WorldWideScience

Sample records for alkali electrolysis process

  1. Hydrothermal alkali metal recovery process

    Science.gov (United States)

    Wolfs, Denise Y.; Clavenna, Le Roy R.; Eakman, James M.; Kalina, Theodore

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by treating them with a calcium or magnesium-containing compound in the presence of water at a temperature between about 250.degree. F. and about 700.degree. F. and in the presence of an added base to establish a pH during the treatment step that is higher than would otherwise be possible without the addition of the base. During the treating process the relatively high pH facilitates the conversion of water-insoluble alkali metal compounds in the alkali metal residues into water-soluble alkali metal constituents. The resultant aqueous solution containing water-soluble alkali metal constituents is then separated from the residue solids, which consist of the treated particles and any insoluble materials formed during the treatment step, and recycled to the gasification process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst. Preferably, the base that is added during the treatment step is an alkali metal hydroxide obtained by water washing the residue solids produced during the treatment step.

  2. Electrolysis

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Electrolysis is a well-established technology with many different applications. In particular, it can be used to produce hydrogen by using electricity to split water. As an increasing part of the energy system consists of fluctuating power sources such as wind and solar it becomes increasingly...

  3. Method of alkali solution concentration at electrochemical processing of eluates containing sodium salts

    OpenAIRE

    Трус, Інна Миколаївна; Гомеля, Микола Дмитрович; Радовенчик, Ярослав Вячеславович

    2013-01-01

    The paper gives the results of electrochemical concentration of alkali solutions, produced by electrolysis of sodium chloride or sodium sulfate. It was found that using two-chambered electrolyzer, the interelectrode space of which is separated by MK-40 membrane, allows increasing alkali concentration from 0.1-1.0D to 13D. It is shown that with anolyte alkalinity>0.1D alkali concentration in the anode region has little effect on electrolysis efficiency. Concentration is effective with alkal...

  4. Manufacturing of A micro probe using supersonic aided electrolysis process

    CERN Document Server

    Shyu, R F; Ho, Chi-Ting

    2008-01-01

    In this paper, a practical micromachining technology was applied for the fabrication of a micro probe using a complex nontraditional machining process. A series process was combined to machine tungsten carbide rods from original dimension. The original dimension of tungsten carbide rods was 3mm ; the rods were ground to a fixed-dimension of 50 micrometers using precision grinding machine in first step. And then, the rod could be machined to a middle-dimension of 20 micrometers by electrolysis. A final desired micro dimension can be achieved using supersonic aided electrolysis. High-aspect-ratio of micro tungsten carbide rod was easily obtained by this process. Surface roughness of the sample with supersonic aided agitation was compared with that with no agitation in electrolysis. The machined surface of the sample is very smooth due to ionized particles of anode could be removed by supersonic aided agitation during electrolysis. Deep micro holes can also be achieved by the machined high-aspect-rati tungsten c...

  5. STUDY ON TREATING ALKALI EXTRACTION -STAGE EFFLUENT FOR COLOR REMOVAL BY MICRO-ELECTROLYSIS METHOD

    Institute of Scientific and Technical Information of China (English)

    Xianying Xiao; Zhonghao Chen; Yuancai Chen

    2004-01-01

    The micro-electrolysis technology was applied in the decolorizing treatment of bleaching E-stage effluent and the influencing factors were discussed in this paper. The initial pH and the retention time were main factors influencing the color removal rate, in addition, adding air and enough pH for neutralization were necessary for the treatment. The test showed that the decolorizing result was efficient by micro-electrolysis treatment when adding air, initial pH was 3, 20 minutes of reaction time, the final pH10 for neutralization. The color removal rate was up to 90%. The chance of ultraviolet absorption spectrum also demonstrated the mechanism of color removal in the wastewater treatment.

  6. Alkali doped poly (2,5-benzimidazole) membrane for alkaline water electrolysis: Characterization and performance

    Science.gov (United States)

    Diaz, Liliana A.; Hnát, Jaromír; Heredia, Nayra; Bruno, Mariano M.; Viva, Federico A.; Paidar, Martin; Corti, Horacio R.; Bouzek, Karel; Abuin, Graciela C.

