubes of the tube bundle of a nuclear reactor steam generator. The large number of tubes in the tube bundle of the steam generator in a pressure water nuclear power station must be checked periodically for any likely corrosion. This check is effected with a Foucault current probe which is inserted in each tube in turn and is connected to a probe signal processing unit. The probe is placed in a flexible guide tube brought in turn in front of each tube of the bundle to be checked. The invention concerns a device to move the opening of a tube guide for a Foucault current detector over the entire surface of the tube plate, thereby providing access to all the tubes whilst limiting the interventions to a single positioning and a single withdrawal of the apparatus for testing all the bundle. Between the two interventions at the beginning and end of the operation, all displacements are remote controlled from outside the dangerous radioacive area [fr

  3. SID seeks sludge and foreign bodies in steam generator upper heads while CECIL robotically removes them

    International Nuclear Information System (INIS)

    Ashton, A.T.; Gay, J.

    1993-01-01

    The CECIL [Consolidated Edison Combined Inspection and Lancing] system provides a range of maintenance tools for cleaning the region between the tubesheet and the first support plate in steam generators. SID [Secondary Inspection Device] extends access to and inspection of the upper bundle region. Work is being done to combine CECIL and SID technology to inspect and hydraulically clean the upper bundle. (Author)

  4. How to compute the power of a steam turbine with condensation, knowing the steam quality of saturated steam in the turbine discharge

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Albarran, Manuel Jaime; Krever, Marcos Paulo Souza [Braskem, Sao Paulo, SP (Brazil)

    2009-07-01

    To compute the power and the thermodynamic performance in a steam turbine with condensation, it is necessary to know the quality of the steam in the turbine discharge and, information of process variables that permit to identifying with high precision the enthalpy of saturated steam. This paper proposes to install an operational device that will expand the steam from high pressure point on the shell turbine to atmosphere, both points with measures of pressure and temperature. Arranging these values on the Mollier chart, it can be know the steam quality value and with this data one can compute the enthalpy value of saturated steam. With the support of this small instrument and using the ASME correlations to determine the equilibrium temperature and knowing the discharge pressure in the inlet of surface condenser, the absolute enthalpy of the steam discharge can be computed with high precision and used to determine the power and thermodynamic efficiency of the turbine. (author)

  5. Generation of gaseous methanol reference standards

    International Nuclear Information System (INIS)

    Geib, R.C.

    1991-01-01

    Methanol has been proposed as an automotive fuel component. Reliable, accurate methanol standards are essential to support widespread monitoring programs. The monitoring programs may include quantification of methanol from tailpipe emissions, evaporative emissions, plus ambient air methanol measurements. This paper will present approaches and results in the author's investigation to develop high accuracy methanol standards. The variables upon which the authors will report results are as follows: (1) stability of methanol gas standards, the studies will focus on preparation requirements and stability results from 10 to 1,000 ppmv; (2) cylinder to instrument delivery system components and purge technique, these studies have dealt with materials in contact with the sample stream plus static versus flow injection; (3) optimization of gas chromatographic analytical system will be discussed; (4) gas chromatography and process analyzer results and utility for methanol analysis will be presented; (5) the accuracy of the methanol standards will be qualified using data from multiple studies including: (a) gravimetric preparation; (b) linearity studies; (c) independent standards sources such as low pressure containers and diffusion tubes. The accuracy will be provided as a propagation of error from multiple sources. The methanol target concentrations will be 10 to 500 ppmv

  6. Vibration Analysis for Steam Dryer of APR1400 Steam Generator

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung-heum; Ko, Doyoung [KHNP CRI, Daejeon (Korea, Republic of); Cho, Minki [Doosan Heavy Industry, Changwon (Korea, Republic of)

    2016-10-15

    This paper is related to comprehensive vibration assessment program for APR1400 steam generator internals. According to U.S. Nuclear Regulatory Commission, Regulatory Guide 1.20 (Rev.3, March 2007), we conducted vibration analysis for a steam dryer as the second steam separator of steam generator internals. The vibration analysis was performed at the 100 % power operating condition as the normal operation condition. The random hydraulic loads were calculated by the computational fluid dynamics and the structural responses were predicted by power spectral density analysis for the probabilistic method. In order to meet the recently revised U.S. NRC RG 1.20 Rev.3, the CVAP against the potential adverse flow effects in APR1400 SG internals should be performed. This study conducted the vibration response analysis for the SG steam dryer as the second moisture separator at the 100% power condition, and evaluated the structural integrity. The predicted alternating stress intensities were evaluated to have more than 17.78 times fatigue margin compared to the endurance limit.

  7. Steam Digest: Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  8. Steam Digest Volume IV

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-07-01

    This edition of the Steam Digest is a compendium of 2003 articles on the technical and financial benefits of steam efficiency, presented by the stakeholders of the U.S. Department of Energy's BestPractices Steam effort.

  9. Methanol from biomass: A technoeconomic analysis

    International Nuclear Information System (INIS)

    Stevens, D.J.

    1991-01-01

    Biomass-derived methanol offers significant potential as an alternative transportation fuel. Methanol is cleaner burning and has a lower flame temperature than gasoline. These characteristics can result in lower carbon monoxide and nitrogen oxide emissions when methanol is used as a fuel. Methanol produced from biomass offers potential advantages over that from other sources. When produced from biomass which is subsequently regrown, methanol does not contribute net emissions of carbon dioxide, a greenhouse gas, to the atmosphere. The introduction of alternative fuels will likely be driven by a number of political and economic decisions. The ability of biomass to compete with other resources will be determined in part by the economics of the production systems. In this paper, recent technoeconomic analyses of biomass-methanol systems are presented. The results are compared with methanol production from coal and natural gas

  10. Selling steam

    International Nuclear Information System (INIS)

    Zimmer, M.J.; Goodwin, L.M.

    1991-01-01

    This article addresses the importance of steam sales contract is in financing cogeneration facilities. The topics of the article include the Public Utility Regulatory Policies Act provisions and how they affect the marketing of steam from qualifying facilities, the independent power producers market shift, and qualifying facility's benefits

  11. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  12. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

    1998-01-01

    Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

  13. Automated analysis technique developed for detection of ODSCC on the tubes of OPR1000 steam generator

    International Nuclear Information System (INIS)

    Kim, In Chul; Nam, Min Woo

    2013-01-01

    A steam generator (SG) tube is an important component of a nuclear power plant (NPP). It works as a pressure boundary between the primary and secondary systems. The integrity of a SG tube can be assessed by an eddy current test every outage. The eddy current technique(adopting a bobbin probe) is currently the main technique used to assess the integrity of the tubing of a steam generator. An eddy current signal analyst for steam generator tubes continuously analyzes data over a given period of time. However, there are possibilities that the analyst conducting the test may get tired and cause mistakes, such as: missing indications or not being able to separate a true defect signal from one that is more complicated. This error could lead to confusion and an improper interpretation of the signal analysis. In order to avoid these possibilities, many countries of opted for automated analyses. Axial ODSCC (outside diameter stress corrosion cracking) defects on the tubes of OPR1000 steam generators have been found on the tube that are in contract with tube support plates. In this study, automated analysis software called CDS (computer data screening) made by Zetec was used. This paper will discuss the results of introducing an automated analysis system for an axial ODSCC on the tubes of an OPR1000 steam generator.

  14. Methanol as an energy carrier

    Energy Technology Data Exchange (ETDEWEB)

    Biedermann, P.; Grube, T.; Hoehlein, B. (eds.)

    2006-07-01

    For the future, a strongly growing energy demand is expected in the transport sector worldwide. Economically efficient oil production will run through a maximum in the next decade. Higher fuel prices and an environmentally desirable reduction of emissions will increase the pressure for reducing fuel consumption and emissions in road traffic. These criteria show the urgent necessity of structural changes in the fuel market. Due to its advantages concerning industrial-scale production, storage and global availability, methanol has the short- to medium-term potential for gaining increased significance as a substitution product in the energy market. Methanol can be produced both from fossil energy sources and from biomass or waste materials through the process steps of synthesis gas generation with subsequent methanol synthesis. Methanol has the potential to be used in an environmentally friendly manner in gasoline/methanol mixtures for flexible fuel vehicles with internal combustion engines and in diesel engines with pure methanol. Furthermore, it can be used in fuel cell vehicles with on-board hydrogen production in direct methanol fuel cell drives, and in stationary systems for electricity and heat generation as well as for hydrogen production. Finally, in portable applications it serves as an energy carrier for electric power generation. In this book, the processes for the production and use of methanol are presented and evaluated, markets and future options are discussed and issues of safety and environmental impacts are addressed by a team of well-known authors. (orig.)

  15. Pressure drop, steam content and turbulent cross exchange in water/steam flows

    International Nuclear Information System (INIS)

    Teichel, H.

    1978-01-01

    For describing the behaviour of two-phase flows of water and steam with the help of calculating patterns, a number of empirical correlations are required. - In this article, correlations for the friction pressure drop in water/steam flows are compared, as well as for the steam mass and the volumetric steam content with each other and with the test results on simple geometries. As the mutual effect between cooling chanels plays an important part at the longitudinal flow through bar bundles, the appertaining equations are evaluated, in addition. (orig.) 891 HP [de

  16. Ontario hydro development program for steam generator waterlancing applications

    International Nuclear Information System (INIS)

    Malaugh, J.

    1992-01-01

    In the early 1980s, Ontario Hydro's main focus on waterlancing applications was in the development of technology for cleaning tubesheet sludge piles. In 1988, when Unit 2 at the Bruce Nuclear Generating Station (BNGS) was derated to 70% of full power due to severely blocked broach plates, high pressure waterlancing was proposed as a short-term solution. Due to the tight geometry that exist in the BNGS SGs (Steam Generator), an innovative approach was needed to deliver high pressure water to the broach hole locations. The initial lances and guides were modelled after a fiber-optic inspection system used for visual measurements of the broach openings. The waterlancing technology that was first developed for cleaning BNGS Unit 2 has evolved considerably since 1988. Both Units 1 and 2 upper broach plates have been successfully cleaned by waterlancing. At Pickering NGS, this technology is being further developed for use in cleaning broach plates and for tubesheet sludge lancing. This paper describes the development of the waterlance from the initial low pressure stainless steel lances to the current high pressure 'kevlar' lances. The major advances in this technology were borne out of a need to overcome the challenges presented by the SG geometry restrictions and the tenacity of the deposits that were encountered

  17. Evaluation of the Analgesic Activity of the Methanolic Stem Bark Extract of Dialium Guineense (Wild)

    OpenAIRE

    Ezeja, MI; Omeh, YS; Ezeigbo, II; Ekechukwu, A

    2011-01-01

    Background: Dialium guineense is a medicinal plant used by some communities of Enugu-Ezike in Enugu State, Nigeria for treatment of fever, headache and other diverse ailments. Objectives: The present study evaluated the analgesic activity of the methanolic stem bark extract of the plant. Method: Acetic acid-induced abdominal constriction or writhing, tail immersion and hot plate analgesic models in albino Wistar mice were used for the study. Three test doses (250, 500, 1000 mg/kg body weight)...

  18. What is geothermal steam worth?

    International Nuclear Information System (INIS)

    Thorhallsson, S.; Ragnarsson, A.

    1992-01-01

    Geothermal steam is obtained from high-temperature boreholes, either directly from the reservoir or by flashing. The value of geothermal steam is similar to that of steam produced in boilers and lies in its ability to do work in heat engines such as turbines and to supply heat for a wide range of uses. In isolated cases the steam can be used as a source of chemicals, for example the production of carbon dioxide. Once the saturated steam has been separated from the water, it can be transported without further treatment to the end user. There are several constraints on its use set by the temperature of the reservoir and the chemical composition of the reservoir fluid. These constraints are described (temperature of steam, scaling in water phase, gas content of steam, well output) as are the methods that have been adopted to utilize this source of energy successfully. Steam can only be transported over relatively short distances (a few km) and thus has to be used close to the source. Examples are given of the pressure drop and sizing of steam mains for pipelines. The path of the steam from the reservoir to the end user is traced and typical cost figures given for each part of the system. The production cost of geothermal steam is estimated and its sensitivity to site-specific conditions discussed. Optimum energy recovery and efficiency is important as is optimizing costs. The paper will treat the steam supply system as a whole, from the reservoir to the end user, and give examples of how the site-specific conditions and system design have an influence on what geothermal steam is worth from the technical and economic points of view

  19. Design, fabrication and performance evaluation of an integrated reformed methanol fuel cell for portable use

    Science.gov (United States)

    Zhang, Shubin; Zhang, Yufeng; Chen, Junyu; Yin, Congwen; Liu, Xiaowei

    2018-06-01

    In this paper, an integrated reformed methanol fuel cell (RMFC) as a portable power source is designed, fabricated and tested. The RMFC consists of a methanol steam reformer (MSR), a high temperature proton exchange membrane fuel cell (HT-PEMFC) stack, a microcontroller unit (MCU) and other auxiliaries. First, a system model based on Matlab/Simulink is established to investigate the mass and energy transport characteristics within the whole system. The simulation results suggest a hydrogen flow rate of at least 670 sccm is needed for the system to output 30 W and simultaneously maintain thermal equilibrium. Second, a metallic MSR and an HT-PEMFC stack with 12 cells are fabricated and tested. The tests show that the RMFC system is able to function normally when the performances of all the components meet the minimum requirements. At last, in the experiment of successfully powering a laptop, the RMFC system exhibits a stable performance during the complete work flow of all the phases, namely start-up, output and shutdown. Moreover, with a conservative design of 20 W power rating, maximum energy conversion efficiency of the RMFC system can be achieved (36%), and good stability in long-term operation is shown.

  20. Operation characteristic analysis of a direct methanol fuel cell system using the methanol sensor-less control method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Chang, C.L. [Institute of Nuclear Energy Research (INER), Longtan Township, Taoyuan County (China); Sung, C.C. [National Taiwan University (China)

    2012-10-15

    The application of methanol sensor-less control in a direct methanol fuel cell (DMFC) system eliminates most of the problems encountered when using a methanol sensor and is one of the major solutions currently used in commercial DMFCs. This study focuses on analyzing the effect of the operating characteristics of a DMFC system on its performance under the methanol sensor-less control as developed by Institute of Nuclear Energy Research (INER). Notably, the influence of the dispersion of the methanol injected on the behavior of the system is investigated systematically. In addition, the mechanism of the methanol sensor-less control is investigated by varying factors such as the timing of the injection of methanol, the cathode flow rate, and the anode inlet temperature. These results not only provide insight into the mechanism of methanol sensor-less control but can also aid in the improvement and application of DMFC systems in portable and low-power transportation. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Study of SI engine fueled with methanol vapor and dissociation gas based on exhaust heat dissociating methanol

    International Nuclear Information System (INIS)

    Fu, Jianqin; Deng, Banglin; Liu, Jingping; Wang, Linjun; Xu, Zhengxin; Yang, Jing; Shu, Gequn

    2014-01-01

    Highlights: • The full load power decreases successively from gasoline engine, methanol vapor engine to dissociated methanol engine. • Both power and thermal efficiency of dissociated methanol engine can be improved by boosting pressure. • The conversion efficiency of recovered exhaust gas energy is largely influenced by the BMEP. • At the same BMEP, dissociated methanol engine has higher thermal efficiency than methanol vapor engine and gasoline engine. - Abstract: To improve the fuel efficiency of internal combustion (IC) engine and also achieve the goal of direct usage of methanol fuel on IC engine, an approach of exhaust heat dissociating methanol was investigated, which is a kind of method for IC engine exhaust heat recovery (EHR). A bottom cycle system is coupled with the IC engine exhaust system, which uses the exhaust heat to evaporate and dissociate methanol in its catalytic cracker. The methanol dissociation gas (including methanol vapor) is used as the fuel for IC engine. This approach was applied to both naturally aspirated (NA) engine and turbocharged engine, and the engine performance parameters were predicted by the software GT-power under various kinds of operating conditions. The improvement to IC engine performance and the conversion efficiency of recovered exhaust gas energy can be evaluated by comparing the performances of IC engine fueled with various kinds of fuels (or their compositions). Results show that, from gasoline engine, methanol vapor engine to dissociated methanol engine, the full load power decreases successively in the entire speed area due to the declining of volumetric efficiency, while it is contrary in the thermal efficiency at the same brake mean effective pressure (BMEP) level because of the improving of fuel heating value. With the increase of BMEP, the conversion efficiency of recovered exhaust gas energy is promoted. All those results indicate that the approach of exhaust heat dissociating methanol has large

  2. Modifications for use of methanol or methanol-gasoline blends in automotive vehicles, September 1976-January 1980

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, D.J.; Bolt, J.A.; Cole, D.E.

    1980-01-01

    Methanol or blends of methanol and gasoline as automotive fuels may be attractive means for extending the nation's petroleum reserves. The present study was aimed at identifying potential problems and solutions for this use of methanol. Retrofitting of existing vehicles as well as future vehicle design have been considered. The use of ethanol or higher alcohols was not addressed in this study but will be included at a later date. Several potentially serious problems have been identified with methanol use. The most attractive solutions depend upon an integrated combination of vehicle modifications and fuel design. No vehicle problems were found which could not be solved with relatively minor developments of existing technology providing the methanol or blend fuel was itself engineered to ameliorate the solution. Research needs have been identified in the areas of lubrication and materials. These, while apparently solvable, must precede use of methanol or methanol-gasoline blends as motor fuels. Because of the substantial costs and complexities of a retrofitting program, use of methanol must be evaluated in relation to other petroleum-saving alternatives. Future vehicles can be designed initially to operate satisfactorily on these alternate fuels. However a specific fuel composition must be specified around which the future engines and vehicles can be designed.

  3. Experimental and Numerical Evaluation of the By-Pass Flow in a Catalytic Plate Reactor for Hydrogen Production

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2011-01-01

    Numerical and experimental study is performed to evaluate the reactant by-pass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. By-pass of unconverted methane is evaluated under different wire mesh catalyst width to reactor...

  4. Thermodynamics of R-(+)-2-(4-Hydroxyphenoxy)propanoic Acid Dissolution in Methanol, Ethanol, and Methanol-Ethanol Mixture

    Science.gov (United States)

    Liu, Wei; Ma, Jinju; Yao, Xinding; Fang, Ruina; Cheng, Liang

    2018-05-01

    The solubilities of R-(+)-2-(4-hydroxyphenoxy)propanoic acid (D-HPPA) in methanol, ethanol and various methanol-ethanol mixtures are determined in the temperature range from 273.15 to 323.15 K at atmospheric pressure using a laser detecting system. The solubilities of D-HPPA increase with increasing mole fraction of ethanol in the methanol-ethanol mixtures. Experimental data were correlated with Buchowski-Ksiazczak λ h equation and modified Apelblat equation; the first one gives better approximation for the experimental results. The enthalpy, entropy and Gibbs free energy of D-HPPA dissolution in methanol, ethanol and methanol-ethanol mixtures were also calculated from the solubility data.

  5. Steam Digest 2001

    Energy Technology Data Exchange (ETDEWEB)

    2002-01-01

    Steam Digest 2001 chronicles BestPractices Program's contributions to the industrial trade press for 2001, and presents articles that cover technical, financial and managerial aspects of steam optimization.

  6. Underclad crack development of steam generators tube sheets and reactor vessels nozzles in PWR plants

    International Nuclear Information System (INIS)

    Faure, F.; Bocquet, P.; Boudot, R.; Zacharie, G.

    1985-01-01

    Defects formed, before stress relieving treatment, under the coating of tube plates of steam generators and vessel pipes are cold cracks formed in the segregation zone during surface coating without pre- and postheating of the 2nd layers and eventually of the following coating layers. To solve this problem, the conditions of pre- and post-heating are reinforced and applied to all the coating layers. 13 refs [fr

  7. Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT)

    Energy Technology Data Exchange (ETDEWEB)

    Conocophillips

    2007-09-30

    The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project was established to evaluate integrated electrical power generation and methanol production through clean coal technologies. The project was under the leadership of ConocoPhillips Company (COP), after it acquired Gasification Engineering Corporation (GEC) and the E-Gas gasification technology from Global Energy Inc. in July 2003. The project has completed both Phase 1 and Phase 2 of development. The two project phases include the following: (1) Feasibility study and conceptual design for an integrated demonstration facility at SG Solutions LLC (SGS), previously the Wabash River Energy Limited, Gasification Facility located in West Terre Haute, Indiana, and for a fence-line commercial embodiment plant (CEP) operated at the Dow Chemical Company or Dow Corning Corporation chemical plant locations. (2) Research, development, and testing (RD&T) to define any technology gaps or critical design and integration issues. Phase 1 of this project was supported by a multi-industry team consisting of Air Products and Chemicals, Inc., The Dow Chemical Company, Dow Corning Corporation, Methanex Corporation, and Siemens Westinghouse Power Corporation, while Phase 2 was supported by Gas Technology Institute, TDA Research Inc., and Nucon International, Inc. The SGS integrated gasification combined cycle (IGCC) facility was designed, constructed, and operated under a project selected and co-funded under the Round IV of the United States Department of Energy's (DOE's) Clean Coal Technology Program. In this project, coal and/or other carbonaceous fuel feedstocks are gasified in an oxygen-blown, entrained-flow gasifier with continuous slag removal and a dry particulate removal system. The resulting product synthesis gas (syngas) is used to fuel a combustion turbine generator whose exhaust is integrated with a heat recovery steam generator to drive a refurbished steam turbine

  8. Development of integral type forgings for steam generator of nuclear power plant

    International Nuclear Information System (INIS)

    Suzuki, Komei; Sato, Ikuo; Murai, Etsuo

    1992-01-01

    The use of integral type steel forgings for the construction of pressure vessel enhances the structural integrity of components and makes the fabrication of components and the execution of in-service inspection (ISI) easier than those fabrication from plate and casting materials. Such steel forgings have been realized for steam generator (SG) for nuclear power plant as follows : (1) Forged shell ring : change from welding fabrication of formed plates to forging ; (2) Forged conical shell ring : ditto ; (3) Forged head integral with nozzles (s) : (i) Primary head : change from casting to forging ; (ii) Secondary head : change from welding fabrication of formed plates to forging. These steel forgings have been realized by recent development in manufacturing technologies, such as steel making, forging processes and heat treatment which are vital to the quality of steel forgings. Some examples of recent typical high quality steel forgings developed by the Japan Steel Works, Ltd. (JSW) are introduced, and the main points of the manufacturing technique and the quality attained are also described. (author)

  9. Soil and groundwater remediation guidelines for methanol

    International Nuclear Information System (INIS)

    2010-12-01

    Methanol is used by oil and gas operators to inhibit hydrate formation in the recovery of heavy oils, in natural gas production and transport, as well as in various other production applications. Emissions from methanol primary occur from miscellaneous solvent usage, methanol production, end-product manufacturing, and storage and handling losses. This document provided soil and groundwater remediation guidelines for methanol releases into the environment. The guidelines were consistent with the Alberta Environment tier 1 soil and groundwater framework. The chemical and physical properties of methanol were reviewed. The environmental fate and behavior of methanol releases was discussed, and the behaviour and effects of methanol in terrestrial and aquatic biota were evaluated. The toxicity of methanol and its effects in humans and mammalian species were reviewed. Soil quality and ground water quality guidelines were presented. Surface water and soil guideline calculation methods were provided, and ecological exposure and ground water pathways were discussed. Management limits for methanol concentrations were also provided. 162 refs., 18 tabs., 4 figs.

  10. Triboluminescence and associated decomposition of solid methanol

    International Nuclear Information System (INIS)

    Trout, G.J.; Moore, D.E.; Hawke, J.G.

    1975-01-01

    The decomposition is initiated by the cooling of solid methanol through the β → α transiRon at 157.8K, producing the gases hydrogen, carbon monoxide, and methane. The passage through this lambda transition causes the breakup of large crystals of β-methanol into crystallites of α-methanol and is accompanied by light emission as well as decomposition. This triboluminescence is accompanied by, and apparently produced by, electrical discharges through methanol vapor in the vicinity of the solid. The potential differences needed to produce the electrical breakdown of the methanol vapor apparently arise from the disruption of the long hydrogen bonded chains of methanol molecules present in crystalline methanol. Charge separation following crystal deformation is a characteristic of substances which exhibit gas discharge triboluminescence; solid methanol has been found to emit such luminescence when mechanically deformed in the absence of the β → α transition The decomposition products are not produced directly by the breaking up of the solid methanol but from the vapor phase methanol by the electrical discharges. That gas phase decomposition does occur was confirmed by observing that the vapors of C 2 H 5 OH, CH 3 OD, and CD 3 OD decompose on being admitted to a vessel containing methanol undergoing the β → α phase transition. (U.S.)

  11. A three-dimensional laboratory steam injection model allowing in situ saturation measurements. [Comparing steam injection and steam foam injection with nitrogen and without nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Demiral, B.M.R.; Pettit, P.A.; Castanier, L.M.; Brigham, W.E.

    1992-08-01

    The CT imaging technique together with temperature and pressure measurements were used to follow the steam propagation during steam and steam foam injection experiments in a three dimensional laboratory steam injection model. The advantages and disadvantages of different geometries were examined to find out which could best represent radial and gravity override flows and also fit the dimensions of the scanning field of the CT scanner. During experiments, steam was injected continuously at a constant rate into the water saturated model and CT scans were taken at six different cross sections of the model. Pressure and temperature data were collected with time at three different levels in the model. During steam injection experiments, the saturations obtained by CT matched well with the temperature data. That is, the steam override as observed by temperature data was also clearly seen on the CT pictures. During the runs where foam was present, the saturation distributions obtained from CT pictures showed a piston like displacement. However, the temperature distributions were different depending on the type of steam foam process used. The results clearly show that the pressure/temperature data alone are not sufficient to study steam foam in the presence of non-condensible gas.

  12. Sodium and steam leak simulation studies for fluidized bed steam generators

    International Nuclear Information System (INIS)

    Keeton, A.R.; Vaux, W.G.; Lee, P.K.; Witkowski, R.E.

    1976-01-01

    An experimental program is described which was conducted to study the effects of sodium or steam leaking into an operating fluidized bed of metal or ceramic particles at 680 to 800 0 K. This effort was part of the early development studies for a fluidized-bed steam generator concept using helium as the fluidizing gas. Test results indicated that steam and small sodium leaks had no effect on the quality of fluidization, heat transfer coefficient, temperature distribution, or fluidizing gas pressure drop across the bed. Large sodium leaks, however, immediately upset the operation of the fluidized bed. Both steam and sodium leaks were detected positively and rapidly at an early stage of a leak by instruments specifically selected to accomplish this

  13. DEMONSTRATION BULLETIN STEAM ENHANCED REMEDIATION STEAM TECH ENVIRONMENTAL SERVICES, INC.

    Science.gov (United States)

    Steam Enhanced Remediation is a process in which steam is injected into the subsurface to recover volatile and semivolatile organic contaminants. It has been applied successfully to recover contaminants from soil and aquifers and at a fractured granite site. This SITE demonstra...

  14. A comparison of hydrogen, methanol and gasoline as fuels for fuel cell vehicles: implications for vehicle design and infrastructure development

    Science.gov (United States)

    Ogden, Joan M.; Steinbugler, Margaret M.; Kreutz, Thomas G.

    All fuel cells currently being developed for near term use in electric vehicles require hydrogen as a fuel. Hydrogen can be stored directly or produced onboard the vehicle by reforming methanol, or hydrocarbon fuels derived from crude oil (e.g., gasoline, diesel, or middle distillates). The vehicle design is simpler with direct hydrogen storage, but requires developing a more complex refueling infrastructure. In this paper, we present modeling results comparing three leading options for fuel storage onboard fuel cell vehicles: (a) compressed gas hydrogen storage, (b) onboard steam reforming of methanol, (c) onboard partial oxidation (POX) of hydrocarbon fuels derived from crude oil. We have developed a fuel cell vehicle model, including detailed models of onboard fuel processors. This allows us to compare the vehicle performance, fuel economy, weight, and cost for various vehicle parameters, fuel storage choices and driving cycles. The infrastructure requirements are also compared for gaseous hydrogen, methanol and gasoline, including the added costs of fuel production, storage, distribution and refueling stations. The delivered fuel cost, total lifecycle cost of transportation, and capital cost of infrastructure development are estimated for each alternative. Considering both vehicle and infrastructure issues, possible fuel strategies leading to the commercialization of fuel cell vehicles are discussed.

  15. Steam generator life management

    International Nuclear Information System (INIS)

    Tapping, R.L.; Nickerson, J.; Spekkens, P.; Maruska, C.

    1998-01-01

    Steam generators are a critical component of a nuclear power reactor, and can contribute significantly to station unavailability, as has been amply demonstrated in Pressurized Water Reactors (PWRs). CANDU steam generators are not immune to steam generator degradation, and the variety of CANDU steam generator designs and tube materials has led to some unexpected challenges. However, aggressive remedial actions, and careful proactive maintenance activities, have led to a decrease in steam generator-related station unavailability of Canadian CANDUs. AECL and the CANDU utilities have defined programs that will enable existing or new steam generators to operate effectively for 40 years. Research and development work covers corrosion and mechanical degradation of tube bundles and internals, chemistry, thermal hydraulics, fouling, inspection and cleaning, as well as provision for specially tool development for specific problem solving. A major driving force is development of CANDU-specific fitness-for-service guidelines, including appropriate inspection and monitoring technology to measure steam generator condition. Longer-range work focuses on development of intelligent on-line monitoring for the feedwater system and steam generator. New designs have reduced risk of corrosion and fouling, are more easily inspected and cleaned, and are less susceptible to mechanical damage. The Canadian CANDU utilities have developed programs for remedial actions to combat degradation of performance (Gentilly-2, Point Lepreau, Bruce A/B, Pickering A/B), and have developed strategic plans to ensure that good future operation is ensured. This report shows how recent advances in cleaning technology are integrated into a life management strategy, discusses downcomer flow measurement as a means of monitoring steam generator condition, and describes recent advances in hideout return as a life management tool. The research and development program, as well as operating experience, has identified

  16. Experimental Investigation of a Direct Methanol Fuel Cell with Hilbert Fractal Current Collectors

    Directory of Open Access Journals (Sweden)

    Jing-Yi Chang

    2014-01-01

    Full Text Available The Hilbert curve is a continuous type of fractal space-filling curve. This fractal curve visits every point in a square grid with a size of 2×2, 4×4, or any other power of two. This paper presents Hilbert fractal curve application to direct methanol fuel cell (DMFC current collectors. The current collectors are carved following first, second, and third order Hilbert fractal curves. These curves give the current collectors different free open ratios and opening perimeters. We conducted an experimental investigation into DMFC performance as a function of the free open ratio and opening perimeter on the bipolar plates. Nyquist plots of the bipolar plates are made and compared using electrochemical impedance spectroscopy (EIS experiments to understand the phenomena in depth. The results obtained in this paper could be a good reference for future current collector design.

  17. Steam generator tube failures

    International Nuclear Information System (INIS)

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service

  18. Future steam generator designs. Single wall designs

    International Nuclear Information System (INIS)

    Hayden, O.

    1978-01-01

    to be cut off and only extremely limited and difficult access to the tube plate can be obtained. Thus, for the replacement PFR superheater and reheater now in production, design changes have been introduced which improve the facilities for inspection, improve the engineering integrity of the sodium/water boundary and will enable NPC to prove the new units under real power station operating conditions. The CDFR design is a scaled up replica of the replacement Units and we, therefore, hope to validate the CDFR design by the successful operation in PFR of the new prototype units some time during 1981. It is worthwhile to comment upon the potential advantages of the gas space' requirement in the PFR type of removable 'U' tube. With regard to sodium/water reaction events in the high risk area of the PFR Steam Generators has proved to be in the tube to tube sheet welds and it is fortuitous that the provision of a sodium side gas space enables the designer to incorporate a highly sensitive leak detection system, with a large 'window of protection' value for the monitoring of the critical weld feature. Thus, if the operator wishes, he can lower the level of the sodium during leak location operations and convert what would be a more onerous under-sodium leak into a gas space. leak. If any opening up operations are required, then this could be of some advantage. Design changes from PFR to CDFR as incorporated into the prototype replacement steam generators are shown

  19. Future steam generator designs. Single wall designs

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, O [Nuclear Power Company Ltd, Warrington, Cheshire (United Kingdom)

    1978-10-01

    to be cut off and only extremely limited and difficult access to the tube plate can be obtained. Thus, for the replacement PFR superheater and reheater now in production, design changes have been introduced which improve the facilities for inspection, improve the engineering integrity of the sodium/water boundary and will enable NPC to prove the new units under real power station operating conditions. The CDFR design is a scaled up replica of the replacement Units and we, therefore, hope to validate the CDFR design by the successful operation in PFR of the new prototype units some time during 1981. It is worthwhile to comment upon the potential advantages of the gas space' requirement in the PFR type of removable 'U' tube. With regard to sodium/water reaction events in the high risk area of the PFR Steam Generators has proved to be in the tube to tube sheet welds and it is fortuitous that the provision of a sodium side gas space enables the designer to incorporate a highly sensitive leak detection system, with a large 'window of protection' value for the monitoring of the critical weld feature. Thus, if the operator wishes, he can lower the level of the sodium during leak location operations and convert what would be a more onerous under-sodium leak into a gas space. leak. If any opening up operations are required, then this could be of some advantage. Design changes from PFR to CDFR as incorporated into the prototype replacement steam generators are shown.

  20. Chemical cleaning of the Bruce A steam generators

    International Nuclear Information System (INIS)

    Le Surf, J.E.; Mason, J.B.; Symmons, W.R.; Yee, F.

    1992-01-01

    Deposits consisting mostly of oxides and salts and copper metal in the secondary side of the steam generators at the Bruce A Nuclear Generating Station have caused instability in the steam flow and loss of heat capacity, resulting in derating of the units and reduction in power production. Attempts to remove the deposits by pressure pulsing were unsuccessful. Water lancing succeeded in restoring stability, but restrictions on access prevented complete lancing of the tube support plate holes. Chemical cleaning using a modified EPRI-SGOG process has been selected as the best method of removing the deposits. A complete chemical cleaning system has been designed and fabricated for Ontario Hydro by Pacific Nuclear, with support from AECL CANDU and their suppliers. The system consists of self contained modules which are easily interconnected on site. The whole process is controlled from the Control Module, where all parameters are monitored on a computer video screen. The operator can control motorized valves, pumps and heaters from the computer key board. This system incorporates all the advanced technologies and design features that have been developed by Pacific Nuclear in the design, fabrication and operation of many systems for chemical decontamination and cleaning of nuclear systems. 2 figs

  1. Steam generators, turbines, and condensers. Volume six

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)

  2. Horizontal steam generator thermal-hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Ubra, O. [SKODA Praha Company, Prague (Czechoslovakia); Doubek, M. [Czech Technical Univ., Prague (Czechoslovakia)

    1995-09-01

    Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. The 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.

  3. Enhancement of enzymatic saccharification of Eucalyptus globulus: steam explosion versus steam treatment.

    Science.gov (United States)

    Martin-Sampedro, Raquel; Revilla, Esteban; Villar, Juan C; Eugenio, Maria E

    2014-09-01

    Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition: steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3 min, at 183°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Drying studies of simulated DOE aluminum plate fuels

    International Nuclear Information System (INIS)

    Lords, R.E.; Windes, W.E.; Crepeau, J.C.; Sidwell, R.W.

    1996-01-01

    Experiments have been conducted to validate the Idaho National Engineering Laboratory (INEL) drying procedures for preparation of corroded aluminum plate fuel for dry storage in an existing vented (and filtered) fuel storage facility. A mixture of hydrated aluminum oxide bound with a clay was used to model the aluminum corrosion product and sediment expected in these Department of Energy (DOE) owned fuel types. Previous studies demonstrated that the current drying procedures are adequate for removal of free water inside the storage canister and for transfer of this fuel to a vented dry storage facility. However, using these same drying procedures, the simulated corrosion product was found to be difficult to dry completely from between the aluminum clad plates of the fuel. Another related set of experiments was designed to ensure that the fuel would not be damaged during the drying process. Aluminum plate fuels are susceptible to pitting damage on the cladding that can result in a portion of UAl x fuel meat being disgorged. This would leave a water-filled void beneath the pit in the cladding. The question was whether bursting would occur when water in the void flashes to steam, causing separation of the cladding from the fuel, and/or possible rupture. Aluminum coupons were fabricated to model damaged fuel plates. These coupons do not rupture or sustain any visible damage during credible drying scenarios

  5. Steam and sodium leak simulation in a fluidized-bed steam generator

    International Nuclear Information System (INIS)

    Vaux, W.G.; Keeton, A.R.; Keairns, D.L.

    1977-01-01

    A fluidized-bed steam generator for the liquid metal fast breeder reactor enhances plant availability and minimizes the probability of a water/sodium reaction. An experimental test program was conceived to assess design criteria and fluidized-bed operation under conditions of water, steam, and sodium leaks. Sodium, steam, and water were leaked into helium-fluidized beds of metal and ceramic particles at 900 F. Test results show the effects of leaks on the heat transfer coefficient, quality of fluidization, leak detection, and cleanup procedures

  6. Eddy Current Signature Classification of Steam Generator Tube Defects Using A Learning Vector Quantization Neural Network

    International Nuclear Information System (INIS)

    Garcia, Gabe V.

    2005-01-01

    A major cause of failure in nuclear steam generators is degradation of their tubes. Although seven primary defect categories exist, one of the principal causes of tube failure is intergranular attack/stress corrosion cracking (IGA/SCC). This type of defect usually begins on the secondary side surface of the tubes and propagates both inwards and laterally. In many cases this defect is found at or near the tube support plates

  7. Design of SMART steam generator cassette

    International Nuclear Information System (INIS)

    Kim, Y. W.; Kim, J. I.; Jang, M. H.

    2001-01-01

    Basic design development for the steam generator to be installed in the integral reactor SMART has been performed. Optimization of the steam generator shape, determination of the basic dimension and confirmation of the structural strength have been carried out. Individual steam generator cassette can be replaced in the optimized design concept of steam generator. Shape design of the steam generator cassette has been done on the computer based on 3-D CAE strategy. The structural integrity of the developed steam generator was investigated by performing the dynamic analysis for the steam generator cassette, flow induced vibration analysis for the tube bundle, and the thermo-mechanical analysis for the module header and tube. As for the manufacturing of steam generator, the numerical and the experimental simulation have been carried to control the amount of spring back and to eliminate residual stress. SMART steam generator cassette was developed by a sequential research of the aforementioned activities

  8. Steam generators - problems and prognosis

    International Nuclear Information System (INIS)

    Tapping, R.L.

    1997-05-01

    Steam-generator problems, largely a consequence of corrosion and fouling, have resulted in increased inspection requirements and more regulatory attention to steam-generator integrity. In addition, utilities have had to develop steam-generator life-management strategies, including cleaning and replacement, to achieve design life. This paper summarizes the pertinent data to 1993/1994, and presents an overview of current steam-generator management practices. (author)

  9. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    International Nuclear Information System (INIS)

    Mendler, O.J.; Takeuchi, K.; Young, M.Y.

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results

  10. Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mendler, O J; Takeuchi, K; Young, M Y

    1986-10-01

    The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

  11. Steam generators: critical components in nuclear steam supply systems

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Guille, P D

    1974-02-28

    Steam generators are critical components in power reactors. Even small internal leaks result in costly shutdowns for repair. Surveys show that leaks have affected one half of all water-cooled reactors in the world with steam generators. CANDU reactors have demonstrated the highest reliability. However, AECL is actively evolving new technology in design, manufacture, inspection and operation to maintain reliability. (auth)

  12. Steam power plant

    International Nuclear Information System (INIS)

    Campbell, J.W.E.

    1981-01-01

    This invention relates to power plant forced flow boilers operating with water letdown. The letdown water is arranged to deliver heat to partly expanded steam passing through a steam reheater connected between two stages of the prime mover. (U.K.)

  13. Modelling of steam condensation in the primary flow channel of a gas-heated steam generator

    International Nuclear Information System (INIS)

    Kawamura, H.; Meister, G.

    1982-10-01

    A new simulation code has been developed for the analysis of steam ingress accidents in high temperatures reactors which evaluates the heat transfer in a steam generator headed by a mixture of helium and water steam. Special emphasis is laid on the analysis of steam condensation in the primary circuit of the steam generator. The code takes wall and bulk condensation into account. A new method is proposed to describe the entrainment of water droplets in the primary gas flow. Some typical results are given. Steam condensation in the primary channel may have a significant effect on temperature distributions. The effect on the heat transferred by the steam generator, however, is found to be not so prominent as might be expected. The reason is discussed. A simplified code will also be described, which gives results with reasonable accuracy within much shorter execution times. This code may be used as a program module in a program simulating the total primary circuit of a high temperature reactor. (orig.) [de

  14. Steam turbines for the future

    International Nuclear Information System (INIS)

    Trassl, W.

    1988-01-01

    Approximately 75% of the electrical energy produced in the world is generated in power plants with steam turbines (fossil and nuclear). Although gas turbines are increasingly applied in combined cycle power plants, not much will change in this matter in the future. As far as the steam parameters and the maximum unit output are concerned, a certain consolidation was noted during the past decades. The standard of development and mathematical penetration of the various steam turbine components is very high today and is applied in the entire field: For saturated steam turbines in nuclear power plants and for steam turbines without reheat, with reheat and with double reheat in fossil-fired power plants and for steam turbines with and without reheat in combined cycle power plants. (orig.) [de

  15. The Invisibility of Steam

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2014-01-01

    Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

  16. Progress in fuel processing for PEMFC systems for transport applications

    Energy Technology Data Exchange (ETDEWEB)

    Dams, A J; Hayter, P R; Moore, S C

    1998-07-01

    Wellman CJB Limited has been developing fuel processors for PEMFC systems for transport applications using a range of feedstocks. Feedstocks that can be processed to produce a hydrogen-rich gas stream suitable for use with a PEMFC include methanol, gasoline, diesel, LPG, dimethylether, marine diesel and aviation fuel. The basic fuel processor is a steam reformer combined with a selective carbon monoxide oxidation stage. Depending on the nature of the liquid feedstock, other process steps will be required such as vaporizer, desulfurizer, pre-reformer and high and low temperature shift reactors. Work on methanol reforming has been specifically targeted at a PEMFC driven passenger car as part of a multinational European Community JOULE programme called MERCATOX. The objective is to develop and test a compact and fast response methanol reformer and gas clean-up unit to meet a car manufacturer's specification. The method of construction is to coat a methanol reforming catalyst onto one side of a metal corrugated plate. On the other side is a coated combustion catalyst which burns fuel cell off-gas to provide the endothermic heat for the methanol reforming reaction. A number of these plates are assembled in a compact unit ensuring good heat transfer. The gas clean-up unit is similarly constructed with a selective oxidation catalyst on one side and a thermal fluid on the other. Initial tests have indicated a superior performance to conventional packed bed reformers in terms of response and start-up time. Steam reforming of gasoline, diesel, LPG, dimethylether, marine diesel and aviation fuel has been demonstrated on a bench scale (0.5kW). The process steps commence with vaporization (except for LPG), desulfurization (except for dimethylether), prereforming, reforming, low and high temperature shift and selective oxidation. A simple technology demonstrator has shown that a hydrogen-rich mixture (75% hydrogen, 25% carbon dioxide) with less than 2ppm carbon monoxide can be

  17. Deliberate ignition of hydrogen-air-steam mixtures in condensing steam environments

    International Nuclear Information System (INIS)

    Blanchat, T.K.; Stamps, D.W.

    1997-05-01

    Large scale experiments were performed to determine the effectiveness of thermal glow plug igniters to burn hydrogen in a condensing steam environment due to the presence of water sprays. The experiments were designed to determine if a detonation or accelerated flame could occur in a hydrogen-air-steam mixture which was initially nonflammable due to steam dilution but was rendered flammable by rapid steam condensation due to water sprays. Eleven Hydrogen Igniter Tests were conducted in the test vessel. The vessel was instrumented with pressure transducers, thermocouple rakes, gas grab sample bottles, hydrogen microsensors, and cameras. The vessel contained two prototypic engineered systems: (1) a deliberate hydrogen ignition system and (2) a water spray system. Experiments were conducted under conditions scaled to be nearly prototypic of those expected in Advanced Light Water Reactors (such as the Combustion Engineering (CE) System 80+), with prototypic spray drop diameter, spray mass flux, steam condensation rates, hydrogen injection flow rates, and using the actual proposed plant igniters. The lack of any significant pressure increase during the majority of the burn and condensation events signified that localized, benign hydrogen deflagration(s) occurred with no significant pressure load on the containment vessel. Igniter location did not appear to be a factor in the open geometry. Initially stratified tests with a stoichiometric mixture in the top showed that the water spray effectively mixes the initially stratified atmosphere prior to the deflagration event. All tests demonstrated that thermal glow plugs ignite hydrogen-air-steam mixtures under conditions with water sprays near the flammability limits previously determined for hydrogen-air-steam mixtures under quiescent conditions. This report describes these experiments, gives experimental results, and provides interpretation of the results. 12 refs., 127 figs., 16 tabs

  18. Connection of leak detectors for duplex tube plates of modular steam generator

    International Nuclear Information System (INIS)

    Banovec, J.; Konarik, M.; Vytopil, O.