    2016-04-01

    The properties and performance of linear and cross-linked KOH doped ABPBI membranes as electrolyte/separator for zero gap alkaline water electrolysis cells are evaluated and compared with a commercial Zirfon® diaphragm. Stability in alkaline environment, swelling, thermal properties, water sorption, KOH uptake and conductivity of linear (L-ABPBI) and cross-linked (C-ABPBI) membranes doped with different concentrations of KOH are analyzed. Linear membranes show stability up to 3.0 mol·dm-3 KOH doping, while cross-linked membranes are stable up to 4.2 mol·dm-3 KOH doping. Both kinds of membranes exhibit good thermal stability and reasonable specific ionic conductivity at 22 °C in the range between 7 and 25 mS·cm-1, being slightly higher the conductivity of C-ABPBI membranes than that of L-ABPBI ones. In short-term electrolysis tests both L-ABPBI and C-ABPBI membranes show better performance than Zirfon diaphragm in the range from 50 to 70 °C. A current density of 335 mA·cm-2 at a cell voltage of 2.0 V is attained with C-ABPBI membranes doped in 3 mol·dm-3 KOH at 70 °C, a performance comparable with that of commercial units operating at temperatures ca. 80 °C and 30 wt% KOH (6.7 mol·dm-3) as electrolyte.

  7. Tritium and excess heat generation during electrolysis of aqueous solutions of alkali salts with nickel cathode

    International Nuclear Information System (INIS)

    A number of open cell electrolysis experiments of the Mills and Kneizys type using Nickel as cathode, Pt wire as anode and aqueous solutions of carbonates of Potassium, Sodium and Lithium (natural and enriched) as electrolyte have been carried out in three different laboratories at Trombay. The cells were fabricated out of commercial dewar vacuum flasks. The difference in temperature at equilibrium between the operating cells and that of an identical dummy reference flask was measured to deduce excess heat. The cells were calibrated using resistance heaters. In all, studies have been carried out so far in 29 electrolytic cells with various electrolytes. In some cases a mixture of H2O and D2O was used. The cells were operated for a few weeks at a time and excess heat up to a maximum of 70% appears to be present in most cells when the input joule power is upto a watt or two. The current density was less than 40 mA/cm2. Electrolyte samples before and after electrolysis were analysed for tritium content after microdistillation to eliminate chemiluminescence effects. Samples from 18 out of 29 experiments analysed have indicated tritium levels varying in the region of 46 Bq/ml to 3390 Bq/ml. One cell with enriched Li2CO3 solution in H2O which was monitored continuously for over a month indicated that tritium generation is continuous. Although the highest amount of tritium produced so far was with a K2CO3 in 25% D2O cell, the generation of tritium in cells containing only H2O is a new finding. (author)

  8. Energy-saving chlorine production. Chlor-alkali electrolysis using innovative cathode technology; Energiesparende Chlorpoduktion. Chlor-Alkali-Elektrolyse mit innovativer Kathoden-Technologie

    Energy Technology Data Exchange (ETDEWEB)

    Woltering, Peter; Hofmann, Philipp; Funck, Frank; Kiefer, Randolf; Baeumer, Ulf-Steffen; Donst, Dmitri; Schmitt, Carsten [Thyssen Krupp Uhde GmbH, Dortmund (Germany)

    2013-11-01

    Chlorine is used in the synthesis of almost two thirds of all chemical products. Producing chlorine from salt by electrolysis is a very energy-intensive process. Through their joint venture UHDENORA S.p.A., ThyssenKrupp Uhde and Industrie De Nora S.p.A. have played a major part in the development of a globally available technology that can produce chlorine using up to 30 percent less energy than conventional processes. It uses oxygen depolarized cathode technology with an innovative new cathode chamber design in an Uhde single-cell element. In Germany alone, converting all existing plants to the new technology would save enough electricity to power a city the size of Cologne. (orig.)