    1985-01-01

    The sensors are connected to common line and column conductors. This connection significantly reduces the number of evaluation points and thus also the required number of evaluation unit channels. The reliability of the instrument is increased by each sensor being connected to two separate group conductors. Even upon failure of one of the conductors, the group of tube plates can be identified where a leak occurred. (J.B.)

  19. Anti-inflammatory and opioid-like activities in methanol extract of Mikania lindleyana, sucuriju

    Directory of Open Access Journals (Sweden)

    Frederico A. Vanderlinde

    2012-02-01

    Full Text Available Mikania lindleyana DC., Asteraceae (sucuriju, grows in the Amazon region, where is frequently used to treat pain, inflammatory diseases and scarring. This study was carried out to investigate phytochemical profile accompanied by in vivo antinociceptive and anti-inflammatory screening of n-hexane (HE, dichloromethane (DME and methanol (ME extracts obtained from the aerial parts of the plant. The oral administration of ME (0.1, 0.3, 1 g/kg caused a dose-related reduction (16.2, 42.1 e 70.2% of acetic acid-induced abdominal writhing while HE and DME (1 g/kg, p.o. were ineffective. In the hot plate test, ME (300 mg/kg, p.o. increased the latency of heat stimulus between 30 and 120 min and inhibited the first (45% and second (60% phases of nociception in the formalin test. The antinociception induced by ME or positive control fentanyl (150 µg/kg, s.c. in hot plate and formalin tests was prevented by naloxone (3 mg/kg, s.c.. When submitted to the carrageenan-induced peritonitis test, ME (0.5, 1.0, 2.0 g/kg, p.o. impaired leukocyte migration into the peritoneal cavity by 46.8, 59.4 and 64.8% respectively, while positive control dexamethasone (2 mg/kg, s.c., inhibited leukocyte migration by 71.1%. These results indicate that the antinociception obtained after oral administration of methanol extract of M. lindleyana involves anti-inflammatory mechanisms accompanied with opioid-like activity which could explain the use of the specie for pain and inflammatory diseases.

  20. Optimal design of marine steam turbine

    International Nuclear Information System (INIS)

    Liu Chengyang; Yan Changqi; Wang Jianjun

    2012-01-01

    The marine steam turbine is one of the key equipment in marine power plant, and it tends to using high power steam turbine, which makes the steam turbine to be heavier and larger, it causes difficulties to the design and arrangement of the steam turbine, and the marine maneuverability is seriously influenced. Therefore, it is necessary to apply optimization techniques to the design of the steam turbine in order to achieve the minimum weight or volume by means of finding the optimum combination of design parameters. The math model of the marine steam turbine design calculation was established. The sensitivities of condenser pressure, power ratio of HP turbine with LP turbine, and the ratio of diameter with height at the end stage of LP turbine, which influence the weight of the marine steam turbine, were analyzed. The optimal design of the marine steam turbine, aiming at the weight minimization while satisfying the structure and performance constraints, was carried out with the hybrid particle swarm optimization algorithm. The results show that, steam turbine weight is reduced by 3.13% with the optimization scheme. Finally, the optimization results were analyzed, and the steam turbine optimization design direction was indicated. (authors)

  1. Steam-water separator

    International Nuclear Information System (INIS)

    Modrak, T.M.; Curtis, R.W.

    1978-01-01

    A two-stage steam-water separating device is introduced, where the second stage is made as a cyclone separator. The water separated here is collected in the first stage of the inner tube and is returned to the steam raising unit. (TK) [de

  2. EPRI steam generator programs

    International Nuclear Information System (INIS)

    Martel, L.J.; Passell, T.O.; Bryant, P.E.C.; Rentler, R.M.

    1977-01-01

    The paper describes the current overall EPRI steam generator program plan and some of the ongoing projects. Because of the recent occurrence of a corrosion phenomenon called ''denting,'' which has affected a number of operating utilities, an expanded program plan is being developed which addresses the broad and urgent needs required to achieve improved steam generator reliability. The goal of improved steam generator reliability will require advances in various technologies and also a management philosophy that encourages conscientious efforts to apply the improved technologies to the design, procurement, and operation of plant systems and components that affect the full life reliability of steam generators

  3. Methanol May Function as a Cross-Kingdom Signal

    Science.gov (United States)

    Dorokhov, Yuri L.; Komarova, Tatiana V.; Petrunia, Igor V.; Kosorukov, Vyacheslav S.; Zinovkin, Roman A.; Shindyapina, Anastasia V.; Frolova, Olga Y.; Gleba, Yuri Y.

    2012-01-01

    Recently, we demonstrated that leaf wounding results in the synthesis of pectin methylesterase (PME), which causes the plant to release methanol into the air. Methanol emitted by a wounded plant increases the accumulation of methanol-inducible gene mRNA and enhances antibacterial resistance as well as cell-to-cell communication, which facilitates virus spreading in neighboring plants. We concluded that methanol is a signaling molecule involved in within-plant and plant-to-plant communication. Methanol is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of methanol into toxic formaldehyde. However, recent data showed that methanol is a natural compound in normal, healthy humans. These data call into question whether human methanol is a metabolic waste product or whether methanol has specific function in humans. Here, to reveal human methanol-responsive genes (MRGs), we used suppression subtractive hybridization cDNA libraries of HeLa cells lacking ADH and exposed to methanol. This design allowed us to exclude genes involved in formaldehyde and formic acid detoxification from our analysis. We identified MRGs and revealed a correlation between increases in methanol content in the plasma and changes in human leukocyte MRG mRNA levels after fresh salad consumption by volunteers. Subsequently, we showed that the methanol generated by the pectin/PME complex in the gastrointestinal tract of mice induces the up- and downregulation of brain MRG mRNA. We used an adapted Y-maze to measure the locomotor behavior of the mice while breathing wounded plant vapors in two-choice assays. We showed that mice prefer the odor of methanol to other plant volatiles and that methanol changed MRG mRNA accumulation in the mouse brain. We hypothesize that the methanol emitted by wounded plants may have a role in plant-animal signaling. The known positive effect of plant food intake on human health suggests a role for physiological methanol in

  4. Performance Evaluation of a Printed Circuit Steam Generator for Integral Reactors: A Feasibility Test

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hun Sik; Kang, Han-Ok; Yoon, Juhyeon; Kim, Young In; Kim, Keung Koo [KAERI, Daejeon (Korea, Republic of); Seo, Jang-won; Choi, Brain [Alfa Laval Korea Ltd., Daejeon (Korea, Republic of)

    2015-05-15

    SMART (System-integrated Modular Advanced ReacTor) is a small-sized integral type pressurized water reactor. It adopts advanced design features such as structural safety improvement, system simplification, and component modularization to achieve highly enhanced safety and improved economics. The design issues related to further safety enhancement and cost reduction have received significant attention to increase its competitiveness in the global small reactor market. For the cost reduction, it is important to design the reactor vessel as small as possible. Thus, it is necessary to reduce the volume of main components such as a steam generator. Its manufacturing processes of the chemical etching and diffusion bonding provide high effectiveness, high compactness, and inherent structural safety under high temperatures and high pressures. Thus, it is expected to be an alternative to the conventional shell and tube type steam generator in SMART. In this paper, simple thermal-hydraulic performance measurement of a small-scale printed circuit steam generator (PCSG) is conducted to investigate the feasibility of applying it to SMART. The simple thermal-hydraulic performance of the PCSG has been experimentally evaluated. A small-scale PCHE is employed to investigate the feasibility of operating it as a steam generator. The performance assessment reveals that the PCSG stably produces superheated steam, and the increased degree of superheat is obtained at lower water flow rate. However, the flow instability is increased with the decrease of the water flow rate. Thus, it is required to apply the orifice design into the cold side plate to suppress the density-wave oscillations. The pressure drops and heat transfer rates increase with the water flow rate.

  5. UPTF/TEST10B/RUN081, Steam/Water Flow Phenomena Reflood PWR Cold Leg Break LOCA

    International Nuclear Information System (INIS)

    1998-01-01

    1 - Description of test facility: The Upper Plenum Test Facility (UPTF) is a geometrical full-scale simulation of the primary system of the four-loop 1300 MWe Siemens/KWU pressurized water reactor (PWR) at Grafenrheinfeld. The test vessel, upper plenum and its internals, downcomer, primary loops, pressurizer and surge line are replicas of the reference plant. The core, coolant pumps, steam generators and containment of a PWR are replaced by simulators which simulate the boundary and initial conditions during end-of-blowdown, refill and reflood phase following a loss-of-coolant accident (LOCA) with a hot or cold leg break. The break size and location can be simulated in the broken loop. The emergency core coolant (ECC) injection systems at the UPTF are designed to simulate the various ECC injection modes, such as hot leg, upper plenum, cold leg, downcomer or combined hot and cold leg injection of different ECC systems of German and US/Japan PWRs. Moreover, eight vent valves are mounted in the core barrel above the hot leg nozzle elevation for simulation of ABB and B and W PWRs. The UPTF primary system is divided into the investigation and simulation areas. The investigation areas, which are the exact replicas of a GPWR, consist of the upper plenum with internals, hot legs, cold legs and downcomer. The realistic thermal-hydraulic behavior in the investigation areas is assured by appropriate initial and boundary conditions of the area interface. The boundary conditions are realized by above mentioned simulators, the setup and the operation of which are based on small-scale data and mathematical models. The simulation areas include core simulator, steam generator simulators, pump simulators and containment simulator. The steam production and entrainment in a real core during a LOCA are simulated by steam and water injection through the core simulator. 2 - Description of test: Investigation of steam/water flow phenomena at the upper tie plate and in the upper plenum and

  6. STEAM DALAM PEMBUATAN PAKAN UNTUK KOMODITAS AKUAKULTUR

    Directory of Open Access Journals (Sweden)

    Sukarman Sukarman

    2010-12-01

    Full Text Available Kualitas fisik pakan (pelet untuk hewan akuakultur sangat penting, karena akan dimasukkan ke dalam air dan diharapkan tidak banyak mencemari lingkungan. Salah satu faktor yang berpengaruh dalam menjaga kualitas fisik pakan adalah penambahan dan pengaturan steam pada saat proses pembuatan pelet. Steam adalah aliran gas yang dihasilkan oleh air pada saat mendidih. Steam dibagi menjadi 3 jenis yaitu steam basah, saturated steam, dan superheated steam. Steam yang digunakan dalam proses pembuatan pelet adalah saturated steam. Pengaruh penambahan steam pada kualitas pelet bisa mencapai 20%. Penambahan steam dengan jumlah dan kualitas yang tepat akan menghasilkan pelet berkualitas. Sedangkan jika pengaturan dan penambahannya tidak tepat, maka kualitas fisik pelet akan rendah dan kemungkinan bisa merusak kandungan nutrisi seperti vitamin dan protein. Penambahan steam yang benar bisa dilakukan di dalam kondisioner dengan mengatur retention time, sudut kemiringan paddle conditioner, kecepatan putaran bearing dan menjaga kualitas steam dari mesin boiler sampai dengan kondisioner.

  7. Determination of methanol in Iranian herbal distillates.

    Science.gov (United States)

    Shirani, Kobra; Hassani, Faezeh Vahdati; Azar-Khiavi, Kamal Razavi; Moghaddam, Zohreh Samie; Karimi, Gholamreza

    2016-06-01

    Herbal distillates have been used as beverages, for flavoring, or as phytomedicines in many countries for a long time. Recently, the occurrence of blindness after drinking herbal distillates has created concerns in Iran. The aim of this study was to determine the concentrations of methanol in herbal distillates produced in Iran. Eighty-four most commonly used herbal distillates purchased from herbal distillate factories were analyzed for methanol contents by gas chromatography and flame ionization detection, with ethanol as internal standard. In 15 herbal distillates, the methanol concentration was below the limit of quantitation. The methanol concentrations in all samples ranged from 43 to 277 mg/L. Forty-five samples contained methanol in excess of the Iranian standard. The maximum concentration was found in an herbal distillate of Mentha piperita (factory E) (277±12), and the minimum in a distillate of Carum carvi (factory B) (42.6 ± 0.5). Since the 45 Iranian herbal distillates containing methanol levels were beyond the legal limits according to the Iranian standard, it seems necessary to monitor the amount of methanol and give a warning to watch out for the latent risk problem of methanol uptake, and establish a definitive relationship between the degree of intoxication observed and the accumulation of methanol in the blood.

  8. Synthesis and optimization of steam system networks. 2. Multiple steam levels

    CSIR Research Space (South Africa)

    Price, T

    2010-08-01

    Full Text Available The use of steam in heat exchanger networks (HENs) can be reduced by the application of heat integration with the intention of debottlenecking the steam boiler and indirectly reducing the water requirement [Coetzee and Majozi. Ind. Eng. Chem. Res...

  9. Microbial and Chemical Shelf-Life of Vacuum Steam-Pasteurized Whole Flaxseed and Milled Flaxseed.

    Science.gov (United States)

    Shah, Manoj; Eklund, Bridget; Conde Lima, Luiz Gustavo; Bergholz, Teresa; Hall, Clifford

    2018-02-01

    Flaxseed is an oilseed with many health benefits. Flaxseed may be consumed raw or in processed form. In the raw form, there is a potential for microbial contamination. Several pasteurization methods have been used to reduce microbial contamination. However, such treatments may affect chemical properties of foods. In this study, vacuum steam-pasteurization was conducted on whole flaxseed and milled flaxseed using 4 different conditions (3 min at 75 °C, 3 min at 90 °C, 9 min at 90 °C, and 3 min at 105 °C). Microbial and chemical shelf-life was monitored for 28 wk (36 wk for aerobic plate counts). Significant reduction (P chemical indices measured. Only small changes were observed in the chemical indices after vacuum steam-pasteurization for both pasteurized whole flaxseed and milled flaxseed as compared to the unpasteurized flaxseed at most instances. Vacuum steam-pasteurization can be used as a safe alternative for the microbial reduction of low-moisture products, such as flaxseed, without significantly affecting chemical stability. Vacuum steam-pasteurization can be effectively used for the treatment of whole flaxseed and milled flaxseed to reduce spoilage microorganisms, such as total aerobes and yeasts and molds. In addition, this pasteurization method had minimal effects on several chemical shelf-life parameters with positive impact on SDG of the processed flaxseed. © 2018 Institute of Food Technologists®.

  10. A Review of Study on Thermal Energy Transport System by Synthesis and Decomposition Reactions of Methanol

    Science.gov (United States)

    Liu, Qiusheng; Yabe, Akira; Kajiyama, Shiro; Fukuda, Katsuya

    The study on thermal energy transport system by synthesis and decomposition reactions of methanol was reviewed. To promote energy conservation and global environment protection, a two-step liquid-phase methanol synthesis process, which starts with carbonylation of methanol to methyl formate, then followed by the hydrogenolysis of the formate, was studied to recover wasted or unused discharged heat from industrial sources for the thermal energy demands of residential and commercial areas by chemical reactions. The research and development of the system were focused on the following three points. (1) Development of low-temperature decomposition and synthetic catalysts, (2) Development of liquid phase reactor (heat exchanger accompanying chemical reaction), (3) Simulation of the energy transport efficiency of entire system which contains heat recovery and supply sections. As the result of the development of catalyst, promising catalysts which agree with the development purposes for the methyl formate decomposition reaction and the synthetic reaction are being developed though some studies remain for the methanol decomposition and synthetic reactions. In the fundamental development of liquid phase reactor, the solubilities of CO and H2 gases in methanol and methyl formate were measured by the method of total pressure decrease due to absorption under pressures up to 1500kPa and temperatures up to 140°C. The diffusivity of CO gas in methanol was determined by measuring the diameter and solution time of single CO bubbles in methanol. The chemical reaction rate of methanol synthesis by hydrogenolysis of methyl formate was measured using a plate-type of Raney copper catalyst in a reactor with rectangular channel and in an autoclave reactor. The reaction characteristics were investigated by carrying out the experiments at various temperatures, flow rates and at various catalyst development conditions. We focused on the effect of Raney copper catalyst thickness on the liquid

  11. Steam cleaning device

    International Nuclear Information System (INIS)

    Karaki, Mikio; Muraoka, Shoichi.

    1985-01-01

    Purpose: To clean complicated and long objects to be cleaned having a structure like that of nuclear reactor fuel assembly. Constitution: Steams are blown from the bottom of a fuel assembly and soon condensated initially at the bottom of a vertical water tank due to water filled therein. Then, since water in the tank is warmed nearly to the saturation temperature, purified water is supplied from a injection device below to the injection device above the water tank on every device. In this way, since purified water is sprayed successively from below to above and steams are condensated in each of the places, the entire fuel assembly elongated in the vertical direction can be cleaned completely. Water in the reservoir goes upward like the steam flow and is drained together with the eliminated contaminations through an overflow pipe. After the cleaning has been completed, a main steam valve is closed and the drain valve is opened to drain water. (Kawakami, Y.)

  12. Batch extractive distillation for high purity methanol

    International Nuclear Information System (INIS)

    Zhang Weijiang; Ma Sisi

    2006-01-01

    In this paper, the application in chemical industry and microelectronic industry, market status and the present situation of production of high purity methanol at home and abroad were introduced firstly. Purification of industrial methanol for high purity methanol is feasible in china. Batch extractive distillation is the best separation technique for purification of industrial methanol. Dimethyl sulfoxide was better as an extractant. (authors)

  13. Experimental Validation of Methanol Crossover in a Three-dimensional, Two-Fluid Model of a Direct Methanol Fuel Cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2012-01-01

    A fully coupled three-dimensional, steady-state, two-fluid, multi-component and non-isothermal DMFC model has been developed in the commercial CFD package CFX 13 (ANSYS inc.). It accounts for the presence of micro porous layers, non-equilibrium phase change, and methanol and water uptake...... in the ionomer phase of the catalytic layer, and detailed membrane transport of methanol and water. In order to verify the models ability to predict methanol crossover, simulation results are compared with experimental measurements under different current densities along with air and methanol stoichiometries....... Methanol crossover is indirectly measured based on the combined anode and cathode exhaust CO2 mole fraction and by accounting for the CO2 production at the anode as a function of current density. This approach is simple and assumes that all crossed over methanol is oxidized. Moreover, it takes CO2...

  14. Steam purity in PWRs

    International Nuclear Information System (INIS)

    Hopkinson, J.

    1982-01-01

    Impurities enter the secondary loop of the PWR through both makeup water from lake or well and cooling-water leaks in the condenser. These impurities can be carried to the steam generator, where they cause corrosion deposits to form. Corrosion products in steam are swept further through the system and become concentrated at the point in the low-pressure turbine where steam begins to condense. Several plants have effectively reduced impurities, and therefore corrosion, by installing a demineralizer for the makeup water, a resin-bed system to clean condensed steam from the condenser, and a deaerator to remove oxygen from the water and so lower the risk of system metal oxidation. 5 references, 1 figure

  15. Recycling of greenhouse gases via methanol

    Energy Technology Data Exchange (ETDEWEB)

    Bill, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Eliasson, B; Kogelschatz, U [ABB Corporate Research Center, Baden-Daettwil (Switzerland)

    1997-06-01

    Greenhouse gas emissions to the atmosphere can be mitigated by using direct control technologies (capture, disposal or chemical recycling). We report on carbon dioxide and methane recycling with other chemicals, especially with hydrogen and oxygen, to methanol. Methanol synthesis from CO{sub 2} is investigated on various catalysts at moderate pressures ({<=}30 bar) and temperatures ({<=}300{sup o}C). The catalysts show good methanol activities and selectivities. The conversion of CO{sub 2} and CH{sub 4} to methanol is also studied in a silent electrical discharge at pressures of 1 to 4 bar and temperatures close to room temperature. Methanol yields are given for mixtures of CO{sub 2}/H{sub 2}, CH{sub 4}/O{sub 2} and also for CH{sub 4} and air mixtures. (author) 2 figs., 5 refs.

  16. Wet-steam erosion of steam turbine disks and shafts

    International Nuclear Information System (INIS)

    Averkina, N. V.; Zheleznyak, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.; Shishkin, V. I.

    2011-01-01

    A study of wet-steam erosion of the disks and the rotor bosses or housings of turbines in thermal and nuclear power plants shows that the rate of wear does not depend on the diagrammed degree of moisture, but is determined by moisture condensing on the surfaces of the diaphragms and steam inlet components. Renovating the diaphragm seals as an assembly with condensate removal provides a manifold reduction in the erosion.

  17. Methanol utilizing Desulfotomaculum species utilizes hydrogen in a methanol-fed sulfate-reducing bioreactor.

    Science.gov (United States)

    Balk, Melike; Weijma, Jan; Goorissen, Heleen P; Ronteltap, Mariska; Hansen, Theo A; Stams, Alfons J M

    2007-01-01

    A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as sole energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration of 200 mg l(-1), while on H2/CO2, no apparent inhibition occurred up to a concentration of 500 mg l(-1). When strain WW1 was co-cultured under the same conditions with the methanol-utilizing, non-sulfate-reducing bacteria, Thermotoga lettingae and Moorella mulderi, both originating from the same bioreactor, growth and sulfide formation were observed up to 430 mg l(-1). These results indicated that in the co-cultures, a major part of the electron flow was directed from methanol via H2/CO2 to the reduction of sulfate to sulfide. Besides methanol, acetate, and hydrogen, strain WW1 was also able to use formate, malate, fumarate, propionate, succinate, butyrate, ethanol, propanol, butanol, isobutanol, with concomitant reduction of sulfate to sulfide. In the absence of sulfate, strain WW1 grew only on pyruvate and lactate. On the basis of 16S rRNA analysis, strain WW1 was most closely related to Desulfotomaculum thermocisternum and Desulfotomaculum australicum. However, physiological properties of strain WW1 differed in some aspects from those of the two related bacteria.

  18. Multifrequency eddy-current system for inspection of steam generator turbine

    International Nuclear Information System (INIS)

    Davis, T.J.