  9. Exergetic/energetic/economic analysis of three hydrogen production processes: electrolysis, hybrid, and thermochemical

    International Nuclear Information System (INIS)

    This paper presents the results of a combined first and second law analysis, along with capital and operating costs, for hydrogen production from water by means of electrolytic, hybrid, and thermochemical processes. The processes are SPE and Lurgi electrolysis with light water reactor power generation and sulfur cycle hybrid, thermochemical and SPE electrolysis with a very high temperature reactor primary energy source. 15 refs

  10. Study on the Inter-electrode Process of Aluminum Electrolysis

    Science.gov (United States)

    Yang, Youjian; Gao, Bingliang; Wang, Zhaowen; Shi, Zhongning; Hu, Xianwei

    2016-02-01

    The voltage distribution between carbon anode and aluminum cathode in cryolite electrolyte saturated with alumina was determined using a scanning reference electrode to investigate the inter-electrode process during aluminum electrolysis. The results showed that the anode-cathode-distance (ACD) is consisted of three parts: a relatively stable cathode boundary layer, bubble-free electrolyte layer, and gas-liquid layer near the anode. The aluminum diffusion layer with high electronic conductivity as well as the crystallization of cryolite was observed at the cathode boundary layer. The thickness of the aluminum diffusion layer varied with current density, which further determined the critical ACD. The thickness, coverage, and releasing frequency of the bubbles on both laboratory and industrial prebaked cells were derived, and it is found that the average bubble coverage decreases with current density, and the average coverage at 0.8 A cm-2 is approximately 50 pct.

  11. Process intensification: water electrolysis in a centrifugal acceleration field

    OpenAIRE

    Lao, Liyun; Ramshaw, C.; Yeung, Hoi

    2011-01-01

    Intensification of hydrogen production by carrying out water electrolysis in a centrifugal acceleration field has been demonstrated. A prototype single cell rotary water electrolyser was constructed, and a number of design challenges with regard to the practical application were addressed. The rotary electrolyser was tested over a range of current density, centrifugal acceleration, electrolyte concentration, temperature, and electrode geometry. The test results showed that a...

  12. Chapter 11. The energy supply of electrolytic series. The mechanization and automation of electrolysis process

    International Nuclear Information System (INIS)

    This chapter is devoted to energy supply of electrolytic series, mechanization and automation of electrolysis process. Thus, the energy supply of electrolytic series was considered. The mechanization of processes of electrolytic cells maintenance was considered as well. The automatic control system of technologic process was proposed.

  13. Study of hydride precipitation on zircaloy-4 by electrolysis process

    International Nuclear Information System (INIS)

    It had been conducted the hydration of zircaloy-4 by electrolysis in sulphuric acid electrolyte. In this experiment hydrogen in the from of atoms and ion is produced from electrolysis in a dilute sulphuric acid. The hydrogen is liberated in the vicinity of the cathode and the specimen itself was as the cathode. Electrolysis was performed at the current of 10 amperes and the potential of 30 volts. In this potential the affinity of zirconium increases and it is reactive enough to absorb hydrogen, which is close to the cathode. The absorbed hydrogen dissolves through the zircaloy-4. The hydrogenated specimens were heated at temperature 400 oC in inert atmosphere. Furthermore, the specimens were cooled in the furnace by the appropriate furnace cooling. The optical microscope was used for performing the metallographical analysis. The specimens were etched with solution of 25 ml 30% H2O2, 25 ml 70% HNO3 and 10 drops of 48% HF by swabbing technique for 10-20 seconds and washed by water. Based on ASTM 353 at 100x magnification the length of platelets is not less than 1.5 mm. From the microstructure image, hydride platelets have improperly been found, because part of them is in the particle from with diameter in the range of 1.4-7 micron meters which is uniformly distributed in the materials. The particle density is in the range of 13-36 particles per 3.5 mm2 of the material surface. The platelet orientation is not parallel to the rolling direction. This fact indicated that the basal plane of zircaloy-4 crystals is not paral let to the rolling direction

  14. THERMODYNAMIC CONSIDERATIONS FOR THERMAL WATER SPLITTING PROCESSES AND HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien

    2008-11-01

    A general thermodynamic analysis of hydrogen production based on thermal water splitting processes is presented. Results of the analysis show that the overall efficiency of any thermal water splitting process operating between two temperature limits is proportional to the Carnot efficiency. Implications of thermodynamic efficiency limits and the impacts of loss mechanisms and operating conditions are discussed as they pertain specifically to hydrogen production based on high-temperature electrolysis. Overall system performance predictions are also presented for high-temperature electrolysis plants powered by three different advanced nuclear reactor types, over their respective operating temperature ranges.

  15. Alkali and heavy metal emissions of the PCFB-process; Alkali- ja raskasmetallipaeaestoet PCFB-prosessista

    Energy Technology Data Exchange (ETDEWEB)

    Kuivalainen, R.; Eriksson, T.; Lehtonen, P. [Foster Wheeler Energia Oy, Karhula (Finland)

    1997-10-01

    Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula R and D Center since 1986. As part of the development, 10 MW PCFB test facility was built in 1989. The test facility has been used for performance testing with different coal types through the years 1990-1995 in order to gain data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The main object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measurements were performed using plasma assisted method of TUT Laboratory of Plasma Technology and wet absorption method of VTT Energy. The measurements were carried out during three test campaigns at PCFB Test Facility in Karhula. In autumn 1995 both VTT and TUT methods were used. The measurements of the following test period in spring 1996 were performed by VTT, and during the last test segment in autumn 1996 TUT method was in use. During the last test period, the TUT instrument was used as semi-continuous (3 values/minute) alkali analyzer for part of the time. The measured Na concentrations were below 30 ppb(w) in all measured data points. The results of K were below 10 ppb(w). The accuracies of the both methods are about +50 % at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions are at the same order of magnitude as the guideline emission limits estimated by gas turbine manufacturers

  16. Tritium-enrichment via CECE-process with high temperature steam electrolysis (HOT ELLY)

    International Nuclear Information System (INIS)

    Aqueous waste which is a by-product of nuclear fuel reprocessing plants, is contaminated with tritium in the form of HTO. This waste must be disposed of in a suitable compact manner. In order to minimize waste volume, tritiated water is enriched by several orders of magnitude of its original concentration. This task is accomplished by using the existing combined electrolysis catalytic exchange (CECE)-Process, which is presently in pilot operation with tritium in a German nuclear research facility (Kernforschungszentrum Karlsruhe, KfK, FRG). Substantial energy reduction can be achieved by substituting the conventional water electrolysis by high-temperature steam electrolysis (HOT ELLY) for separating tritiated water into its components

  17. Treatment of process water containing heavy metals with a two-stage electrolysis procedure in a membrane electrolysis cell

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R.; Krebs, P. [Technische Universitaet Dresden, Institut fuer Siedlungs- und Industriewasserwirtschaft, Mommsenstrasse 13, 01062 Dresden (Germany); Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany); Morgenstern, P. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Analytik, Permoserstrasse 15, D-04318 Leipzig (Germany); Foerster, H.J.; Thiele, W. [Eilenburger Elektrolyse- und Umwelttechnik GmbH, Ziegelstrasse 2, D-04838 Eilenburg (Germany)

    2005-04-01

    The capability of a two-stage electrochemical treatment for the regeneration of acidic heavy-metal containing process water was examined. The process water came from sediment bioleaching and was characterized by a wide spectrum of dissolved metals, a high sulfate content, and a pH of about 3. In the modular laboratory model cell used, the anode chamber and the cathode chamber were separated by a central chamber fitted with an ion exchanger membrane on either side. The experiments were carried out applying a platinum anode and a graphite cathode at a current density of 0.1 A/cm{sup 2}. The circulation flow of the process water in the batch process amounted to 35 L/h, the electrolysis duration was 5.5 h at maximum and the total electrolysis current was about 1 A. In the first stage, the acidic process water containing metals passed through the cathode chamber. In the second stage, the cathodically pretreated process water was electrolyzed anodically. In the cathode chamber the main load of dissolved Cu, Zn, Cr and Pb was eliminated. The sulfuric acid surplus of 3-4 g/L decreased to about 1 g/L, the pH rose from initially 3.0 to 4-5, but the desired pH of 9-10 was not achieved. Precipitation in the proximity to the cathode evidently takes place at a higher pH than farther away. The dominant process in the anode chamber was the precipitation of amorphous MnO{sub 2} owing to the oxidation of dissolved Mn(II). The further depletion of the remaining heavy metals in the cathodically pretreated process water by subsequent anodic treatment was nearly exhaustive, more than 99 % of Cd, Cr, Cu, Mn, Ni, Pb, and Zn were removed from the leachate. The high depletion of heavy metals might be due to both the sorption on MnO{sub 2} precipitates and/or basic ferrous sulfate formed anodically, and the migration of metal ions through the cation exchanger membrane via the middle chamber into the cathode chamber. In the anode chamber, the sulfuric acid content increased to 6-7 g/L and the

  18. Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process.