    1980-11-01

    The objectives of this program were to: determine the maximum advantage of the multifrequency eddy current method for nuclear steam generator tubing inspection; simplify system operating procedures and enhance presentation of mutifrequency data; and evaluate multifrequency methods for inspecting recently encountered types of anomalies such as circumferential cracks, inside diameter flaws, and flaws in dented regions. New test methods developed under the program have resulted in a dramatic improvement over earlier multifrequency work. The methods rely on judicious selection of test frequencies and the simultaneous use of differential and absolute multiparameter inspection. Flaws may be sized and profiled with increased accuracy over that of the single-frequency method, and improved rejection of indications from unwanted parameters such as support plates and probe wobble has been obtained. The ability to detect and size support cracks in both corroded and non-corroded supports has been demonstrated on a laboratory basis. A field-usable test system employing four test frequencies was developed under the program and has been evaluated in the EPRI steam generator mockup. Some of the new technology used in this system has been commercialized into the new Zetec MIZ-12 multifrequency system

  19. High-efficiency condenser of steam from a steam-gas mixture

    Science.gov (United States)

    Milman, O. O.; Krylov, V. S.; Ptakhin, A. V.; Kondratev, A. V.; Yankov, G. G.

    2017-12-01

    The design of a module for a high-efficiency condenser of steam with a high content (up to 15%) of noncondensable gases (NCGs) with a nearly constant steam-gas mixture (SGM) velocity during the condensation of steam has been developed. This module provides the possibility to estimate the operational efficiency of six condenser zones during the motion of steam from the inlet to the SGM suction point. Some results of the experimental tests of the pilot high-efficiency condenser module are presented. The dependence of the average heat transfer coefficient k¯ on the volumetric NCG concentration v¯ has been derived. It is shown that the high-efficiency condenser module can provide a moderate decrease in k¯ from 4400-4600 to 2600-2800 W/(m2 K) at v¯ ≈ 0.5-9.0%. The heat transfer coefficient distribution over different module zones at a heat duty close to its nominal value has been obtained. From this distribution, it can be seen that the average heat transfer coefficient decreases to 2600 W/(m2 K) at an NCG concentration v¯ = 7.5%, but the first condenser sections ( 1- 3) retain high values of k¯ at a level of no lower than 3200 W/(m2 K), and the last sections operate less well, having k¯ at a level of 1700 W/(m2 K). The dependence of the average heat transfer coefficient on the water velocity in condenser tubes has been obtained at a nearly nominal duty such that the extrapolation of this dependence to the water velocity of 2 m/s may be expected to give k¯ = 5000 W/(m2 K) for relatively pure steam, but an increase in k¯ at v¯ = 8% will be smaller. The effect of the gas removal device characteristic on the operation of the high-efficiency condenser module is described. The design developed for the steam condenser of a gas-turbine plant with a power of 25 MW, a steam flow rate of 40.2 t/h, and a CO2 concentration of up to 12% with consideration for the results of performed studies is presented.

  20. Steam injection for heavy oil recovery: Modeling of wellbore heat efficiency and analysis of steam injection performance

    International Nuclear Information System (INIS)

    Gu, Hao; Cheng, Linsong; Huang, Shijun; Li, Bokai; Shen, Fei; Fang, Wenchao; Hu, Changhao

    2015-01-01

    Highlights: • A comprehensive mathematical model was established to estimate wellbore heat efficiency of steam injection wells. • A simplified approach of predicting steam pressure in wellbores was proposed. • High wellhead injection rate and wellhead steam quality can improve wellbore heat efficiency. • High wellbore heat efficiency does not necessarily mean good performance of heavy oil recovery. • Using excellent insulation materials is a good way to save water and fuels. - Abstract: The aims of this work are to present a comprehensive mathematical model for estimating wellbore heat efficiency and to analyze performance of steam injection for heavy oil recovery. In this paper, we firstly introduce steam injection process briefly. Secondly, a simplified approach of predicting steam pressure in wellbores is presented and a complete expression for steam quality is derived. More importantly, both direct and indirect methods are adopted to determine the wellbore heat efficiency. Then, the mathematical model is solved using an iterative technique. After the model is validated with measured field data, we study the effects of wellhead injection rate and wellhead steam quality on steam injection performance reflected in wellbores. Next, taking cyclic steam stimulation as an example, we analyze steam injection performance reflected in reservoirs with numerical reservoir simulation method. Finally, the significant role of improving wellbore heat efficiency in saving water and fuels is discussed in detail. The results indicate that we can improve the wellbore heat efficiency by enhancing wellhead injection rate or steam quality. However, high wellbore heat efficiency does not necessarily mean satisfactory steam injection performance reflected in reservoirs or good performance of heavy oil recovery. Moreover, the paper shows that using excellent insulation materials is a good way to save water and fuels due to enhancement of wellbore heat efficiency

  1. Single-Step Syngas-to-Distillates (S2D) Synthesis via Methanol and Dimethyl Ether Intermediates: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A.; Lebarbier, Vanessa MC; Lizarazo Adarme, Jair A.; King, David L.; Zhu, Yunhua; Gray, Michel J.; Jones, Susanne B.; Biddy, Mary J.; Hallen, Richard T.; Wang, Yong; White, James F.; Holladay, Johnathan E.; Palo, Daniel R.

    2013-11-26

    The objective of the work was to enhance price-competitive, synthesis gas (syngas)-based production of transportation fuels that are directly compatible with the existing vehicle fleet (i.e., vehicles fueled by gasoline, diesel, jet fuel, etc.). To accomplish this, modifications to the traditional methanol-to-gasoline (MTG) process were investigated. In this study, we investigated direct conversion of syngas to distillates using methanol and dimethyl ether intermediates. For this application, a Pd/ZnO/Al2O3 (PdZnAl) catalyst previously developed for methanol steam reforming was evaluated. The PdZnAl catalyst was shown to be far superior to a conventional copper-based methanol catalyst when operated at relatively high temperatures (i.e., >300°C), which is necessary for MTG-type applications. Catalytic performance was evaluated through parametric studies. Process conditions such as temperature, pressure, gas-hour-space velocity, and syngas feed ratio (i.e., hydrogen:carbon monoxide) were investigated. PdZnAl catalyst formulation also was optimized to maximize conversion and selectivity to methanol and dimethyl ether while suppressing methane formation. Thus, a PdZn/Al2O3 catalyst optimized for methanol and dimethyl ether formation was developed through combined catalytic material and process parameter exploration. However, even after compositional optimization, a significant amount of undesirable carbon dioxide was produced (formed via the water-gas-shift reaction), and some degree of methane formation could not be completely avoided. Pd/ZnO/Al2O3 used in combination with ZSM-5 was investigated for direct syngas-to-distillates conversion. High conversion was achieved as thermodynamic constraints are alleviated when methanol and dimethyl are intermediates for hydrocarbon formation. When methanol and/or dimethyl ether are products formed separately, equilibrium restrictions occur. Thermodynamic relaxation also enables the use of lower operating pressures than what

  2. Hybrid preheat/recirculating steam generator

    International Nuclear Information System (INIS)

    Lilly, G.P.

    1985-01-01

    The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

  3. Methanol ice co-desorption as a mechanism to explain cold methanol in the gas-phase

    Science.gov (United States)

    Ligterink, N. F. W.; Walsh, C.; Bhuin, R. G.; Vissapragada, S.; van Scheltinga, J. Terwisscha; Linnartz, H.

    2018-05-01

    Context. Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The process that controls the transition from solid state to gas-phase methanol in cold environments is not understood. Aims: The goal of this work is to investigate whether thermal CO desorption provides an indirect pathway for methanol to co-desorb at low temperatures. Methods: Mixed CH3OH:CO/CH4 ices were heated under ultra-high vacuum conditions and ice contents are traced using RAIRS (reflection absorption IR spectroscopy), while desorbing species were detected mass spectrometrically. An updated gas-grain chemical network was used to test the impact of the results of these experiments. The physical model used is applicable for TW Hya, a protoplanetary disk in which cold gas-phase methanol has recently been detected. Results: Methanol release together with thermal CO desorption is found to be an ineffective process in the experiments, resulting in an upper limit of ≤ 7.3 × 10-7 CH3OH molecules per CO molecule over all ice mixtures considered. Chemical modelling based on the upper limits shows that co-desorption rates as low as 10-6 CH3OH molecules per CO molecule are high enough to release substantial amounts of methanol to the gas-phase at and around the location of the CO thermal desorption front in a protoplanetary disk. The impact of thermal co-desorption of CH3OH with CO as a grain-gas bridge mechanism is compared with that of UV induced photodesorption and chemisorption.

  4. A novel method of methanol concentration control through feedback of the amplitudes of output voltage fluctuations for direct methanol fuel cells

    International Nuclear Information System (INIS)

    An, Myung-Gi; Mehmood, Asad; Hwang, Jinyeon; Ha, Heung Yong

    2016-01-01

    This study proposes a novel method for controlling the methanol concentration without using methanol sensors for DMFC (direct methanol fuel cell) systems that have a recycling methanol-feed loop. This method utilizes the amplitudes of output voltage fluctuations of DMFC as a feedback parameter to control the methanol concentration. The relationship between the methanol concentrations and the amplitudes of output voltage fluctuations is correlated under various operating conditions and, based on the experimental correlations, an algorithm to control the methanol concentration with no sensor is established. Feasibility tests of the algorithm have been conducted under various operating conditions including varying ambient temperature with a 200 W-class DMFC system. It is demonstrated that the sensor-less controller is able to control the methanol-feed concentration precisely and to run the DMFC systems more energy-efficiently as compared with other control systems. - Highlights: • A new sensor-less algorithm is proposed to control the methanol concentration without using a sensor. • The algorithm utilizes the voltage fluctuations of DMFC as a feedback parameter to control the methanol feed concentration. • A 200 W DMFC system is operated to evaluate the validity of the sensor-less algorithm. • The algorithm successfully controls the methanol feed concentration within a small error bound.

  5. STEAM by Design

    Science.gov (United States)

    Keane, Linda; Keane, Mark

    2016-01-01

    We live in a designed world. STEAM by Design presents a transdisciplinary approach to learning that challenges young minds with the task of making a better world. Learning today, like life, is dynamic, connected and engaging. STEAM (Science, Technology, Environment, Engineering, Art, and Math) teaching and learning integrates information in…

  6. Equivalent properties for perforated plates. An analytical approach

    International Nuclear Information System (INIS)

    Cepkauskas, M.M.; Yang Jianfeng

    2005-01-01

    Structures that contain perforated plates have been a subject of interest in the Nuclear Industry. Steam generators, condensers and reactor internals utilize plates containing holes which act as flow holes or separate structures from flow by using a 'tube bank' design. The equivalent plate method has been beneficial in analyzing perforate plates. Details are found in various papers found in the bibliography. In addition the ASME code addresses perforated plates in Appendix A-8000, but is limited to a triangular hole pattern. This early work performed in this field utilized test data and analytical approaches. This paper is an examination of an analytical approach for determining equivalent plate mechanical and thermal properties. First a patch of the real plate is identified that provides a model for the necessary physical behavior of the plate. The average strain of this patch is obtained by first applying simplified one dimensional mechanical load to the patch, determining stress as a function of position, converting the stress to strain and then integrating the strain over the patch length. This average strain is then equated to the average strain of an equivalent fictitious rectangular patch. This results in obtaining equivalent Young's Modulus and Poison's Ratio for the equivalent plate in all three orthogonal directions. The corresponding equivalent shear modulus in all three directions is then determined. An orthotropic material stress strain matrix relationship is provided for the fictitious properties. By equating the real average strain with the fictitious average strain in matrix form, a stress multiplier is found to convert average fictitious stress to average real stress. This same type of process is repeated for heat conduction coefficients and coefficients of thermal expansion. Results are provided for both a square and triangular hole pattern. Reasonable results are obtained when comparing the effective Young's Modulus and Poison's Ratio with ASME

  7. Thermo-economic analysis of proton exchange membrane fuel cell fuelled with methanol and methane

    International Nuclear Information System (INIS)

    Suleiman, B.; Abdulkareem, A.S.; Musa, U.; Mohammed, I.A.; Olutoye, M.A.; Abdullahi, Y.I.

    2016-01-01

    Highlights: • Modified proton exchange membrane fuel cell was reported. • Thermolib software was used for the simulation of PEM fuel cell configurations. • Optimal operating parameters at 50 kW output of each process were determined. • Thermo-economic analysis is the most efficient way of process selection. • Methane system configuration has been identified as the best preferred PEM fuel cell. - Abstract: Exergy and economic analysis is often used to find and identify the most efficient process configuration for proton exchange membrane fuel cell from the thermo-economic point of view. This work gives an explicit account of the synergetic effect of exergetic and economic analysis of proton exchange membrane fuel cell (PEMFC) using methanol and methane as fuel sources. This was carried out through computer simulation using Thermolib simulation toolbox. Data generated from the simulated model were subsequently used for the thermodynamic and economic analysis. Analysis of energy requirement for the two selected processes revealed that the methane fuelled system requires the lower amount of energy (4.578 kJ/s) in comparison to the methanol fuelled configuration which requires 180.719 J/s. Energy analysis of both configurations showed that the principle of energy conservation was satisfied while the result of the exergy analysis showed high exergetic efficiency around major equipment (heat exchangers, compressors and pumps) of methane fuelled configuration. Higher irreversibility rate were observed around the burner, stack, and steam reformer. These trends of exergetic efficiency and irreversibility rate were observed around equipment in the methanol fuelled system but with lower performance when compared with the methane fuelled process configuration. On the basis of overall exergetic efficiency and lost work, the methanol system was more efficient with lower irreversibility rate of 547.27 kJ/s and exergetic efficiency of 34.44% in comparison with the methane

  8. Production of methanol/DME from biomass

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Münster-Swendsen, Janus

    In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier...... cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51...... gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic...

  9. Performance tests and efficiency analysis of Solar Invictus 53S - A parabolic dish solar collector for direct steam generation

    Science.gov (United States)

    Jamil, Umer; Ali, Wajahat

    2016-05-01

    This paper presents the results of performance tests conducted on Solar Invictus 53S `system'; an economically effective solar steam generation solution designed and developed by ZED Solar Ltd. The system consists of a dual axis tracking parabolic solar dish and bespoke cavity type receiver, which works as a Once Through Solar Steam Generator `OTSSG' mounted at the focal point of the dish. The overall performance and efficiency of the system depends primarily on the optical efficiency of the solar dish and thermal efficiency of the OTSSG. Optical testing performed include `on sun' tests using CCD camera images and `burn plate' testing to evaluate the sunspot for size and quality. The intercept factor was calculated using a colour look-back method to determine the percentage of solar rays focused into the receiver. Solar dish tracking stability tests were carried out at different times of day to account for varying dish elevation angles and positions, movement of the sunspot centroid was recorded and logged using a CCD camera. Finally the overall performance and net solar to steam efficiency of the system was calculated by experimentally measuring the output steam parameters at varying Direct Normal Insolation (DNI) levels at ZED Solar's test facility in Lahore, Pakistan. Thermal losses from OTSSG were calculated using the known optical efficiency and measured changes in output steam enthalpy.

  10. CANDU steam generator life management

    International Nuclear Information System (INIS)

    Tapping, R.L.; Nickerson, J.; Spekkens, P.; Maruska, C.

    1998-01-01

    Steam generators are a critical component of a nuclear power reactor, and can contribute significantly to station unavailability, as has been amply demonstrated in Pressurized Water Reactors (PWRs). CANDU steam generators are not immune to steam generator degradation, and the variety of CANDU steam generator designs and tube materials has led to some unexpected challenges. However, aggressive remedial actions, and careful proactive maintenance activities, have led to a decrease in steam generator-related station unavailability of Canadian CANDUs. AECL and the CANDU utilities have defined programs that will enable existing or new steam generators to operate effectively for 40 years. Research and development work covers corrosion and mechanical degradation of tube bundles and internals, chemistry, thermalhydraulics, fouling, inspection and cleaning, as well as provision for specially tool development for specific problem solving. A major driving force is development of CANDU-specific fitness-for-service guidelines, including appropriate inspection and monitoring technology to measure steam generator condition. Longer-range work focuses on development of intelligent on-line monitoring for the feedwater system and steam generator. New designs have reduced risk of corrosion and fouling, are more easily inspected and cleaned, and are less susceptible to mechanical damage. The Canadian CANDU utilities have developed programs for remedial actions to combat degradation of performance (Gentilly-2, Point Lepreau, Bruce A/B, Pickering A/B), and have developed strategic plans to ensure that good future operation is ensured. The research and development program, as well as operating experience, has identified where improvements in operating practices and/or designs can be made in order to ensure steam generator design life at an acceptable capacity factory. (author)

  11. NMR studies on graphite-methanol system

    International Nuclear Information System (INIS)

    El-Akkad, T.M.

    1977-01-01

    The nuclear magnetic relaxation times for protons of methanol on graphite have been studied. The perpendicular and the transversal magnetization as a function of temperature were measured. The results show that the presence of graphite slowed down the methanol movement compared with that in the pure alcohol, and that the methanol molecules are attached to the graphite surface via methyl groups. (author)

  12. Methanol utilizing Desulfotomaculum species utilizes hydrogen in a methanol-fed sulfate-reducing bioreactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Goorissen, H.P.; Ronteltap, M.; Hansen, T.A.; Stams, A.J.M.

    2007-01-01

    A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as sole energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration of 200 mg l(-1), while on H-2/CO2, no

  13. Waste-to-methanol: Process and economics assessment.

    Science.gov (United States)

    Iaquaniello, Gaetano; Centi, Gabriele; Salladini, Annarita; Palo, Emma; Perathoner, Siglinda; Spadaccini, Luca

    2017-11-01

    The waste-to-methanol (WtM) process and related economics are assessed to evidence that WtM is a valuable solution both from economic, strategic and environmental perspectives. Bio-methanol from Refuse-derived-fuels (RdF) has an estimated cost of production of about 110€/t for a new WtM 300t/d plant. With respect to waste-to-energy (WtE) approach, this solution allows various advantages. In considering the average market cost of methanol and the premium as biofuel, the WtM approach results in a ROI (Return of Investment) of about 29%, e.g. a payback time of about 4years. In a hybrid scheme of integration with an existing methanol plant from natural gas, the cost of production becomes a profit even without considering the cap for bio-methanol production. The WtM process allows to produce methanol with about 40% and 30-35% reduction in greenhouse gas emissions with respect to methanol production from fossil fuels and bio-resources, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Production of methanol/DME from biomass

    Energy Technology Data Exchange (ETDEWEB)

    Ahrenfeldt, J.; Birk Henriksen, U.; Muenster-Swendsen, J.; Fink, A.; Roengaard Clausen, L.; Munkholt Christensen, J.; Qin, K.; Lin, W.; Arendt Jensen, P.; Degn Jensen, A.

    2011-07-01

    In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier types have been investigated in this project: 1) The Two-Stage Gasifier (Viking Gasifier), designed to produce a very clean gas to be used in a gas engine, has been connected to a lab-scale methanol plant, to prove that the gas from the gasifier could be used for methanol production with a minimum of gas cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51-58% (LHV). By using waste heat from the plants for district heating, the total energy efficiencies could reach 87-88% (LHV). 2) A lab-scale electrically heated entrained flow gasifier has been used to gasify wood and straw. Entrained flow gasifiers are today the preferred gasifier type for commercial coal gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic fraction of the biomass that is not converted to gas appears as soot. Thermodynamic computer models of DME and methanol plants based on using entrained flow gasification were created to show the potential of such plants. These models showed that the potential torrefied biomass to DME/methanol + net electricity energy efficiency was 65-71% (LHV). Different routes to produce liquid transport fuels from biomass are possible. They include production of RME (rapeseed oil

  15. Mitigation of caustic stress corrosion cracking of steam generator tube materials by blowdown -a case study

    International Nuclear Information System (INIS)

    Dutta, Anu; Patwegar, I.A.; Chaki, S.K.; Venkat Raj, V.

    2000-01-01

    The vertical U-tube steam generators are among the most important equipment in nuclear power plants as they form the vital link between the reactor and the turbogenerator. Over ∼ 35 years of operating experience of water cooled reactor has demonstrated that steam generator tubes are susceptible to various forms of degradation. This degradation leads to failure and outages of the power plant. A majority of these failures have been attributed to concentrated alkali attacks in the low flow areas such as crevices in the tube to tube sheet joints, baffle plate location and the areas of sludge deposits. Free hydroxides can be produced by improper maintenance of phosphate chemical control in the secondary side of the steam generators and also by the thermal decomposition of impurities present in the condenser cooling water which may leak into the feed water through the condenser tubes. The free hydroxides concentrate in the low flow areas. This buildup of free hydroxide in combination with residual stress leads to caustic stress corrosion cracking. In order to mitigate caustic stress corrosion cracking of Inconel 600 tubes, the trend is to avoid phosphate dosing. Instead All Volatile Treatment (AVT) for secondary water is used backed by full flow condensate polishing. Sodium hydroxide concentration is now being considered as the basis for steam generator blowdown. A methodology has been established for determining the blowdown requirement in order to mitigate caustic stress corrosion cracking in the secondary side of the vertical U-tube natural circulation steam generator. A case study has been carried out for zero solid treatment (AVT coupled with full flow condensate polishing plant) water chemistry. Only continuous blowdown schemes have been studied based on maximum caustic concentration permissible in the secondary side of the steam generator. The methodology established can also be used for deciding concentration of any other impurities

  16. Identification of leaky steam generators by iodine mapping technique and development of tools for cutting of tubes of steam generators of Indian PHWRS

    International Nuclear Information System (INIS)

    Subba Rao, D.

    2006-01-01

    Kakrapar Atomic Power Station (2X220 MWe) located in Mandvi Taluka of Surat District in the state of Gujarat is the fifth Nuclear Power Station of the country. It has got an excellent record in the field of operation, safety, public awareness and emergency preparedness. KAPS Unit -1 achieved first criticality in Sep-1992 and was declared for commercial operation in may-1993. KAPS Unit -2 achieved first criticality in Jan-1995 and was declared for commercial operation in Sep-1995. So far station has generated about 30 billion units.Unit-1 achieved 98.4% and was graded as a world's No.1 in year 2002 amongst all CANDU type reactors. KAPS Unit -1 has made another record of operating continuously for more than 300 days in Indian PHWR s operating history. This paper mainly deals with the Indian PHWRs Steam Generators (SG) tube leaks, leaky steam generator identification by Iodine mapping, and development of special tool for cutting, removal and plugging of leaky tubes. These Steam Generators are designed by M/s Kraft Werke Union (KWU) of Siemens Group, West Germany, and Manufactured by M/s ENSA, SPAIN for Unit- 1 and by M/s MAN-GHH, Germany for Unit- 2. First time in October-2002 one of the Steam Generators of Unit-1 developed tube leak. To identify leaky Steam Generator, KAPS has established a method of Iodine mapping. With that the leaky SG was identified in very short time and corrective actions were taken immediately. Total three tube leaks (two in SG-4 of Unit-1 and one in SG-1 of unit-2) were experienced in both Units'. Following observations were made on SG tubes failure: All failures were in cold leg side; All Failures / deterioration locations were in front of main feed water nozzle; All Failures / deterioration locations were observed to be just above tube support plate (TSP) number 4 or 5; Deterioration ( i.e. wall thinning) observed from OD side and these tubes were adjacent to failed tubes; In all the three incidents, failed / deteriorated tubes were

  17. Facility to separate water and steam

    International Nuclear Information System (INIS)

    Loesel, G.

    1977-01-01

    The water/steam mixture from the pressure vessel e.g. of a BWR is separated by means of centrifugal separators untilizing the natural separation of steam. The steam is supplied to a steam drying vessel and the water to a water collecting tank. These vessels may be combined to a common vessel or connected through additional pipes. From the water collecting tank, arranged below the steam dryer, a feedwater pipe runs back to the pressure vessel. By construction out of individual components cleaning, decontamination, and operating control are essentially simplified. (RW) 891 RW [de

  18. Investigations into low pressure methanol synthesis

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek

    The central topic of this work has been synthesis, characterization and optimization of novel Ni-Ga based catalysts for hydrogenation of CO2 to methanol. The overall goal was to search for materials that could be used as a low temperature (and low pressure) methanol synthesis catalyst....... This is required for small scale delocalized methanol production sites, where installation of energy demanding compression units should be avoided. The work was triggered by DFT calculations, which showed that certain bimetallic systems are active towards methanol synthesis from CO2 and H2 at ambient pressure...... containing 5:3 molar ratio of Ni:Ga, the intrinsic activity (methanol production rate per active surface area) is comparable to that of highly optimised Cu/ZnO/Al2O3. Formation of the catalyst was investigated with the aid of in-situ XRD and in-situ XAS techniques. The mechanism of alloying was proposed...

  19. Drying system for steam generators, particularly for steam generators of nuclear power stations

    International Nuclear Information System (INIS)

    Lavalerie, Claude; Borrel, Christian.

    1982-01-01

    A drying system is described which allows for modular construction and which provides a significant available exchange area in a reduced volume. All the drying elements are identical and are distributed according to a ternay circular symmetry and are placed radially and associated to steam guiding facilities which alternately provide around the axis of revolution an output volume of dry steam from one element and an input volume of wet steam in the following element [fr

  20. The fate of methanol in anaerobic bioreactors

    NARCIS (Netherlands)

    Florencio, L.

    1994-01-01

    Methanol is an important component of certain industrial wastewaters. In anaerobic environments, methanol can be utilized by methanogens and acetogens. In wastewater treatment plants, the conversion of methanol into methane is preferred because this conversion is responsible for chemical

  1. Steam generator cleaning campaigns at Bruce A: 1993-1996

    International Nuclear Information System (INIS)

    Puzzuoli, F.V.; Leinonen, P.J.; Lowe, G.A.

    1997-01-01

    Boiler chemical cleaning (BOCC) and high-pressure water lancing operations were performed during the Bruce A 1993 Unit 3, 1994 Unit 3, 1995 Unit 1 and 1996 Unit 3 outages to remove secondary side deposits. High-pressure water lancing focused on three boiler areas: tube support plates, to remove broached hole deposits, hot leg U-bend supports to dislodge deposits contributing to boiler tube stress corrosion cracking and tube sheets with the aim of removing accumulated sludge piles and post BOCC insoluble residues. The chemical cleaning processes applied were modified versions of the one developed by the Electric Power Research Institute/Steam Generator Owners Group. During these BOCC operations, corrosion for several key boiler materials was monitored and was well below the specified allowances

  2. International examples of steam generator replacement

    International Nuclear Information System (INIS)

    Wiechmann, K.

    1993-01-01

    Since 1979-1980 a total of twelve nuclear power plants world-wide have had their steam generators replaced. The replacement of the Combustion steam generators in the Millstone-2 plant in the United States was completed very recently. Steam generator replacement activities are going on at present in four plants. In North Anna, the steam generators have been under replacement since January 1990. In Japan, preparations have been started for Genkai-1. Since January 1992, the two projects in Beznau-1, Switzerland, and Doel-3, Belgium, have bee planned and executed in parallel. Why steam generator replacement? There are a number of defect mechanisms which give rise to the need for early steam generator replacement. One of the main reasons is the use of Inconel-600 as material for the heating tubes. Steam generator heating tubes made of Inconel-600 have been known to exhibit their first defects due to stress corrosion cracking after less than one year of operation. (orig.) [de

  3. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  4. Methods of conditioning direct methanol fuel cells

    Science.gov (United States)

    Rice, Cynthia; Ren, Xiaoming; Gottesfeld, Shimshon

    2005-11-08

    Methods for conditioning the membrane electrode assembly of a direct methanol fuel cell ("DMFC") are disclosed. In a first method, an electrical current of polarity opposite to that used in a functioning direct methanol fuel cell is passed through the anode surface of the membrane electrode assembly. In a second method, methanol is supplied to an anode surface of the membrane electrode assembly, allowed to cross over the polymer electrolyte membrane of the membrane electrode assembly to a cathode surface of the membrane electrode assembly, and an electrical current of polarity opposite to that in a functioning direct methanol fuel cell is drawn through the membrane electrode assembly, wherein methanol is oxidized at the cathode surface of the membrane electrode assembly while the catalyst on the anode surface is reduced. Surface oxides on the direct methanol fuel cell anode catalyst of the membrane electrode assembly are thereby reduced.

  5. French steam generator design developments

    International Nuclear Information System (INIS)

    Ginier, R.; Campan, J.L.; Pontier, M.; Leridon, A.; Remond, A.; Castello, G.; Holcblat, A.; Paurobally, H.

    1986-01-01

    From the outset of the French nuclear power program, a significant R and D effort has been invested in improvement of the design and operation of Pressurized Water Reactors including a special committment to improving steam generators. The steam generator enhancement program has spawned a wide variety of specific R and D resources, e.g., low temperature hydraulic models for investigation of areas with single-phase flow, and freon-filled models for simulation of areas of steam generators experiencing two-phase flow (tube bundles and moisture separators). For the moisture separators, a large scale research program using freon-filled models and highly sophisticated instrumentation was used. Tests at reactor sites during startup of both 900 MWe and 1300 MWe have been used to validate the assumptions made on the basis of loop tests. These tests also demonstrated the validity of using freon to simulate two-phase flow conditions. The wealth of knowledge accumulated by the steam generator R and D program has been used to develop a new design of steam generators for the N4 plants. The current R and D effort is aimed at qualifying the N4 steam generator model and developing more comprehensive models. One prong of the R and D effort is the Megeve program. Megeve is a 25 MW steam generator which simulates operating conditions of the N4 model. The other prong is Clotaire, a freon-filled steam generator model which will be used to qualify thermal/hydraulic design codes used for multidimensional calculations for design of tube bundles

  6. Corrosion behavior of the tube - tubular plate joint zone in the presence of sediments

    International Nuclear Information System (INIS)

    Lucan, D.; Fulger, M.; Pirvan, I.; Cotolan, V.

    1997-01-01

    The corrosion is a very important problem which concerns the safe operation of steam generators. The predominant part of corrosion problems is related to the local concentration of aggressive species and/or to the impurities from the slow-flow regions, like those created by cracks in tube - tubular plate joint zones. The consequences of such local concentrations are very important and as such entail interest in the design and utilization of steam generators. This study presents the results of the corrosion tests performed under specific operation conditions of the secondary circuit in NPP (temperature, 260 o C; pressure, 5.1 MPa) on a crack simulating device made of carbon steel SA 508 cl.2 (forming the tubular plate) and Incoloy-800 (forming the tubes). The chemical medium of these tests was the following: solution of NaCl, 25g/l (pH=10.5); solution of NaCl, 50 g/l (pH=10.5); solution of NaCl, 75g/l (pH=10.5); solution of NaCl, 75g/l + solution of Na 2 SO 4 , 10 g/l (pH=10.5). The behavior of these two materials to corrosion was studied by metallographic investigations. The results are presented as microphotographs evidencing the occurrence of pitting corrosion first on material of the tubular plate, in the presence of medium particularly aggressive and on the material of the tubes. The aim of this study is to establish the corrosion mechanism as well as the formation of the oxide layer on the carbon steel in crack simulating devices. (authors)

  7. Electrophoretic deposits of boron on duralumin plates used for measuring neutron flux

    International Nuclear Information System (INIS)

    Lang, F.M.; Magnier, P.; Finck, C.

    1956-01-01

    Preparation of boron thin film deposits of around 1 mg per cm 2 on duralumin plates with a diameter of 8 cm. The boron coated plates for ionization chambers were originally prepared at the CEA by pulverization of boron carbides on sodium silicates. This method is not controlling precisely enough the quantity of boron deposit. Thus, an electrophoretic method is considered for a better control of the quantity of boron deposit in the scope of using in the future boron 10 which is costly and rare. The method described by O. Flint is not satisfying enough and a similar electrophoretic process has been developed. Full description of the method is given as well as explanation of the use of dried methanol as solvent, tannin as electrolyte and magnesium chloride to avoid alumina formation. (M.P.)

  8. Exergy Steam Drying and Energy Integration

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prem; Muenter, Claes (Exergy Engineering and Consulting, SE-417 55 Goeteborg (Sweden)). e-mail: verma@exergyse.com

    2008-10-15

    Exergy Steam Drying technology has existed for past 28 years and many new applications have been developed during this period. But during past few years the real benefits have been exploited in connection with bio-fuel production and energy integration. The steam dryer consists of a closed loop system, where the product is conveyed by superheated and pressurised carrier steam. The carrier steam is generated by the water vapours from the product being dried, and is indirectly superheated by another higher temperature energy source such as steam, flue gas, thermal oil etc. Besides the superior heat transfer advantages of using pressurised steam as a drying medium, the energy recovery is efficient and simple as the recovered energy (80-90%) is available in the form of steam. In some applications the product quality is significantly improved. Examples presented in this paper: Bio-Combine for pellets production: Through integration of the Exergy Steam Dryer for wood with a combined heat and power (CHP) plant, together with HP steam turbine, the excess carrier steam can be utilised for district heating and/or electrical power production in a condensing turbine. Bio-ethanol production: Both for first and second generation of ethanol can the Exergy process be integrated for treatment of raw material and by-products. Exergy Steam Dryer can dry the distillers dark grains and solubles (DDGS), wood, bagasse and lignin. Bio-diesel production: Oil containing seeds and fruits can be treated in order to improve both the quality of oil and animal feed protein, thus minimizing further oil processing costs and increasing the sales revenues. Sewage sludge as bio-mass: Municipal sewage sludge can be considered as a renewable bio-fuel. By drying and incineration, the combustion heat value of the sludge is sufficient for the drying process, generation of electrical energy and production of district heat. Keywords; Exergy, bio-fuel, bio-mass, pellets, bio-ethanol, biodiesel, bio

  9. Steam jet ejectors are examined automatically

    International Nuclear Information System (INIS)

    Lardiere, C.

    2013-01-01

    Steam jet ejectors are used in the nuclear industry particularly for the transfer of radioactive fluids. Their working is based on the Venturi effect and the conservation of energy. A steam ejector can be considered as a thermodynamical pump without mobile parts. The Descote enterprise manufactures a broad range of steam jet ejectors and the characterization and testing of the steam ejectors was made manually and empirically so far. A new test bench has been designed, the tests are led automatically and allow a more accurate characterization and optimization of the steam jet ejectors. (A.C.)

  10. Steam generator tube integrity program

    International Nuclear Information System (INIS)

    Dierks, D.R.; Shack, W.J.; Muscara, J.

    1996-01-01

    A new research program on steam generator tubing degradation is being sponsored by the U.S. Nuclear Regulatory Commission (NRC) at Argonne National Laboratory. This program is intended to support a performance-based steam generator tube integrity rule. Critical areas addressed by the program include evaluation of the processes used for the in-service inspection of steam generator tubes and recommendations for improving the reliability and accuracy of inspections; validation and improvement of correlations for evaluating integrity and leakage of degraded steam generator tubes, and validation and improvement of correlations and models for predicting degradation in steam generator tubes as aging occurs. The studies will focus on mill-annealed Alloy 600 tubing, however, tests will also be performed on replacement materials such as thermally-treated Alloy 600 or 690. An overview of the technical work planned for the program is given

  11. Growth of Candida boidinii on methanol and the activity of methanol-degrading enzymes as affected from formaldehyde and methylformate.

    Science.gov (United States)

    Aggelis, G; Margariti, N; Kralli, C; Flouri, F

    2000-06-23

    Formaldehyde and methylformate affect the growth of Candida boidinii on methanol and the activity of methanol-degrading enzymes. The presence of both intermediates in the feeding medium caused an increase in biomass yield and productivity and a decrease in the specific rate of methanol consumption. In the presence of formaldehyde, the activity of formaldehyde dehydrogenase and formate dehydrogenase was essentially increased, whereas the activity of methanol oxidase was decreased. On the contrary, the presence of methylformate caused an increase of the activity of methanol oxidase and a decrease of the activity of formaldehyde dehydrogenase and formate dehydrogenase. Interpretations concerning the yeast behavior in the presence of intermediate oxidation products were considered and discussed.

  12. Steam turbines for nuclear power plants

    International Nuclear Information System (INIS)

    Kosyak, Yu.F.

    1978-01-01

    Considered are the peculiarities of the design and operation of steam turbines, condensers and supplementary equipment of steam turbines for nuclear power plants; described are the processes of steam flow in humid-steam turbines, calculation and selection principles of main parameters of heat lines. Designs of the turbines installed at the Charkov turbine plant are described in detail as well as of those developed by leading foreign turbobuilding firms

  13. The Thermal Hydraulics of Tube Support Fouling in Nuclear Steam Generators

    International Nuclear Information System (INIS)

    Rummens, Helena E.C.; Rogers, J.T.; Turner, C.W.

    2004-01-01

    It is hypothesized that the thermal-hydraulic environment plays a role in the fouling of tube supports in nuclear steam generators. Experiments were performed to simulate the thermal-hydraulic environment near various designs of supports. Pressure loss, local velocity, turbulence intensity, and local void fraction were measured to characterize the effect of the support. Fouling mechanisms specific to supports were inferred from these experimental data and from actual steam generator inspection results. An analytical model was developed to predict the rate of particulate deposition on the supports, to better understand the complex processes involved.This paper presents the following set of tools for assessing the fouling propensity of a given support design: (1) proposed fouling mechanisms, (2) criteria for support fouling propensity, (3) correlation of fouling with parameters such as mass flux and quality, (4) descriptions of experimental tools such as flow visualization and measurement of pressure-loss profiles, and (5) analytical tools.An important conclusion from this and our previous work is that the fouling propensity is greater with broached support plates, both trefoil and quatrefoil, than with lattice bar supports and formed bar supports, in which significant cross flows occur

  14. Safety Picks up "STEAM"

    Science.gov (United States)

    Roy, Ken

    2016-01-01

    This column shares safety information for the classroom. STEAM subjects--science, technology, engineering, art, and mathematics--are essential for fostering students' 21st-century skills. STEAM promotes critical-thinking skills, including analysis, assessment, categorization, classification, interpretation, justification, and prediction, and are…

  15. Steam generator tube extraction

    International Nuclear Information System (INIS)

    Delorme, H.

    1985-05-01

    To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

  16. The relative impact of sizing errors on steam generator tube failure probability

    International Nuclear Information System (INIS)

    Cizelj, L.; Dvorsek, T.

    1998-01-01

    The Outside Diameter Stress Corrosion Cracking (ODSCC) at tube support plates is currently the major degradation mechanism affecting the steam generator tubes made of Inconel 600. This caused development and licensing of degradation specific maintenance approaches, which addressed two main failure modes of the degraded piping: tube rupture; and excessive leakage through degraded tubes. A methodology aiming at assessing the efficiency of a given set of possible maintenance approaches has already been proposed by the authors. It pointed out better performance of the degradation specific over generic approaches in (1) lower probability of single and multiple steam generator tube rupture (SGTR), (2) lower estimated accidental leak rates and (3) less tubes plugged. A sensitivity analysis was also performed pointing out the relative contributions of uncertain input parameters to the tube rupture probabilities. The dominant contribution was assigned to the uncertainties inherent to the regression models used to correlate the defect size and tube burst pressure. The uncertainties, which can be estimated from the in-service inspections, are further analysed in this paper. The defect growth was found to have significant and to some extent unrealistic impact on the probability of single tube rupture. Since the defect growth estimates were based on the past inspection records they strongly depend on the sizing errors. Therefore, an attempt was made to filter out the sizing errors and to arrive at more realistic estimates of the defect growth. The impact of different assumptions regarding sizing errors on the tube rupture probability was studied using a realistic numerical example. The data used is obtained from a series of inspection results from Krsko NPP with 2 Westinghouse D-4 steam generators. The results obtained are considered useful in safety assessment and maintenance of affected steam generators. (author)

  17. Steam jet mill-a prospective solution to industrial exhaust steam and solid waste.

    Science.gov (United States)

    Zhang, Mingxing; Chen, Haiyan

    2018-04-20

    Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300 °C and an inlet pressure of 0.2-0.6 MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d 50  = 4.785 μm, and another particle size is d 50  = 8.999 μm. For particle size d 50  = 8.999 μm, the inlet temperature is 296 °C and an inlet pressure is 0.54 MPa for the grinding chamber. The steam flow is 21.7 t/h. The yield of superfine powder is 73 t/h. The power consumption is 3.76 kW h/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.

  18. 49 CFR 229.105 - Steam generator number.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...

  19. Metabolic Engineering of Corynebacterium glutamicum for Methanol Metabolism

    Science.gov (United States)

    Witthoff, Sabrina; Schmitz, Katja; Niedenführ, Sebastian; Nöh, Katharina; Noack, Stephan

    2015-01-01

    Methanol is already an important carbon feedstock in the chemical industry, but it has found only limited application in biotechnological production processes. This can be mostly attributed to the inability of most microbial platform organisms to utilize methanol as a carbon and energy source. With the aim to turn methanol into a suitable feedstock for microbial production processes, we engineered the industrially important but nonmethylotrophic bacterium Corynebacterium glutamicum toward the utilization of methanol as an auxiliary carbon source in a sugar-based medium. Initial oxidation of methanol to formaldehyde was achieved by heterologous expression of a methanol dehydrogenase from Bacillus methanolicus, whereas assimilation of formaldehyde was realized by implementing the two key enzymes of the ribulose monophosphate pathway of Bacillus subtilis: 3-hexulose-6-phosphate synthase and 6-phospho-3-hexuloisomerase. The recombinant C. glutamicum strain showed an average methanol consumption rate of 1.7 ± 0.3 mM/h (mean ± standard deviation) in a glucose-methanol medium, and the culture grew to a higher cell density than in medium without methanol. In addition, [13C]methanol-labeling experiments revealed labeling fractions of 3 to 10% in the m + 1 mass isotopomers of various intracellular metabolites. In the background of a C. glutamicum Δald ΔadhE mutant being strongly impaired in its ability to oxidize formaldehyde to CO2, the m + 1 labeling of these intermediates was increased (8 to 25%), pointing toward higher formaldehyde assimilation capabilities of this strain. The engineered C. glutamicum strains represent a promising starting point for the development of sugar-based biotechnological production processes using methanol as an auxiliary substrate. PMID:25595770

  20. Methanol synthesis beyond chemical equilibrium

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Winkelman, J. G. M.; Wilbers, E.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2013-01-01

    In commercial methanol production from syngas, the conversion is thermodynamically limited to 0.3-0.7 leading to large recycles of non-converted syngas. This problem can be overcome to a significant extent by in situ condensation of methanol during its synthesis which is possible nowadays due to the

  1. Gentilly 2 steam generators Spring 2000 outage: tubesheet waterlance cleaning and inspection; upper bundle inspection

    International Nuclear Information System (INIS)

    Akeroyd, J.K.; Plante, S.

    2000-01-01

    A review of the secondary side maintenance activities recently completed during the Gentilly 2 Annual Spring 2000 Maintenance Outage. Activities included: 1) Tubesheet intertube waterlance cleaning and visual inspection, 2) First tube support plate, in-bundle visual inspection of the hot leg, and 3) Upper bundle tube support plate visual inspection. A description of the waterlancing and inspection equipment and setup in the RB at Gentilly 2 is provided. Several innovative techniques were successfully employed and yielded savings in critical path duration, labour and personnel radiation dose. These included accessing the SG tubesheet region through one handhole only and sludge removal utilizing the SG blowdown system. Plant personnel judged tubesheet sludge removal successful. Before and after results of the cleaning process along with samples of the visual inspection results are provided. Inspection of the first support plate, which was a repeat of an inspection done in 1997, was conducted along with an in-bundle inspection of the upper tube supports. Results are presented along with a discussion of the implications for future steam generator maintenance. (author)

  2. Methanol decomposition and oxidation on Ir(111)

    NARCIS (Netherlands)

    Weststrate, C.J.; Ludwig, W.; Bakker, J.W.; Gluhoi, A.C.; Nieuwenhuys, B.E.

    2007-01-01

    The adsorption, decompn., and oxidn. of methanol (CH3OH) has been studied on Ir(111) using temp.-programmed desorption and high-energy resoln. fast XPS. Mol. methanol desorption from a methanol-satd. surface at low temp. shows three desorption peaks, around 150 K (alpha ), around 170 K (beta 1), and

  3. Methanol in the L1551 Circumbinary Torus

    OpenAIRE

    White, Glenn J.; Fridlund, C. W. M.; Bergman, P.; Beardsmore, A.; Liseau, Rene; Phillips, R. R.

    2006-01-01

    We report observations of gaseous methanol in an edge-on torus surrounding the young stellar object L1551 IRS5. The peaks in the torus are separated by ~ 10,000 AU from L1551 IRS5, and contain ~ 0.03 earth masses of cold methanol. We infer that the methanol abundance increases in the outer part of the torus, probably as a result of methanol evaporation from dust grain surfaces heated by the shock luminosity associated with the shocks associated with the jets of an externally located x-ray sou...

  4. Groundwater issues relating to an Alaskan methanol spill

    International Nuclear Information System (INIS)

    Robertson, S.B.

    1992-01-01

    This paper reports on a Dec. 1989 methanol spill which resulted from sabotage to three railroad tank cars. Samples taken from nearby drinking-water wells and groundwater-monitoring wells were below the analytical detection limit. Monitoring well data demonstrated that groundwater flow was not toward local residential wells. Dilution by snow and subsequent freezing in the soil limited the downward spread of the methanol, an advantage not found in milder, more temperate conditions. Contaminated material was removed and processed to reclaim the methanol. Volatilization and biodegradation should remove any remaining methanol. Cleanup options were limited by the possible hazardous waste classification of the contaminated soil. The regulatory status of spilled methanol waste should be re-evaluated, especially if use of methanol as a motor fuel increases

  5. Susceptibility of CANDU steam generator preheater to cavitation erosion

    International Nuclear Information System (INIS)

    Laroche, S.L.; Sun, L.; Pietralik, J.M.