    Science.gov (United States)

    Cao, X Z; Li, Y M

    2011-01-01

    Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment. PMID:22053469

  19. Tritium-enrichment via CECE-process with high-temperature steam electrolysis (HOT ELLY)

    International Nuclear Information System (INIS)

    Reprocessing of nuclear fuel elements produces tritiated water which has to be disposed of for final storage. The amount of waste can be significantly reduced by tritium-enrichment. Besides distillation the CECE-process (Combined Electrolysis Catalytic Exchange) can be applied to that. The objective of the study was the investigation of questions concerning process engineering and safety aspects related to high-temperature steam electrolysis ('HOT ELLY') with respect to the potential for its application within the radioactive system of the CECE-process instead of a conventional electrolyzer. A process engineering concept for the integration of a high temperature electrolyzer into the CECE-process was designed. A comparative assessment with respect to the application of a conventional electrolysis-process revealed the usage of a high temperature electrolyzer to be attractive. Main advantages are significant reduction of the radioactive inventory and the avoiding of secondary waste. Prohibitive safety problems are not seen. (orig.) With 39 refs., 18 tabs., 38 figs

  20. Al/sub 2/S/sub 3/ preparation and use in electrolysis process for aluminum production

    Science.gov (United States)

    Hsu, C.C.; Loutfy, R.O.; Yao, N.P.

    A continuous process for producing aluminum sulfide and for electrolyzing the aluminum sulfide to form metallic aluminum in which the aluminum sulfide is produced from aluminum oxide and COS or CS/sub 2/ in the presence of a chloride melt which also serves as the electrolysis bath. Circulation between the reactor and electrolysis cell is carried out to maintain the desired concentration of aluminum sulfide in the bath.

  1. Application of the Maxwell–Stefan theory to the membrane electrolysis process. Model development and simulations

    OpenAIRE

    Hogendoorn, J. A.; Van der Veen, A.J.; Stegen, J.H.G. van der; Kuipers, J.A.M.; Versteeg, G. F.

    2001-01-01

    A model is developed which describes the mass transfer in ion-selective membranes as used in the chloralkali electrolysis process. The mass transfer model is based on the Maxwell–Stefan theory, in which the membrane charged groups are considered as one of the components in the aqueous mixture. The Maxwell–Stefan equations are re-written in such a way that the current density can be used as an input parameter in the model, which circumvents an extensive numerical iterative process in the numer...

  2. TECHNICAL NOTE: Manufacturing of a micro-tungsten carbide electrode using a supersonic-aided electrolysis process

    Science.gov (United States)

    Weng, Feng-Tsai; Ho, Chi-Ting

    2008-03-01

    In this study, a novel micromachining technology for fabricating micro parts was described. The original diameter of a tungsten carbide rod was 3 mm, and it was first processed to a rod with a diameter of 50 µm by a precision-grinding process. It could then be machined to the desired diameter by a supersonic-aided electrolysis process. A high-aspect ratio of the micro-tungsten carbide rod was easily obtained by this process. The surface roughness of the sample that was processed by electrolysis with supersonic-aided agitation was compared with that of the sample obtained without agitation. The machined surface of the sample was smooth, and the reason may be that ionized particles in the anode could be removed by supersonic-aided agitation during the electrolysis process. A microelectrode with a tip of approximately 1 µm could be obtained by this process.

  3. An exergetic/energetic/economic analysis of three hydrogen production processes - Electrolysis, hybrid, and thermochemical

    Science.gov (United States)

    Funk, J. E.; Eisermann, W.

    This paper presents the results of a combined first and second law analysis, along with capital and operating costs, for hydrogen production from water by means of electrolytic, hybrid, and thermochemical processes. The processes are SPE and Lurgi electrolysis with light water reactor power generation and sulfur cycle hybrid, thermochemical and SPE electrolysis with a very high temperature reactor primary energy source. Energy and Exergy (2nd law) flow diagrams for the process are shown along with the location and magnitude of the process irreversibilities. The overall process thermal (1st law) efficiencies vary from 25 to 51% and the exergetic (2nd law) efficiencies, referred to the fuel for the primary energy source, vary from 22 to 45%. Capital and operating costs, escalated to 1979 dollars, are shown for each process for both the primary energy source and the hydrogen production plant. All costs were taken from information available in the open literature and are for a plant capacity of 100 x 10 to the 6th SCF/day. Production costs vary from 10 to 18 $/GJ, based on the higher heating value of hydrogen, and are based on a 90% plant operating factor with a 21% annual charge on total capital costs.

  4. Macrokinetic relationships between anodic processes in chlorine electrolysis on ruthenium-titanium oxide anodes

    International Nuclear Information System (INIS)

    Effect of porosity on kinetics of the main (chlorine evolution) and side (oxygen evolution and anodic dissolution of ruthenium dioxide) reactions for chlorine electrolysis conditions has been analyzed. Making allowance for chlorine hydrolysis secondary reaction, the distribution of chlorine concentration, solution pH and current densities of the main and side processes over the porous anode depth, have been found. It is shown that solution acidification in the anode pores due to chlorine hydrolysis can bring about replacement of oxygen evolution and ruthenium dioxide dissolution side reactions toward the porous anode external sides thus affecting its selectivity and corrosion resistance

  5. An Environmentally Friendly Process Involving Refining and Membrane-Based Electrolysis for Magnesium Recovery from Partially Oxidized Scrap Alloy

    Science.gov (United States)

    Guan, Xiaofei; Pal, Uday B.; Powell, Adam C.

    2013-10-01

    Magnesium is recovered from partially oxidized scrap alloy by combining refining and solid oxide membrane (SOM) electrolysis. In this combined process, a molten salt eutectic flux (45 wt.% MgF2-55 wt.% CaF2) containing 10 wt.% MgO and 2 wt.% YF3 was used as the medium for magnesium recovery. During refining, magnesium and its oxide are dissolved from the scrap into the molten flux. Forming gas is bubbled through the flux and the dissolved magnesium is removed via the gas phase and condensed in a separate condenser at a lower temperature. The molten flux has a finite solubility for magnesium and acts as a selective medium for magnesium dissolution, but not aluminum or iron, and therefore the magnesium recovered has high purity. After refining, SOM electrolysis is performed in the same reactor to enable electrolysis of the dissolved magnesium oxide in the molten flux producing magnesium at the cathode and oxygen at the SOM anode. During SOM electrolysis, it is necessary to decrease the concentration of the dissolved magnesium in the flux to improve the faradaic current efficiency and prevent degradation of the SOM. Thus, for both refining and SOM electrolysis, it is very important to measure and control the magnesium solubility in the molten flux. High magnesium solubility facilitates refining whereas lower solubility benefits the SOM electrolysis process. Computational fluid dynamics modeling was employed to simulate the flow behavior of the flux stirred by the forming gas. Based on the modeling results, an optimized design of the stirring tubes and its placement in the flux are determined for efficiently removing the dissolved magnesium and also increasing the efficiency of the SOM electrolysis process.

  6. Study on electrodeposition of La-Mg alloys in chloride system with molten salt electrolysis process

    International Nuclear Information System (INIS)

    This work presents the study on electrochemical codeposition of La-Mg alloys on molybdenum electrode in LaCl3-MgCl2-LiCl-KCl melt. The feasibility of alloy deposition was studied extensively by implementing electro analytical techniques like cyclic voltametry, square wave voltametry and chronopotentiometry in a temperature range of 923 to 1023K. The mechanism of codeposition was also studied implementing the above mentioned transient electrochemical techniques. The components of the alloy element can be controlled by fixing the concentration of feeding salt in the electrolyte. Based on this basic investigation, deposition of La-Mg alloys were attempted on molybdenum electrode at higher operating temperature above 1073K to obtain the product in liquid state to have better purity. The material has been prepared in 200-300g scale to support practical application. Different phases of La-Mg alloys could be prepared by galvanostatic electrolysis by varying the concentration of LaCl3 and MgCl2 in the feed material. X-ray diffraction (XRD) and Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) techniques were implemented to characterize the phase and microstructure of the alloys respectively. Inductively couple plasma-atomic emission spectroscopy (ICP-AES) analyses of the obtained products by electrolysis showed that chemical compositions of La-Mg alloys were consistent with XRD results. The effects of various process parameters such as concentration of magnesium chloride in bath, temperature of electrolysis and cathode current density on current efficiency have been investigated. These parameters were standardized to get highest current efficiency and yield in preparing La-Mg alloys in 200-300 g scale in our lab set-up. (author)