    2012-01-01

    In 2009, Darlington Steam Generator (SG) tube inspections revealed some tubes had degraded in the preheater. The tube degradation occurred at the clearance gap between the tube and the preheater baffle and reached up to 50% through-wall depth at the baffles in the middle portion of the preheater. The general pattern of the damage and the elemental composition analysis suggested that the degradation was the result of a hydrodynamic process, such as cavitation erosion. Cavitation erosion occurs when vapour bubbles exist or form in the flowing liquid and then these bubbles collapse violently in the vicinity of the wall. These bubbles collapse when steam bubbles contact water that is sufficiently subcooled, below the saturation temperature. In the gap between the tube and the preheater baffle, low flow will exist due to the pressure difference across the baffle plate. In addition, heat transfer occurs from the primary-side fluid to the secondary-side fluid within this clearance gap that is driven by the primary-to-secondary temperature difference. Factors, such as the tube position in the baffle hole and fouling, influence the local conditions and can cause subcooled boiling that result in cavitation. This paper presents a study of flow and heat transfer phenomena to determine the factors contributing to cavitation erosion in SG preheaters. The analysis used the THIRST1 code for a 3-dimensional thermalhydraulic simulation of the steam generators and the ANSYS FLUENT®2 code for detailed calculations of flow and heat transfer in the clearance gaps. This study identifies that tubes in the preheater region are susceptible to cavitation erosion and indicates that this area should be part of the station inspection program because, regardless of preheater design, some tubes may experience the thermalhydraulic conditions and undergo degradations similar to those observed for the tubes in Darlington SGs. (author)

  6. Signal analysis of steam line acoustics

    International Nuclear Information System (INIS)

    Martin, C. Samuel

    2003-01-01

    The vibration of nuclear steam piping is usually associated with pressure fluctuations emanating from flow disturbances such as steam generator nozzles, bends, or other pipe fittings. Flow separation at pipe tees and within steam chest manifolds or headers generate pressure fluctuations that propagate both upstream to steam generators as well as downstream to the steam turbine. Steady-state acoustic oscillations at various frequencies occur within the piping, possibly exciting structural vibrations. This paper focuses on the assessment of the origin of the disturbances using signal analyses of two dynamic pressure recordings from pressure transducers located along straight runs in the steam piping. The technique involves performing the cross spectrum to two dynamic pressure signals in piping between (1) the steam generator and steam chest header, and (2) between the header and steam turbine outlet. If, at a specified frequency, no causality occurs between the two signals then the cross spectra magnitude will be negligible. Of interest here is the value of the phase between the two signals for frequencies for which the magnitude of the cross spectrum is not negligible. It is shown in the paper that the direction of the dominant waves at all frequencies can be related to the phase angle from the cross spectrum. It has to be realized that pressure waves emanating from one source such as a steam generator will propagate along uniform steam pipes with little transformation or attenuation, but will be reflected at fittings and at inlets and outlets. Hence, the eventual steady-state time record at a given location in the piping is a result of not only the disturbance, but also reflections of earlier pulsations. Cross-spectral analyses has been employed to determine the direction of the dominant acoustic waves in the piping for various frequencies for which there are signals. To prove the technique, synthetic spectra are generated comprised of harmonic waves moving both

  7. Steam-water separator

    International Nuclear Information System (INIS)

    Modrak, T.M.; Curtis, R.W.

    1978-01-01

    The steam-water separator connected downstream of a steam generator consists of a vertical centrifugal separator with swirl blades between two concentric pipes and a cyclone separator located above. The water separated in the cyclone separator is collected in the inner tube of the centrifugal separator which is closed at the bottom. This design allows the overall height of the separator to be reduced. (DG) [de

  8. Sorption of methanol in alkali exchange zeolites

    NARCIS (Netherlands)

    Rep, M.; Rep, M.; Corma, Avelino; Palomares, A.E.; Palomares gimeno, A.E.; van Ommen, J.G.; Lefferts, Leonardus; Lercher, J.A.

    2000-01-01

    Metal cation methanol sorption complexes in MFI (ZSM5), MOR and X have been studied by in situ i.r. spectroscopy in order to understand the nature of interactions of methanol in the molecular sieve pores. The results show that (a) a freely vibrating hydroxy and methyl group of methanol exist on

  9. Erosion corrosion in wet steam

    International Nuclear Information System (INIS)

    Tavast, J.

    1988-03-01

    The effect of different remedies against erosion corrosion in wet steam has been studied in Barsebaeck 1. Accessible steam systems were inspected in 1984, 1985 and 1986. The effect of hydrogen peroxide injection of the transport of corrosion products in the condensate and feed water systems has also been followed through chemical analyses. The most important results of the project are: - Low alloy chromium steels with a chromium content of 1-2% have shown excellent resistance to erosion corrosion in wet steam. - A thermally sprayed coating has shown good resistance to erosion corrosion in wet steam. In a few areas with restricted accessibility minor attacks have been found. A thermally sprayed aluminium oxide coating has given poor results. - Large areas in the moisture separator/reheater and in steam extraction no. 3 have been passivated by injection of 20 ppb hydrogen peroxide to the high pressure steam. In other inspected systems no significant effect was found. Measurements of the wall thickness in steam extraction no. 3 showed a reduced rate of attack. - The injection of 20 ppb hydrogen peroxide has not resulted in any significant reduction of the iron level result is contrary to that of earlier tests. An increase to 40 ppb resulted in a slight decrease of the iron level. - None of the feared disadvantages with hydrogen peroxide injection has been observed. The chromium and cobalt levels did not increase during the injection. Neither did the lifetime of the precoat condensate filters decrease. (author)

  10. Advanced Catalysis Technologies: Lanthanum Cerium Manganese Hexaaluminate Combustion Catalysts for Flat Plate Reactor for Compact Steam Reformers

    Science.gov (United States)

    2008-12-01

    packed-bed steam reformer reactor using an open-flame or radiant burner as the heat source, the rate of heat transfer is limited by wall film and bed...resistances. Heat transfer can be effectively improved by replacing the burner /packed-bed system with parallel channels containing metal foam...combustion reactor was tested using the hexaaluminate catalyst in pellets and supported on FeCrAlloy metal foam. Both tests burned propane and JP-8

  11. Atmospheric deposition of methanol over the Atlantic Ocean

    Science.gov (United States)

    Yang, Mingxi; Nightingale, Philip D.; Beale, Rachael; Liss, Peter S.; Blomquist, Byron; Fairall, Christopher

    2013-01-01

    In the troposphere, methanol (CH3OH) is present ubiquitously and second in abundance among organic gases after methane. In the surface ocean, methanol represents a supply of energy and carbon for marine microbes. Here we report direct measurements of air–sea methanol transfer along a ∼10,000-km north–south transect of the Atlantic. The flux of methanol was consistently from the atmosphere to the ocean. Constrained by the aerodynamic limit and measured rate of air–sea sensible heat exchange, methanol transfer resembles a one-way depositional process, which suggests dissolved methanol concentrations near the water surface that are lower than what were measured at ∼5 m depth, for reasons currently unknown. We estimate the global oceanic uptake of methanol and examine the lifetimes of this compound in the lower atmosphere and upper ocean with respect to gas exchange. We also constrain the molecular diffusional resistance above the ocean surface—an important term for improving air–sea gas exchange models. PMID:24277830

  12. Fiber Fabry-Perot Force Sensor with Small Volume and High Performance for Assessing Fretting Damage of Steam Generator Tubes.

    Science.gov (United States)

    Huang, Peijian; Wang, Ning; Li, Junying; Zhu, Yong; Zhang, Jie

    2017-12-13

    Measuring the radial collision force between the steam generator tube (SGT) and the tube support plate (TSP) is essential to assess the fretting damage of the SGT. In order to measure the radial collision force, a novel miniaturized force sensor based on fiber Fabry-Perot (F-P) was designed, and the principle and characteristics of the sensor were analyzed in detail. Then, the F-P force sensor was successfully fabricated and calibrated, and the overall dimensions of the encapsulated fiber F-P sensor were 17 mm × 5 mm × 3 mm (L × W × H). The sensor works well in humid, high pressure (10 MPa), high temperature (350 °C), and vibration (40 kHz) environments. Finally, the F-P force sensors were installed in a 1:1 steam generator test loop, and the radial collision force signals between the SGT and the TSP were obtained. The experiments indicated that the F-P sensor with small volume and high performance could help in assessing the fretting damage of the steam generator tubes.

  13. On the effect of operating conditions in liquid-feed direct methanol fuel cells: A multiphysics modeling approach

    International Nuclear Information System (INIS)

    García-Salaberri, Pablo A.; Vera, Marcos

    2016-01-01

    A multiphysics model for liquid-feed Direct Methanol Fuel Cells is presented. The model accounts for two-dimensional (2D) across-the-channel anisotropic mass and charge transport in the anode and cathode Gas Diffusion Layers (GDLs), including the effect of GDL assembly compression and electrical contact resistances at the Bipolar Plate (BPP) and membrane interfaces. A one-dimensional (1D) across-the-membrane model is used to describe local species diffusion through the microporous layers, methanol/water crossover, proton transport, and electrochemical reactions, thereby coupling both GDL sub-models. The 2D/1D model is extended to the third dimension and supplemented with 1D descriptions of the flow channels to yield a 3D/1D + 1D model that is successfully validated. A parametric study is then conducted on the 2D/1D model to examine the effect of operating conditions on cell performance. The results show that an optimum methanol concentration exists that maximizes power output due to the trade-off between anode polarization and cathode mixed overpotential. For fixed methanol concentration, cell performance is largely affected by the oxygen supply rate, cell temperature, and liquid/gas saturation levels. There is also an optimal GDL compression due to the trade-off between ohmic and concentration losses, which strongly depends on BPP material and, more weakly, on the actual operating conditions. - Highlights: • A multiphysics model for liquid-feed DMFCs is presented. • GDL anisotropic transport, assembly compression, and ohmic contact resistances are considered. • The model is successfully validated against previous experimental data. • Optimum methanol concentrations, GDL compressions, and operating temperatures are reported. • Oxygen-starved conditions with spontaneous hydrogen evolution in the anode are also considered.

  14. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's Steam Generator Owners Group (SGOG II) will disband in December 1986 and be replaced in January 1987 by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue the emphasis on reliability and life extension that was carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems, such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation (NDE). These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and solve small problems before they become large problems

  15. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's (EPRI's) Steam Generator Owners Group (SGOG II) will disband in December 1986, and be replaced in January 1987, by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue to emphasize reliability and life extension, which were carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation. These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and to solve small problems before they become large problems

  16. Optical Fiber Demodulation System with High Performance for Assessing Fretting Damage of Steam Generator Tubes.

    Science.gov (United States)

    Huang, Peijian; Wang, Ning; Li, Junying; Zhu, Yong; Zhang, Jie; Xi, Zhide

    2018-01-12

    In order to access the fretting damage of the steam generator tube (SGT), a fast fiber Fabry-Perot (F-P) non-scanning correlation demodulation system based on a super luminescent light emitting diode (SLED) was performed. By demodulating the light signal coming out from the F-P force sensor, the radial collision force between the SGT and the tube support plate (TSP) was interrogated. For higher demodulation accuracy, the effects of the center wavelength, bandwidth, and spectrum noise of SLED were discussed in detail. Specially, a piezoelectric ceramic transducer (PZT) modulation method was developed to get rid of the interference of mode coupling induced by different types of fiber optics in the demodulation system. The reflectivity of optical wedge and F-P sensor was optimized. Finally, the demodulation system worked well in a 1:1 steam generator test loop and successfully demodulated a force signal of 32 N with a collision time of 2 ms.

  17. Optical Fiber Demodulation System with High Performance for Assessing Fretting Damage of Steam Generator Tubes

    Directory of Open Access Journals (Sweden)

    Peijian Huang

    2018-01-01

    Full Text Available In order to access the fretting damage of the steam generator tube (SGT, a fast fiber Fabry-Perot (F-P non-scanning correlation demodulation system based on a super luminescent light emitting diode (SLED was performed. By demodulating the light signal coming out from the F-P force sensor, the radial collision force between the SGT and the tube support plate (TSP was interrogated. For higher demodulation accuracy, the effects of the center wavelength, bandwidth, and spectrum noise of SLED were discussed in detail. Specially, a piezoelectric ceramic transducer (PZT modulation method was developed to get rid of the interference of mode coupling induced by different types of fiber optics in the demodulation system. The reflectivity of optical wedge and F-P sensor was optimized. Finally, the demodulation system worked well in a 1:1 steam generator test loop and successfully demodulated a force signal of 32 N with a collision time of 2 ms.

  18. A drier unit for steam separators

    International Nuclear Information System (INIS)

    Peyrelongue, J.-P.

    1973-01-01

    Description is given of a drier unit adapted to equip a water separator mounted in a unit for treating a wet steam fed from a high pressure enclosure, so as to dry and contingently superheat said steam prior to injecting same into a turbine low pressure stage. This drier unit is constituted by at least a stack of separating sheets maintained in parallel relationship and at a slight angle with respect to the horizontal so as to allow the water provided by wet steam to flow toward a channel communicating with a manifold, and by means for guiding the steam between the sheets and evenly distributing it. This can be applied to steam turbines in nuclear power stations [fr

  19. Steam explosion studies review

    International Nuclear Information System (INIS)

    Hwang, Moon Kyu; Kim, Hee Dong

    1999-03-01

    When a cold liquid is brought into contact with a molten material with a temperature significantly higher than the liquid boiling point, an explosive interaction due to sudden fragmentation of the melt and rapid evaporation of the liquid may take place. This phenomenon is referred to as a steam explosion or vapor explosion. Depending upon the amount of the melt and the liquid involved, the mechanical energy released during a vapor explosion can be large enough to cause serious destruction. In hypothetical severe accidents which involve fuel melt down, subsequent interactions between the molten fuel and coolant may cause steam explosion. This process has been studied by many investigators in an effort to assess the likelihood of containment failure which leads to large scale release of radioactive materials to the environment. In an effort to understand the phenomenology of steam explosion, extensive studies has been performed so far. The report presents both experimental and analytical studies on steam explosion. As for the experimental studies, both small scale tests which involve usually less than 20 g of high temperature melt and medium/large scale tests which more than 1 kg of melt is used are reviewed. For the modelling part of steam explosions, mechanistic modelling as well as thermodynamic modelling is reviewed. (author)

  20. Water regime of steam power plants

    International Nuclear Information System (INIS)

    Oesz, Janos

    2011-01-01

    The water regime of water-steam thermal power plants (secondary side of pressurized water reactors (PWR); fossil-fired thermal power plants - referred to as steam power plants) has changed in the past 30 years, due to a shift from water chemistry to water regime approach. The article summarizes measures (that have been realised by chemists of NPP Paks) on which the secondary side of NPP Paks has become a high purity water-steam power plant and by which the water chemistry stress corrosion risk of heat transfer tubes in the VVER-440 steam generators was minimized. The measures can also be applied to the water regime of fossil-fired thermal power plants with super- and subcritical steam pressure. Based on the reliability analogue of PWR steam generators, water regime can be defined as the harmony of construction, material(s) and water chemistry, which needs to be provided in not only the steam generators (boiler) but in each heat exchanger of steam power plant: - Construction determines the processes of flow, heat and mass transfer and their local inequalities; - Material(s) determines the minimal rate of general corrosion and the sensitivity for local corrosion damage; - Water chemistry influences the general corrosion of material(s) and the corrosion products transport, as well as the formation of local corrosion environment. (orig.)

  1. Electrocatalytic properties of monometallic and bimetallic nanoparticles-incorporated polypyrrole films for electro-oxidation of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, V.; Alagar, M. [Department of Chemical Engineering, Alagappa College of Technology, Anna University, Chennai 600025 (India); Hamerton, I. [Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2006-10-06

    Oxidative electrochemical polymerization of pyrrole at indium-doped tin oxide (ITO) is accomplished from a neat monomer solution with a supporting electrolyte (0.3M n-tetrabutyl ammonium tetrafluoroborate) by multiple-scan cyclic voltammetry. Polypyrrole (Ppy) films containing nanometer-sized platinum and Pt/Pd bimetallic particles are electro-synthesized on ITO glass plates by voltammetric cycling between -0.1 and +1V (versus Ag/AgCl/3M NaCl). The electrocatalytic oxidation of methanol on the nanoparticle-modified polypyrrole films is studied by means of electrochemical techniques. The modified electrode exhibits significant eletrocatalytic activity for methanol oxidation. The enhanced electrocatalytic activities may be due to the uniform dispersion of nanoparticles in the polypyrrole film and a synergistic effect of the highly-dispersed metal particles so that the polypyrrole film reduces electrode poisoning by adsorbed CO species. The monometallic (Pt) and bimetallic (Pt/Pd) nanoparticles are uniformly dispersed in polypyrrole matrixes, as confirmed by scanning electron microscopic and atomic force microscopic analysis. Energy dispersive X-ray analysis is used to characterize the composition of metal present in the nanoparticle-modified electrodes. (author)

  2. High-speed conversion of carbon dioxide into methanol using catalyst. Shokubai ni yoru nisanka tanso no kosoku methanol ka

    Energy Technology Data Exchange (ETDEWEB)

    Inui, T. (Kyoto University, Kyoto (Japan). Faculty of Enineering)

    1993-02-01

    This paper describes high-speed conversion of CO2 into methanol. When a Cu-Zn-Cr-Al oxide-based catalyst (MSCp catalyst) prepared by using a sedimentation process used for synthesizing methanol from CO is applied to converting CO2 into methanol, the methanol yield decreases down to a several fraction of CO to methanol conversion, with a possibility of greater catalytic deactivation. If this catalyst prepared by using a homogeneous gelation process (MSCg catalyst) is used, the yield of methanol from CO2 increases by 240 plus percent over the case of using the MSCp catalyst, and no catalytic deactivation occurs at all during a use for ten and odd hours. Further, when La2O3 is added to the MSCg catalyst at 4% by weight, the methanol yield increases by about two times as much as the case without addition, and the temperature at which the maximum yield is achieved shifts to a lower temperature side by about 20[degree]C. Combining Ag or Pd with the MSCg catalyst provides the same effects. The paper touches on an attempt of high-speed CO2 conversion using this catalyst loaded with ceramic fibers. 15 refs., 5 figs., 2 tabs.

  3. WABASH RIVER INTEGRATED METHANOL AND POWER PRODUCTION FROM CLEAN COAL TECHNOLOGIES (IMPPCCT)

    Energy Technology Data Exchange (ETDEWEB)

    Doug Strickland; Albert Tsang

    2002-10-14

    The Wabash River Integrated Methanol and Power Production from Clean Coal Technologies (IMPPCCT) project is evaluating integrated electrical power generation and methanol production through clean coal technologies. The project is conducted by a multi-industry team lead by Gasification Engineering Corporation (GEC), and supported by Air Products and Chemicals, Inc., Dow Chemical Company, Dow Corning Corporation, Methanex Corporation, and Siemens Westinghouse Power Corporation. Three project phases are planned for execution over a three year period, including: (1) Feasibility study and conceptual design for an integrated demonstration facility, and for fence-line commercial plants operated at Dow Chemical or Dow Corning chemical plant locations; (2) Research, development, and testing to define any technology gaps or critical design and integration issues; and (3) Engineering design and financing plan to install an integrated commercial demonstration facility at the existing Wabash River Energy Limited (WREL) plant in West Terre Haute, Indiana. This report describes management planning, work breakdown structure development, and feasibility study activities by the IMPPCCT consortium in support of the first project phase. Project planning activities have been completed, and a project timeline and task list has been generated. Requirements for an economic model to evaluate the West Terre Haute implementation and for other commercial implementations are being defined. Specifications for methanol product and availability of local feedstocks for potential commercial embodiment plant sites have been defined. The WREL facility is a project selected and co-funded under the fifth phase solicitation of the U.S. Department of Energy's Clean Coal Technology Program. In this project, coal and/or other solid fuel feedstocks are gasified in an oxygen-blown, entrained-flow gasifier with continuous slag removal and a dry particulate removal system. The resulting product synthesis

  4. Performance comparison of two low-CO2 emission solar/methanol hybrid combined cycle power systems

    International Nuclear Information System (INIS)

    Li, Yuanyuan; Zhang, Na; Lior, Noam

    2015-01-01

    Highlights: • Two novel solar hybrid combined cycle systems have been proposed and analyzed. • The power systems integrate solar-driven thermo-chemical conversion and CO 2 capture. • Exergy efficiency of about 55% and specific CO 2 emissions of 34 g/kW h are predicted. • Systems CO 2 emissions are 36.8% lower compared to a combined cycle with CO 2 capture. • The fossil fuel demand is ∼30% lower with a solar share of ∼20%. - Abstract: Two novel hybrid combined cycle power systems that use solar heat and methanol, and integrate CO 2 capture, are proposed and analyzed, one based on solar-driven methanol decomposition and the other on solar-driven methanol reforming. The high methanol conversion rates at relatively low temperatures offer the advantage of using the solar heat at only 200–300 °C to drive the syngas production by endothermic methanol conversions and its conversion to chemical energy. Pre-combustion decarbonization is employed to produce CO 2 -free fuel from the fully converted syngas, which is then burned to produce heat at the high temperature for power generation in the proposed advanced combined cycle systems. To improve efficiency, the systems’ configurations were based on the principle of cascade use of multiple heat sources of different temperatures. The thermodynamic performance of the hybrid power systems at its design point is simulated and evaluated. The results show that the hybrid systems can attain an exergy efficiency of about 55%, and specific CO 2 emissions as low as 34 g/kW h. Compared to a gas/steam combined cycle with flue gas CO 2 capture, the proposed solar-assisted system CO 2 emissions are 36.8% lower, and a fossil fuel saving ratio of ∼30% is achievable with a solar thermal share of ∼20%. The system integration predicts high efficiency conversion of solar heat and low-energy-penalty CO 2 capture, with the additional advantage that solar heat is at relatively low temperature where its collection is cheaper and

  5. A simple preparation of very high methanol tolerant cathode electrocatalyst for direct methanol fuel cell based on polymer-coated carbon nanotube/platinum.

    Science.gov (United States)

    Yang, Zehui; Nakashima, Naotoshi

    2015-07-20

    The development of a durable and methanol tolerant electrocatalyst with a high oxygen reduction reaction activity is highly important for the cathode side of direct methanol fuel cells. Here, we describe a simple and novel methodology to fabricate a practically applicable electrocatalyst with a high methanol tolerance based on poly[2,2'-(2,6-pyridine)-5,5'-bibenzimidazole]-wrapped multi-walled carbon nanotubes, on which Pt nanoparticles have been deposited, then coated with poly(vinylphosphonic acid) (PVPA). The polymer coated electrocatalyst showed an ~3.3 times higher oxygen reduction reaction activity compared to that of the commercial CB/Pt and methanol tolerance in the presence of methanol to the electrolyte due to a 50% decreased methanol adsorption on the Pt after coating with the PVPA. Meanwhile, the peroxide generation of the PVPA coated electrocatalyst was as low as 0.8% with 2 M methanol added to the electrolyte, which was much lower than those of the non-PVPA-coated electrocatalyst (7.5%) and conventional CB/Pt (20.5%). Such a high methanol tolerance is very important for the design of a direct methanol fuel cell cathode electrocatalyst with a high performance.

  6. Compact Fuel-Cell System Would Consume Neat Methanol

    Science.gov (United States)

    Narayanan, Sekharipuram; Kindler, Andrew; Valdez, Thomas

    2007-01-01

    In a proposed direct methanol fuel-cell electric-power-generating system, the fuel cells would consume neat methanol, in contradistinction to the dilute aqueous methanol solutions consumed in prior direct methanol fuel-cell systems. The design concept of the proposed fuel-cell system takes advantage of (1) electro-osmotic drag and diffusion processes to manage the flows of hydrogen and water between the anode and the cathode and (2) evaporative cooling for regulating temperature. The design concept provides for supplying enough water to the anodes to enable the use of neat methanol while ensuring conservation of water for the whole fuel-cell system.

  7. Moisture separator for steam generator level measurement system

    International Nuclear Information System (INIS)

    Cantineau, B.J.

    1987-01-01

    A steam generator level measurement system having a reference leg which is kept full of water by a condensation pot, has a liquid/steam separator in the connecting line between the condensation pot and the steam phase in the steam generator to remove excess liquid from the steam externally of the steam generator. This ensures that the connecting line does not become blocked. The separator pot has an expansion chamber which slows down the velocity of the steam/liquid mixture to aid in separation, and a baffle, to avoid liquid flow into the line connected to the condensate pot. Liquid separated is returned to the steam generator below the water level through a drain line. (author)

  8. Future development of large steam turbines

    International Nuclear Information System (INIS)

    Chevance, A.

    1975-01-01

    An attempt is made to forecast the future of the large steam turbines till 1985. Three parameters affect the development of large turbines: 1) unit output; and a 2000 to 2500MW output may be scheduled; 2) steam quality: and two steam qualities may be considered: medium pressure saturated or slightly overheated steam (light water, heavy water); light enthalpie drop, high pressure steam, high temperature; high enthalpic drop; and 3) the quality of cooling supply. The largest range to be considered might be: open system cooling for sea-sites; humid tower cooling and dry tower cooling. Bi-fluid cooling cycles should be also mentioned. From the study of these influencing factors, it appears that the constructor, for an output of about 2500MW should have at his disposal the followings: two construction technologies for inlet parts and for high and intermediate pressure parts corresponding to both steam qualities; exhaust sections suitable for the different qualities of cooling supply. The two construction technologies with the two steam qualities already exist and involve no major developments. But, the exhaust section sets the question of rotational speed [fr

  9. Reduction in the microbial load on high-touch surfaces in hospital rooms by treatment with a portable saturated steam vapor disinfection system.

    Science.gov (United States)

    Sexton, Jonathan D; Tanner, Benjamin D; Maxwell, Sheri L; Gerba, Charles P

    2011-10-01

    Recent scientific literature suggests that portable steam vapor systems are capable of rapid, chemical-free surface disinfection in controlled laboratory studies. This study evaluated the efficacy of a portable steam vapor system in a hospital setting. The study was carried out in 8 occupied rooms of a long-term care wing of a hospital. Six surfaces per room were swabbed before and after steam treatment and analyzed for heterotrophic plate count (HPC), total coliforms, methicillin-intermediate and -resistant Staphylococcus aureus (MISA and MRSA), and Clostridium difficile. The steam vapor device consistently reduced total microbial and pathogen loads on hospital surfaces, to below detection in most instances. Treatment reduced the presence of total coliforms on surfaces from 83% (40/48) to 13% (6/48). Treatment reduced presumptive MISA (12/48) and MRSA (3/48) to below detection after cleaning, except for 1 posttreatment isolation of MISA (1/48). A single C difficile colony was isolated from a door push panel before treatment, but no C difficile was detected after treatment. The steam vapor system reduced bacterial levels by >90% and reduced pathogen levels on most surfaces to below the detection limit. The steam vapor system provides a means to reduce levels of microorganisms on hospital surfaces without the drawbacks associated with chemicals, and may decrease the risk of cross-contamination. Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  10. Vapor generator steam drum spray heat

    International Nuclear Information System (INIS)

    Fasnacht, F.A. Jr.

    1978-01-01

    A typical embodiment of the invention provides a combination feedwater and cooldown water spray head that is centrally disposed in the lower portion of a nuclear power plant steam drum. This structure not only discharges the feedwater in the hottest part of the steam drum, but also increases the time required for the feedwater to reach the steam drum shell, thereby further increasing the feedwater temperature before it contacts the shell surface, thus reducing thermal shock to the steam drum structure

  11. The new equation of steam quality and the evaluation of nonradioactive tracer method in PWR steam generators

    International Nuclear Information System (INIS)

    Ki Bang, Sung; Young Jin, Chang

    2001-01-01

    The performance of steam turbines is tested as ANSI/ASME-PTC 6. This code provides rules for the accurate testing of steam turbines for the purpose of obtaining the level of performance with a minimum uncertainty. Only the relevant portion of this code needs to process any individual case, In some case the procedure is simple. However, in complex turbines or complex operation modes, more procedures are required to test the involved provisions. Anyway, to measure the steam quality in the Wolsong PHWR with 4 SGs in Korea by the methods in the section ''Measure of steam quality methods'' of ANSI/ASME PTC 6, the result was not good though the steam generators are efficient. So, the new testing method was developed and the sophisticated equation of steam quality was introduced and uses the nonradioactive chemical tracer, Lithium hydroxide(LiOH) instead of the radioactive tracer, Na-24. (author)

  12. High-temperature oxidation of Zircaloy in hydrogen-steam mixtures

    International Nuclear Information System (INIS)

    Chung, H.M.; Thomas, G.R.

    1982-09-01

    Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700 0 C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam-supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam-supply rate

  13. Thermal hydraulic studies in steam generator test facility

    International Nuclear Information System (INIS)

    Vinod, V.; Suresh Kumar, V.A.; Noushad, I.B.; Ellappan, T.R.; Rajan, K.K.; Rajan, M.; Vaidyanathan, G.

    2005-01-01

    Full text of publication follows: A 500 MWe fast breeder reactor is being constructed at Kalpakkam, India. This is a sodium cooled reactor with two primary and two secondary sodium loops with total 8 steam generators. The typical advantage of fast breeder plants is the high operating temperature of steam cycles and the high plant efficiency. To produce this high pressure and high temperature steam, once through straight tube vertical sodium heated steam generators are used. The steam is generated from the heat produced in the reactor core and being transported through primary and secondary sodium circuits. The steam generator is a 25 m high middle supported steam generator with expansion bend and 23 m heat transfer length. Steam Generator Test Facility (SGTF) constructed at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam aims at performing various tests on a 5.5 MWt steam generator. This vertically simulated test article is similar in all respects to the proposed 157 MWt steam generator module for the Prototype Fast Breeder Reactor (PFBR), with reduced number of tubes. Heat transfer performance tests are done with this 19 tube steam generator at various load conditions. Sodium circuit for the SGTF is equipped with oil fired heater as heat source and centrifugal sodium pump, to pump sodium at 105 m 3 /hr flow rate. Other typical components like sodium to air heat exchanger, sodium purification system and hydrogen leak detection system is also present in the sodium circuit. High pressure steam produced in the steam generator is dumped in a condenser and recycled. Important tests planned in SGTF are the heat transfer performance test, stability test, endurance test and performance test of steam generator under various transients. The controlled operation of steam generator will be studied with possible control schemes. A steady state simulation of the steam generator is done with a mathematical model. This paper gives the details of heat transfer

  14. Improving Steam System Performance: A Sourcebook for Industry

    Energy Technology Data Exchange (ETDEWEB)

    2002-06-01

    The sourcebook is a reference for industrial steam system users, outlining opportunities to improve steam system performance. This Sourcebook is designed to provide steam system users with a reference that describes the basic steam system components, outlines opportunities for energy and performance improvements, and discusses the benefits of a systems approach in identifying and implementing these improvement opportunities. The Sourcebook is divided into the following three main sections: Section 1: Steam System Basics--For users unfamiliar with the basics of steam systems, or for users seeking a refresher, a brief discussion of the terms, relationships, and important system design considerations is provided. Users already familiar with industrial steam system operation may want to skip this section. This section describes steam systems using four basic parts: generation, distribution, end use, and recovery. Section 2: Performance Improvement Opportunities--This section discusses important factors that should be considered when industrial facilities seek to improve steam system performance and to lower operating costs. This section also provides an overview of the finance considerations related to steam system improvements. Additionally, this section discusses several resources and tools developed by the U. S. Department of Energy's (DOE) BestPractices Steam Program to identify and assess steam system improvement opportunities. Section 3: Programs, Contacts, and Resources--This section provides a directory of associations and other organizations involved in the steam system marketplace. This section also provides a description of the BestPractices Steam Program, a directory of contacts, and a listing of available resources and tools, such as publications, software, training courses, and videos.

  15. Steam purity in PWRs

    International Nuclear Information System (INIS)

    Hopkinson, J.; Passell, T.

    1982-01-01

    Reports that 2 EPRI studies of PWRs prove that impure steam triggers decay of turbine metals. Reveals that EPRI is attempting to improve steam monitoring and analysis, which are key steps on the way to deciding the most cost-effective degree of steam purity, and to upgrade demineralizing systems, which can then reliably maintain that degree of purity. Points out that 90% of all cracks in turbine disks have occurred at the dry-to-wet transition zone, dubbed the Wilson line. Explains that because even very clean water contains traces of chemical impurities with concentrations in the parts-per-billion range, Crystal River-3's secondary loop was designed with even more purification capability; a deaerator to remove oxygen and prevent oxidation of system metals, and full-flow resin beds to demineralize 100% of the secondary-loop water from the condenser. Concludes that focusing attention on steam and water chemistry can ward off cracking and sludge problems caused by corrosion

  16. Conversion of Methane into Methanol and Ethanol over Nickel Oxide on Ceria-Zirconia Catalysts in a Single Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Okolie, Chukwuemeka [School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW Atlanta GA 30332 USA; Belhseine, Yasmeen F. [School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW Atlanta GA 30332 USA; Lyu, Yimeng [School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW Atlanta GA 30332 USA; Yung, Matthew M. [National Renewable Energy Laboratory, Golden CO 80401 USA; Engelhard, Mark H. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Lab, Richland WA 99354 USA; Kovarik, Libor [Environmental Molecular Sciences Laboratory, Pacific Northwest National Lab, Richland WA 99354 USA; Stavitski, Eli [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton NY 11973 USA; Sievers, Carsten [School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive NW Atlanta GA 30332 USA

    2017-09-26

    Direct conversion of methane into alcohols is a promising technology for converting stranded methane reserves into liquids that can be transported in pipelines and upgraded to value-added chemicals. We demonstrate that a catalyst consisting of small nickel oxide clusters supported on ceria-zirconia (NiO/CZ) can selectively oxidize methane to methanol and ethanol in a single, steady-state process at 723 K using O2 as an abundantly available oxidant. The presence of steam is required to obtain alcohols rather than CO2 as the product of catalytic combustion. The unusual activity of this catalyst is attributed to the synergy between the small Lewis acidic NiO clusters and the redox-active CZ support, which also stabilizes the small NiO clusters.

  17. Kids Inspire Kids for STEAM

    OpenAIRE

    Fenyvesi, Kristof; Houghton, Tony; Diego-Mantecón, José Manuel; Crilly, Elizabeth; Oldknow, Adrian; Lavicza, Zsolt; Blanco, Teresa F.

    2017-01-01

    Abstract The goal of the Kids Inspiring Kids in STEAM (KIKS) project was to raise students' awareness towards the multi- and transdisciplinary connections between the STEAM subjects (Science, Technology, Engineering, Arts & Mathematics), and make the learning about topics and phenomena from these fields more enjoyable. In order to achieve these goals, KIKS project has popularized the STEAM-concept by projects based on the students inspiring other students-approach and by utilizing new tec...

  18. Electrochemical measurements in PWR steam generators to follow crevice chemistry

    International Nuclear Information System (INIS)

    Feron, D.

    1991-01-01

    In PWR steam generator crevices, the evolution of chemistry is important for the understanding of corrosion phenomena. Electrochemical measurements have been performed in high temperature simulated crevice environments in order to follow hideout processes and remedial actions (on-line addition of boric acid). Reported tests have been conducted with model boilers of AJAX facilities. Eccentric and concentric tube support plate crevices have been instrumented with platinum electrodes. Electrochemical measurements have been collected when model boiler was under nominal conditions (primary temperature: 335 deg C, secondary temperature: 280 deg C). They include Electrochemical Impedance Spectroscopy (EIS) and potential measurements: with EIS, sodium and boric acid hideouts have been detected and followed. Potential measurements have been performed in an attempt to measure crevice PH evolution

  19. CAREM-25 Steam Generator Stability Analysis

    International Nuclear Information System (INIS)

    Rabiti, A.; Delmastro, D.

    2003-01-01

    In this work the stability of a once-through CAREM-25 steam generator is analyzed.A fix nodes numerical model, that allows the modelling of the liquid, two-phase and superheated steam zones, is implemented.This model was checked against a mobile finite elements model under saturated steam conditions at the channel exit and a good agreement was obtained.Finally the stability of a CAREM steam generator is studied and the range of in let restrictions that a assure the system stability is analyzed

  20. Nitrofurantoin methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Venu R. Vangala

    2011-03-01

    Full Text Available The antibiotic nitrofurantoin {systematic name: (E-1-[(5-nitro-2-furylmethylideneamino]imidazolidine-2,4-dione} crystallizes as a methanol monosolvate, C8H6N4O5·CH4O. The nitrofurantoin molecule adopts a nearly planar conformation (r.m.s. deviation = 0.0344 Å. Hydrogen bonds involve the co-operative N—H...O—H...O heterosynthons between the cyclic imide of nitrofurantoin and methanol O—H groups. There are also C—H...O hydrogen bonds involving the nitrofurantoin molecules which support the key hydrogen-bonding synthon. The overall crystal packing is further assisted by weak C—H...O interactions, giving a herringbone pattern.

  1. 46 CFR 61.15-5 - Steam piping.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam piping. 61.15-5 Section 61.15-5 Shipping COAST... Periodic Tests of Piping Systems § 61.15-5 Steam piping. (a) Main steam piping shall be subjected to a... removed and the piping thoroughly examined. (b) All steam piping subject to pressure from the main boiler...

  2. Methanol suppression of trichloroethylene degradation by M. trichosporium

    International Nuclear Information System (INIS)

    Palumbo, A.V.; Eng, W.

    1990-01-01

    Biodegradation by methylotrophs has been considered a potential method for in situ remediation, but delivery of sufficient methane could be a problem. Since methanol could be delivered more readily into soil, the authors examined TCE degradation under methane (0.89 M), methanol (1.187 mM), and combined methane (0.89 mM) methanol (1.187 mM) stimulated treatments using M. trichosporium and mixed cultures JS and DT. Degradation of TCE was determined by the summation of radiolabeled CO 2 , water-soluble intermediates, and biomass transformed from 14 C TCE. M. trichosporium degraded 0.36 ± 2.08% (mean ± std dev) of the initial TCe (0.3 mg/l) with methanol stimulation, compared to 9.07 ± 1.04% with methane stimulation. JS and DT cultures degraded 4.34 ± 0.11% on methanol compared to 24.3 ± 1.38% and 34.3 ± 3.0% on methane, respectively. If methanol was added to methane-stimualted cultures, TCE degradation was reduced to 1.08 ± 1.74% for M. trichosporium, and 5.08 ± 0.56% for JS culture. Methanol retarded the rates of methane and oxygen utilization as well. However, methanol-stimulated cultures grew to a greater extent than methane-stimulated cultures with 14 mg/l TCE. Previous workers have shown that methanol suppresses methane monooxygenase, and they suggest this may explain the reduced amount of TCE degraded

  3. Steampunk: Full Steam Ahead

    Science.gov (United States)

    Campbell, Heather M.

    2010-01-01

    Steam-powered machines, anachronistic technology, clockwork automatons, gas-filled airships, tentacled monsters, fob watches, and top hats--these are all elements of steampunk. Steampunk is both speculative fiction that imagines technology evolved from steam-powered cogs and gears--instead of from electricity and computers--and a movement that…

  4. Methanol production from eucalyptus wood chips. Attachment IV. Health and safety aspects of the eucalypt biomass to methanol energy system

    Energy Technology Data Exchange (ETDEWEB)

    Fishkind, H.H.

    1982-06-01

    The basic eucalyptus-to-methanol energy process is described and possible health and safety risks are identified at all steps of the process. The toxicology and treatment for exposure to these substances are described and mitigating measures are proposed. The health and safety impacts and risks of the wood gasification/methanol synthesis system are compared to those of the coal liquefaction and conversion system. The scope of this report includes the health and safety risks of workers (1) in the laboratory and greenhouse, where eucalyptus seedlings are developed, (2) at the biomass plantation, where these seedlings are planted and mature trees harvested, (3) transporting these logs and chips to the refinery, (4) in the hammermill, where the logs and chips will be reduced to small particles, (5) in the methanol synthesis plant, where the wood particles will be converted to methanol, and (6) transporting and dispensing the methanol. Finally, the health and safety risks of consumers using methanol is discussed.

  5. Methanol production from Eucalyptus wood chips. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fishkind, H.H.

    1982-06-01

    This feasibility study includes all phases of methanol production from seedling to delivery of finished methanol. The study examines: production of 55 million, high quality, Eucalyptus seedlings through tissue culture; establishment of a Eucalyptus energy plantation on approximately 70,000 acres; engineering for a 100 million gallon-per-day methanol production facility; potential environmental impacts of the whole project; safety and health aspects of producing and using methanol; and development of site specific cost estimates.

  6. 7 CFR 29.3058 - Steam-dried.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.3058 Section 29.3058 Agriculture... Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [24 FR 8771, Oct. 29, 1959. Redesignated at 47 FR...

  7. Steam atmosphere drying concepts using steam exhaust recompression

    Energy Technology Data Exchange (ETDEWEB)

    DiBella, F.A. (TECOGEN, Inc., Waltham, MA (United States))

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg[sub evap] to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  8. Steam atmosphere drying concepts using steam exhaust recompression

    Energy Technology Data Exchange (ETDEWEB)

    DiBella, F.A. [TECOGEN, Inc., Waltham, MA (United States)

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg{sub evap} to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  9. Cycle improvement for nuclear steam power plant

    International Nuclear Information System (INIS)

    Silvestri, G.J. Jr.

    1976-01-01

    A pressure-increasig ejector element is disposed in an extraction line intermediate to a high pressure turbine element and a feedwater heater. The ejector utilizes high pressure fluid from a reheater drain as the motive fluid to increase the pressure at which the extraction steam is introduced into the feedwater heater. The increase in pressure of the extraction steam entering the feedwater heater due to the steam passage through the ejector increases the heat exchange capability of the extraction steam thus increasing the overall steam power plant efficiency

  10. Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells.

    Science.gov (United States)

    Kim, Jiyoung; Jang, Jin-Sung; Peck, Dong-Hyun; Lee, Byungrok; Yoon, Seong-Ho; Jung, Doo-Hwan

    2016-08-15

    Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF) was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC). The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR) activities and the electrochemical double layer compared with common carbon black (CB). To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF. The physical and electrochemical characteristics of the N-CNF-supported Pt-Pd catalyst were examined and compared with catalyst supported on the CB. In addition, DMFC single cells using these catalysts as the cathode electrode were applied to obtain I-V polarization curves and constant current operating performances with high-concentration methanol as the fuel. Pt-Pd catalysts had obvious ORR activity even in the presence of methanol. The higher power density was obtained at all the methanol concentrations when it applied to the membrane electrode assembly (MEA) of the DMFC. When the N-CNF is used as the catalyst support material, a better performance with high-concentration methanol is expected.

  11. Methanol-Tolerant Platinum-Palladium Catalyst Supported on Nitrogen-Doped Carbon Nanofiber for High Concentration Direct Methanol Fuel Cells

    Directory of Open Access Journals (Sweden)

    Jiyoung Kim

    2016-08-01

    Full Text Available Pt-Pd catalyst supported on nitrogen-doped carbon nanofiber (N-CNF was prepared and evaluated as a cathode electrode of the direct methanol fuel cell (DMFC. The N-CNF, which was directly synthesized by the catalytic chemical vapor deposition from acetonitrile at 640 °C, was verified as having a change of electrochemical surface properties such as oxygen reduction reaction (ORR activities and the electrochemical double layer compared with common carbon black (CB. To attain the competitive oxygen reduction reaction activity with methanol tolerance, the Pt and Pd metals were supported on the CB or the N-CNF. The physical and electrochemical characteristics of the N-CNF–supported Pt-Pd catalyst were examined and compared with catalyst supported on the CB. In addition, DMFC single cells using these catalysts as the cathode electrode were applied to obtain I-V polarization curves and constant current operating performances with high-concentration methanol as the fuel. Pt-Pd catalysts had obvious ORR activity even in the presence of methanol. The higher power density was obtained at all the methanol concentrations when it applied to the membrane electrode assembly (MEA of the DMFC. When the N-CNF is used as the catalyst support material, a better performance with high-concentration methanol is expected.

  12. Amazing & extraordinary facts the steam age

    CERN Document Server

    Holland, Julian

    2012-01-01

    Respected transport author Julian Holland delves into the intriguing world of steam in his latest book, which is full of absorbing facts and figures on subjects ranging from Cornish beam engines, steam railway locomotives, road vehicles and ships through to traction engines, steam rollers and electricity generating stations and the people who designed and built them. Helped along the way by the inventive minds of James Watt, Richard Trevithick and George Stephenson, steam became the powerhouse that drove the Industrial Revolution in Britain in the late 18th and 19th centuries.