  7. Titanium metal obtention by fused salts electrolysis

    International Nuclear Information System (INIS)

    Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

  8. Advances in the electrolysis of tritiated water for its application to a fusion plasma processing plant

    International Nuclear Information System (INIS)

    The exhaust plasma processing scheme, proposed a few years ago as an alternative to the TSTA plant in operation at Los Alamos (N.M.), USA, required further research on some topics such as a low liquid inventory electrolytic cell and the types of separator or membrane resistant to beta radiation. Moreover, it was suggested that the value of the separation factors among H2, D2, T2 should be checked during the electrolysis by using different cathode materials in an alkaline medium. The results of the experimental work carried out on these topics have shown the feasibility of the process although some improvements are still possible as far as the optimization of the separators and the design of the electrolytic cells are concerned. This paper describes the research carried out in the JRC Ispra (Italy) together with some Institutes which have studied contracts with our Establishment

  9. A new mechanism for radiation damage processes in alkali halides

    NARCIS (Netherlands)

    Dubinko, V.I.; Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    1999-01-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution o

  10. On process model representation and AlF{sub 3} dynamics of aluminium electrolysis cells

    Energy Technology Data Exchange (ETDEWEB)

    Drengstig, Tormod

    1997-12-31

    This thesis develops a formal graphical based process representation scheme for modelling complex, non-standard unit processes. The scheme is based on topological and phenomenological decompositions. The topological decomposition is the modularization of processes into modules representing volumes and boundaries, whereas the phenomenological decomposition focuses on physical phenomena and characteristics inside these topological modules. This defines legal and illegal connections between components at all levels and facilitates a full implementation of the methodology into a computer aided modelling tool that can interpret graphical symbols and guide modelers towards a consistent mathematical model of the process. The thesis also presents new results on the excess AlF{sub 3} and bath temperature dynamics of an aluminium electrolysis cell. A dynamic model of such a cell is developed and validated against known behaviour and real process data. There are dynamics that the model does not capture and this is further discussed. It is hypothesized that long-term prediction of bath temperature and excess AlF{sub 3} is impossible with a current efficiency model considering only bath composition and temperature. A control strategy for excess AlF{sub 3} and bath temperature is proposed based on an almost constant AlF{sub 3} input close to average consumption and energy manipulations to compensate for the disturbances. 96 refs., 135 figs., 22 tabs.

  11. Engineering Process Model for High-Temperature Electrolysis System Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Carl M. Stoots; James E. O& #39; Brien; Michael G. McKellar; Grant L. Hawkes

    2005-11-01

    In order to evaluate the potential hydrogen production performance of large-scale High-Temperature Electrolysis (HTE) operations, we have developed an engineering process model at INL using the commercial systems-analysis code HYSYS. Using this code, a detailed process flowsheet has been defined that includes all of the components that would be present in an actual plant such as pumps, compressors, heat exchangers, turbines, and the electrolyzer. Since the electrolyzer is not a standard HYSYS component, a custom one-dimensional electrolyzer model was developed for incorporation into the overall HYSYS process flowsheet. This electrolyzer model allows for the determination of the operating voltage, gas outlet temperatures, and electrolyzer efficiency for any specified inlet gas flow rates, current density, cell active area, and external heat loss or gain. The one-dimensional electrolyzer model was validated by comparison with results obtained from a fully 3-D computational fluid dynamics model developed using FLUENT. This report provides details on the one-dimensional electrolyzer model, the HYSYS process model for a 300 MW HTE plant, and some representative results of parametric studies performed using the HYSYS process model.

  12. A new mechanism for radiation damage processes in alkali halides

    OpenAIRE

    Dubinko, V. I.; Turkin, A.A.; Vainshtein, D.I.; Hartog, H.W. den

    1999-01-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution of all experimentally observed extended defects: metal colloids, gas bubbles, and vacancy voids. Voids are shown to arise and grow large due to the reaction between F and VF centers at the surface o...

  13. A new mechanism for radiation damage processes in alkali halides

    Science.gov (United States)

    Dubinko, V. I.; Turkin, A. A.; Vainshtein, D. I.; den Hartog, H. W.