  13. Internal ultrasonic testing of steam generator tubes

    International Nuclear Information System (INIS)

    Furlan, J.; Soleille, G.; Chalaye, H.

    1983-01-01

    The ''in situ'' inspection of steam generator tubes uses generally Foucault currents before starting and along its life. This inspection aims at searching cracks and corrosion defects. The Foucault current method is quite badly adapted to ''closed crack'' detection, for it doesn't introduce neither resistivity or magnetic permeability variation, or lack of matter. More, it is sensible to the magnetic properties of the tube itself and to its environment (tubular or support plates). It is why, this first systematic inspection has to be completed by an ultrasonic one allowing to bring new elements in the uncertain cases. A device with an internal probe has been developed. It ''lights'' the tube wall with the aid of a transducer of which beam reflects on a mirror. Operating conditions are the same as for Foucault current testing, that is to say the probe moves inside the tube without rotation of the device (bent parts are excluded) [fr

  14. World scale fuel methanol facility siting

    International Nuclear Information System (INIS)

    Stapor, M.C.; Hederman, W.F.

    1990-01-01

    Since the Administration announced a clean alternative fuels initiative, industry and government agencies' analyses of the economics of methanol as an alternative motor vehicle fuel have accelerated. In the short run, methanol appears attractive because excess production capacity currently has depressed methanol prices and marginal costs of production are lower than other fuels (current excess capacity). In the long run, however, full costs are the more relevant. To lower average production costs, U.S. policy interest has focused on production from a world-scale, 10,000 tons per day (tpd) methanol plant facility on a foreign site. This paper reviews several important site and financial considerations in a framework to evaluate large scale plant development. These considerations include: risks associated with a large process plant; supply economics of foreign sites; and investment climates and financial incentives for foreign investment at foreign sites

  15. 7 CFR 29.2552 - Steam-dried.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.2552 Section 29.2552 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2552 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam...

  16. 7 CFR 29.2300 - Steam-dried.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.2300 Section 29.2300 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2300 Steam... machine or other steam-conditioning equipment. [37 FR 13521, July 11, 1972. Redesignated at 51 FR 40406...

  17. 7 CFR 29.3548 - Steam-dried.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.3548 Section 29.3548 Agriculture... Type 95) § 29.3548 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [30 FR 9207, July 23, 1965...

  18. 7 CFR 29.1060 - Steam-dried.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.1060 Section 29.1060 Agriculture... Type 92) § 29.1060 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [42 FR 21092, Apr. 25, 1977...

  19. A rare presentation of methanol toxicity

    Directory of Open Access Journals (Sweden)

    Nikhil Gupta

    2013-01-01

    Full Text Available Methanol is a highly toxic alcohol resembling ethanol in smell and taste. Methanol poisoning is a lethal form of poisoning that can cause severe metabolic acidosis, visual disturbances, and neurological deficit. Brain lesions typically described in methanol toxicity are in the form of hemorrhagic and non-hemorrhagic necrosis of the basal ganglia and sub-cortical white matter. To our knowledge, lesions in the parietal, temporal, or frontal areas of cerebrum and cerebellar hemispheres have been rarely reported so far. We herewith report this rare presentation.

  20. Device to position selectively a tool carried by a vehicle moving on the perforated plate of a tube bundle

    International Nuclear Information System (INIS)

    Bernardin, M.

    1985-01-01

    The aim of the invention is an examination device for a tube bundle of an apparatus such as, but not restrictively, a steam generator, situated in a dangerous zone, e.g. radioactive and designed to be introduced into the water box of the said and placed against the perforated plate of the tube bundle by an operator working outside of the said apparatus and able to operate whatever the vertical or horizontal position of the tube plate. The device has a selectively positionable tool - carrying vehicle comprising pistons positioning fingers extendable into the tubes and mounted on extendable supports perpendicular to the pistons and to each other, and an articulated telescopic arm fixed at one end to a rotary mounting on the vehicle and at the other end to an access opening in the vessel containing the tube plate, to hold the vehicle against the plate [fr

  1. Process and device for locating a defective tube, particularly in the tube bundle of a steam generator

    International Nuclear Information System (INIS)

    Denis, Jean.

    1977-01-01

    A process is described for locating a defective tube, particularly in the tube bundle of a steam generator of the reversed U tube kind with the ends connected to a tube plate, marking with the bottom of the generator casing a space separated into two adjacent collectors, respectively for the inlet and outlet of a primary fluid flowing inside the tubes of the bundle, these being externally washed by a secondary vaporizing fluid. In this process a television camera that can be inserted into the casing is used. This process consists in transmitting to a display system outside the generator an image of the tube plate in each collector by means of a directional television camera and then to place over this image a luminous marker to locate the end or the faulty tube [fr

  2. Steam generating system in LMFBR type reactors

    International Nuclear Information System (INIS)

    Kurosawa, Katsutoshi.

    1984-01-01

    Purpose: To suppress the thermal shock loads to the structures of reactor system and secondary coolant system, for instance, upon plant trip accompanying turbine trip in the steam generation system of LMFBR type reactors. Constitution: Additional feedwater heater is disposed to the pipeway at the inlet of a steam generator in a steam generation system equipped with a closed loop extended from a steam generator by way of a gas-liquid separator, a turbine and a condensator to the steam generator. The separated water at high temperature and high pressure from a gas-liquid separator is heat exchanged with coolants flowing through the closed loop of the steam generation system in non-contact manner and, thereafter, introduced to a water reservoir tank. This can avoid the water to be fed at low temperature as it is to the steam generator, whereby the thermal shock loads to the structures of the reactor system and the secondary coolant system can be suppressed. (Moriyama, K.)

  3. Spanish approach to research and development applied to steam generator tubes structural integrity and life management

    International Nuclear Information System (INIS)

    Lozano, J.; Bollini, G.J.

    1997-01-01

    The operating experience acquired from certain Spanish Nuclear Power Plant steam generators shows that the tubes, which constitute the second barrier to release of fission products, are susceptible to mechanical damage and corrosion as a result of a variety of mechanisms, among them wastage, pitting, intergranular attack (IGA), stress-corrosion cracking (SCC), fatigue-induced cracking, fretting, erosion/corrosion, support plate denting, etc. These problems, which are common in many plants throughout the world, have required numerous investments by the plants (water treatment plants, replacement of secondary side materials such as condensers and heaters, etc.), have meant costs (operation, inspection and maintenance) and have led to the unavailability of the affected units. In identifying and implementing all these preventive and corrective measures, the Spanish utilities have moved through three successive stages: in the initial stage, the main source of information and of proposals for solutions was the Plant Vendor, whose participation in this respect was based on his own Research and Development programs; subsequently, the Spanish utilities participated jointly in the EPRI Steam Generator Owners Group, collaborating in financing; finally, the Spanish utilities set up their own Steam Generator Research and Development program, while maintaining relations with EPRI programs and those of other countries through information interchange

  4. Circumferential cracking of steam generator tubes

    International Nuclear Information System (INIS)

    Karwoski, K.J.

    1997-04-01

    On April 28, 1995, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 95-03, open-quote Circumferential Cracking of Steam Generator Tubes.close-quote GL 95-03 was issued to obtain information needed to verify licensee compliance with existing regulatory requirements regarding the integrity of steam generator tubes in domestic pressurized-water reactors (PWRs). This report briefly describes the design and function of domestic steam generators and summarizes the staff's assessment of the responses to GL 95-03. The report concludes with several observations related to steam generator operating experience. This report is intended to be representative of significant operating experience pertaining to circumferential cracking of steam generator tubes from April 1995 through December 1996. Operating experience prior to April 1995 is discussed throughout the report, as necessary, for completeness

  5. Efficiency of defect specific maintenance od steam generator tubes: the case of ODSCC

    International Nuclear Information System (INIS)

    Cizelj, L.; Dvorsek, T.

    1996-01-01

    The outside diameter stress corrosion cracking at tube support plates became the dominating ageing mechanism in steam generators tubes made of Inconel 600. A variety of maintenance approaches were developed and implemented worldwide to deal with this mechanism. Despite different philosophical and physical backgrounds implemented, all of the applied approaches satisfy the relevant regulatory requirements. For our purpose, the maintenance approach consist of: (1) inspection of tubes, (2) accepting or rejecting the defective tube and (3) plugging of rejected tubes. The problem of selecting an optimal maintenance approach is raised in the paper. Consequently, a method comparing the efficiency of applicable maintenance approaches is proposed. The efficiency is defined by three parameters: (a) number of plugged tubes, (b) probability of steam generator tube rupture and (c) predicted accidental leak rates through the defects. An original probabilistic model is proposed to quantify the probability of tube rupture, while procedures available in literature were used to define the accidental leak rates. The numerical example considers the data from Krsko NPP (Westinghouse 632 MWe). The maintenance approaches analyzed include: (i) no repair at all, (ii) traditional defect depth (40%) based maintenance, (iii) alternate plugging criterion (bobbin coil voltage as defined by EPRI and U.S. NRC) and (iv) combined traditional and alternate approach. Advantages of the defect specific approaches (iii) and (iv) over the traditional one (defect depth) are clearly shown. A brief discussion on the optimization of safe life of steam generator is given. (author)

  6. Anti vibration bars replacement in Vandellos II steam generators

    International Nuclear Information System (INIS)

    Vinyes, R.; Leal, R.

    1994-01-01

    C.N. Vandellos II is equipped with three steam generators Westinghouse model F. The number of tubes is 5626 each SG and the material Inconel 600TT. During the first inservice inspection, in 1989, tube wall thickness reductions were observed due to fretting in zones of contact with the tubes anti vibration bars. In the 2 nd shutdown for refueling (1990) all the tubes subject to this type of degradation were inspected by eddy currents, occurring a significative increase in number of tubes affected as well as the quantity of plugged tubes for that reason. Additionally, Westinghouse performed visual inspection and dimensional control of gaps in the tube bundles. Taking in account the results, the replacement with AVBs of new design was decided. AVBs new design is more complex than the original due to the combination of flexible and expandable bars in order to eliminate gaps between tubes an bars an assure proper bundle support. Given that the installation has to be done under water for shielding, all unions are bolted so that no welding is required. Each one of the bars, 333 per SG, is attached to a support structure consisting in 6 retaining plates and 4 bridge plates. (Author)

  7. Options for Steam Generator Decommissioning

    International Nuclear Information System (INIS)

    Krause, Gregor; Amcoff, Bjoern; Robinson, Joe

    2016-01-01

    Selecting the best option for decommissioning steam generators is a key consideration in preparing for decommissioning PWR nuclear power plants. Steam Generators represent a discrete waste stream of large, complex items that can lend themselves to a variety of options for handling, treatment, recycling and disposal. Studsvik has significant experience in processing full size Steam Generators at its metal recycling facility in Sweden, and this paper will introduce the Studsvik steam generator treatment concept and the results achieved to date across a number of projects. The paper will outline the important parameters needed at an early stage to assess options and to help consider the balance between off-site and on-site treatment solutions, and the role of prior decontamination techniques. The paper also outlines the use of feasibility studies and demonstration projects that have been used to help customers prepare for decommissioning. The paper discusses physical, radiological and operational history data, Pro and Contra factors for on- and off-site treatment, the role of chemical decontamination prior to treatment, planning for off-site shipments as well as Studsvik experience This paper has an original focus upon the coming challenges of steam generator decommissioning and potential external treatment capacity constraints in the medium term. It also focuses on the potential during operations or initial shut-down to develop robust plans for steam generator management. (authors)

  8. Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak

    Science.gov (United States)

    Choi, Yun-Sang; Kim, Young-Boong; Jeon, Ki-Hong; Kim, Eun-Mi; Sung, Jung-Min; Kim, Hyun-Wook

    2016-01-01

    The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (pcooked chicken steak was lower than that in the other cooking treatments (pchicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak. PMID:27499656

  9. Determination of moisture content in steams and variation in moisture content with operating boiler level by analyzing sodium content in steam generator water and steam condensate of a nuclear power plant using ion chromatographic technique

    International Nuclear Information System (INIS)

    Pal, P.K.; Bohra, R.C.

    2015-01-01

    Dry steam with moisture content less than <1% is the stringent requirements in a steam generator for good health of the turbine. In order to confirm the same, determination of sodium is done in steam generator water and steam condensate using Flame photometer in ppm level and ion chromatograph in ppb level. Depending on the carry over of sodium in steam along with the water droplet (moisture), the moisture content in steam was calculated and was found to be < 1% which is requirements of the system. The paper described the salient features of a PHWR, principle of Ion Chromatography, chemistry parameters of Steam Generators and calculation of moisture content in steam on the basis of sodium analysis. (author)

  10. Reciprocating wear in a steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.J.; Gee, M.G. [National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2010-07-01

    Tests to simulate the wear between sliding components in steam power plant have been performed using a low frequency wear apparatus at elevated temperatures under static load, at ambient pressure, in a steam environment. The apparatus was modified to accept a novel method of steam delivery. The materials tested were pre-exposed in a flowing steam furnace at temperature for either 500 or 3000 hours to provide some simulation of long term ageing. The duration of each wear test was 50 hours and tests were also performed on as-received material for comparison purposes. Data has been compared with results of tests performed on non-oxidised material for longer durations and also on tests without steam to examine the effect of different environments. Data collected from each test consists of mass change, stub height measurement and friction coefficient as well as visual inspection of the wear track. Within this paper, it is reported that both pre-ageing and the addition of steam during testing clearly influence the friction between material surfaces. (orig.)

  11. Reconstruction of steam generators super emergency feadwater supply system (SHNC) and steam dump stations to the atmosphere system PSA

    International Nuclear Information System (INIS)

    Kuzma, J.

    2001-01-01

    Steam Generators Super Emergency Feadwater Supply System (SHNC) and Steam Dump Stations to the Atmosphere System (PSA) are two systems which cooperate to remove residual heat from reactor core after seismic event. SHNC assure feeding of the secondary site of steam generator (Feed) where after heat removal.from primary loops, is relieved to the atmosphere by PSA (Bleed) in form of steam. (author)

  12. Methanol adsorption on Pt(111)

    International Nuclear Information System (INIS)

    Melo, A.V.; Chottiner, G.S.; Hoffman, R.W.; O'Grady, W.E.

    1984-12-01

    High resolution electron energy loss spectroscopy has been used to study the decomposition of methanol on a Pt(111) surface. Several intermediate states in the decomposition are identified by quenching the sample when reactions occur. At 100 K a set of peaks at 800, 1040, 1350, and 2890 cm -1 indicates the presence of a multilayer molecularly adsorbed methanol. As the sample is warmed to 130 K peaks develop at 1700 and 2780 cm -1 , suggesting the formation of formaldehyde on the surface. With further heating, peaks grow at 1820 and 2560 cm -1 due to the formation of a formyl species during the decomposition of methanol over Pt(111). Further heating leads to the final conversion of the surface species to adsorbed CO and carbonaceous residues

  13. Thermal performances of molten salt steam generator

    International Nuclear Information System (INIS)

    Yuan, Yibo; He, Canming; Lu, Jianfeng; Ding, Jing

    2016-01-01

    Highlights: • Thermal performances of molten salt steam generator were experimentally studied. • Overall heat transfer coefficient reached maximum with optimal molten salt flow rate. • Energy efficiency first rose and then decreased with salt flow rate and temperature. • Optimal molten salt flow rate and temperature existed for good thermal performance. • High inlet water temperature benefited steam generating rate and energy efficiency. - Abstract: Molten salt steam generator is the key technology for thermal energy conversion from high temperature molten salt to steam, and it is used in solar thermal power station and molten salt reactor. A shell and tube type molten salt steam generator was set up, and its thermal performance and heat transfer mechanism were studied. As a coupling heat transfer process, molten salt steam generation is mainly affected by molten salt convective heat transfer and boiling heat transfer, while its energy efficiency is also affected by the heat loss. As molten salt temperature increased, the energy efficiency first rose with the increase of heat flow absorbed by water/steam, and then slightly decreased for large heat loss as the absorbed heat flow still rising. At very high molten salt temperature, the absorbed heat flow decreased as boiling heat transfer coefficient dropping, and then the energy efficiency quickly dropped. As the inlet water temperature increased, the boiling region in the steam generator remarkably expanded, and then the steam generation rate and energy efficiency both rose with the overall heat transfer coefficient increasing. As the molten salt flow rate increased, the wall temperature rose and the boiling heat transfer coefficient first increased and then decreased according to the boiling curve, so the overall heat transfer coefficient first increased and then decreased, and then the steam generation rate and energy efficiency of steam generator both had maxima.

  14. HTGR power plant hot reheat steam pressure control system

    International Nuclear Information System (INIS)

    Braytenbah, A.S.; Jaegtnes, K.O.

    1975-01-01

    A control system for a high temperature gas cooled reactor (HTGR) power plant is disclosed wherein such plant includes a plurality of steam generators. Dual turbine-generators are connected to the common steam headers, a high pressure element of each turbine receiving steam from the main steam header, and an intermediate-low pressure element of each turbine receiving steam from the hot reheat header. Associated with each high pressure element is a bypass line connected between the main steam header and a cold reheat header, which is commonly connected to the high pressure element exhausts. A control system governs the flow of steam through the first and second bypass lines to provide for a desired minimum steam flow through the steam generator reheater sections at times when the total steam flow through the turbines is less than such minimum, and to regulate the hot reheat header steam pressure to improve control of the auxiliary steam turbines and thereby improve control of the reactor coolant gas flow, particularly following a turbine trip. (U.S.)

  15. UK status report on detection and localisation of leaks in steam generators of liquid metal fast breeder reactors

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, J A [Dounreay Nuclear Power Development Establishment, Caithness, Scotland (United Kingdom)

    1978-10-01

    The development of detection and location techniques applied to defects in sodium heated steam generators in Uk has been associated primarily with the PFR commissioning program. The UK position on leak detection and location studies for LMFBR steam generators may be briefly summarised as follows: a) The Initial concept of' detection using hydrogen concentration measuring equipment in secondary circuit sodium and in steam generator gas spaces has proved sound. The system used on the PFR has been shown to work well under plant conditions in both the under sodium and gas phase modes. b) Experience with small leaks in tube to tube plate welds in the PFR steam generators has indicated the majority of leaks would be detected by the installed equipment. There is, however, a very small possibility an under sodium leak in. a ferritic tube which will quickly and easily block may not be detected before it erupts as a relatively significant defect. Methods are being sought to protect against this unlikely event, although it is recognised there is no reactor hazard but there may be a plant availability problem. c) It is concluded the single barrier concept is still valid, based on the experience in the PFR steam generator units. For future units it is intended to use ferritic boiler tube materials rather than austenitic materials. In general, however, it is concluded the material choice has been satisfactory and manufacturing methods are basically sound. Improved quality assurance methods are being sought with the aim of making future steam generators more reliable than those presently in service. d) It is recognised steam generators are still in a development regime in all countries of the world working in the LMFBR field, but the time is anticipated when a utility can order an LMFBR as a commercial proposition. An attempt has been made to quantify the information necessary to achieve this state.

  16. Protein denaturation and functional properties of Lenient Steam Injection heat treated whey protein concentrate

    DEFF Research Database (Denmark)

    Dickow, Jonatan Ahrens; Kaufmann, Niels; Wiking, Lars

    2012-01-01

    Whey protein concentrate (WPC) was heat treated by use of the novel heat treatment method of Lenient Steam Injection (LSI) to elucidate new functional properties in relation to heat-induced gelation of heat treated WPC. Denaturation was measured by both DSC and FPLC, and the results of the two...... methods were highly correlated. Temperatures of up to 90 °C were applicable using LSI, whereas only 68 °C could be reached by plate heat exchange before coagulation/fouling. Denaturation of whey proteins increased with increasing heat treatment temperature up to a degree of 30–35% denaturation at 90 °C...

  17. Model of reverse steam generator

    International Nuclear Information System (INIS)

    Malasek, V.; Manek, O.; Masek, V.; Riman, J.

    1987-01-01

    The claim of Czechoslovak discovery no. 239272 is a model designed for the verification of the properties of a reverse steam generator during the penetration of water, steam-water mixture or steam into liquid metal flowing inside the heat exchange tubes. The design may primarily be used for steam generators with a built-in inter-tube structure. The model is provided with several injection devices configured in different heat exchange tubes, spaced at different distances along the model axis. The design consists in that between the pressure and the circumferential casings there are transverse partitions and that in one chamber consisting of the circumferential casings, pressure casing and two adjoining partitions there is only one passage of the injection device through the inter-tube space. (Z.M.). 1 fig

  18. ( Asteraceae ) methanol extracts against Helicobacter pylori

    African Journals Online (AJOL)

    Methanol vehicle did not affect H. pylori growth. Conclusion: The observed antibacterial effect of G. glutinosum extracts may be of benefit as an adjuvant treatment of diseases caused by H. pylori. Key words: Gymnosperma glutinosum, Helicobacter pylori, methanol extract, minimal inhibitory concentration (MIC).

  19. Minimize corrosion degradation of steam generator tube materials

    International Nuclear Information System (INIS)

    Lu, Y.

    2006-01-01

    As part of a coordinated program, AECL is developing a set of tools to aid with the prediction and management of steam generator performance. Although stress corrosion cracking (of Alloy 800) has not been detected in any operating steam generator, for life management it is necessary to develop mechanistic models to predict the conditions under which stress corrosion cracking is plausible. Experimental data suggest that all steam generator tube materials are susceptible to corrosion degradation under some specific off-specification conditions. The tolerance to the chemistry upset for each steam generator tube alloy is different. Electrochemical corrosion behaviors of major steam generator tube alloys were studied under the plausible aggressive crevice chemistry conditions. The potential hazardous conditions leading to steam generator tube degradation and the conditions, which can minimize steam generator tube degradation have been determined. Recommended electrochemical corrosion potential/pH zones were defined for all major steam generator tube materials, including Alloys 600, 800, 690 and 400, under CANDU steam generator operating and startup conditions. Stress corrosion cracking tests and accelerated corrosion tests were carried out to verify and revise the recommended electrochemical corrosion potential/pH zones. Based on this information, utilities can prevent steam generator material degradation surprises by appropriate steam generator water chemistry management and increase the reliability of nuclear power generating stations. (author)

  20. UO2 production process with methanol washing

    International Nuclear Information System (INIS)

    Sondermann, T.

    1978-01-01

    The invention refers to a process for the recovery of methanol used for washing the ammonium uranyl carbonate obtained during UO 2 production. The methanol contains about 50% H 2 O, about 10% (NH 4 ) 2 CO 3 , and is radioactive. According to the invention the methanol is purified at reduced pressure in a distillation unit and then led back to the washing unit. (UWI) 891 HP/UWI 892 MBE [de