    1999-12-01

    We present a theory of radiation damage formation in alkali halides based on a new mechanism of dislocation climb, which involves the production of VF centers (self-trapped hole neighboring a cation vacancy) as a result of the absorption of H centers of dislocation lines. We consider the evolution of all experimentally observed extended defects: metal colloids, gas bubbles, and vacancy voids. Voids are shown to arise and grow large due to the reaction between F and VF centers at the surface of halogen bubbles. Voids can ignite a back reaction between the radiolytic products resulting in decomposition of the irradiated material.

  14. Application of the Maxwell-Stefan theory to the transport in ion-selective membranes used in the chloralkali electrolysis process

    OpenAIRE

    Stegen, J.H.G. van der; Van der Veen, A.J.; Weerdenburg, H.; Hogendoorn, J. A.; Versteeg, G. F.

    1999-01-01

    The results of a fundamental mass transport model based on the Maxwell-Stefan approach are compared to experimental data obtained by Akzo-Nobel for a Dupont Nafion ion-selective membrane as used in chloralkali electrolysis processes. The main problem in the application of the Maxwell Stefan based mass transfer model to the chloralkali electrolysis process is a lack of available diffusivities for the membrane. Estimation of these diffusivities in the membrane based on an earlier presented meth...

  15. Plasma assisted measurements of alkali metal concentrations in pressurized combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland). Dept. of Physics

    1996-12-01

    The plasma assisted method for continuous measurement of alkali concentrations in product gas flows of pressurized energy processes will be tested and applied at the 1.6 MW PFBC/G facility at Delft University of Technology in the Netherlands. During the reporting period the alkali measuring device has been tested under pressurized conditions at VTT Energy, DMT, Foster-Wheeler Energia and ABB Carbon. Measurements in Delft will be performed during 1996 after installation of the hot gas filter. The original plan for measurements in Delft has been postponed due to schedule delays in Delft. The results are expected to give information about the influence of different process conditions on the generation of alkali vapours, the comparison of different methods for alkali measurement and the specific performance of our system. This will be the first test of the plasma assisted measurement method in a gasification process. The project belongs to the Joule II extension program under contract JOU2-CT93-0431. (author)

  16. The influence of different parameters on the hydration process of binders based on alkali activated slag

    Directory of Open Access Journals (Sweden)

    DARKO KRIZAN

    2005-02-01

    Full Text Available The influence of certain types of activators (water glass Na2O·nSiO2 and sodium-metasilicate Na2SiO3·5H2O on the hydration process of alkali activated slag was investigated in this study. The influence of activator concentration, specific surface area of the slag and the modulus n of the water glass (mass ratio between SiO2 and Na2O on the kinetics of the hydration process i.e., the change of compressive strength were also investigated. Poorly crystallized low base calcium silicate hydrate C–S–H (I is the main hydration product of alkali activated slag regardless of the activator used. This is the reason for the rapid increase in the strength of alkali activated slag and also of the very high strength values. The strength growth rate and strength values were significantly higher when sodium–metasilicate was used as the activator than when water glass was used. The specific surface area of the slag and the activator concentration are parameters which have a closely connected influence on strength and their action is cumulative. The modulus n of water glass does not have an explicit influence on the strength of alkali activated slag.

  17. Effects of a Pre-Filter and Electrolysis Systems on the Reuse of Brine in the Chinese Cabbage Salting Process

    OpenAIRE

    Kim, Dong-Ho; Yoo, Jae Yeol; Jang, Keum-Il

    2016-01-01

    In this study, the effects of a pre-filter system and electrolysis system on the safe and efficient reuse of brine in the cabbage salting process were investigated. First, sediment filter-electrolyzed brine (SF-EB) was selected as brine for reuse. Then, we evaluated the quality and microbiological properties of SF-EB and Chinese cabbage salted with SF-EB. The salinity (9.4%) and pH (4.63) of SF-EB were similar to those of control brine (CB). SF-EB turbidity was decreased (from 0.112 to 0.062)...

  18. Alkali and heavy metal emissions of the PCFB-process; Alkalipaeaestoet PCFB-prosessissa

    Energy Technology Data Exchange (ETDEWEB)

    Kuivalainen, R.; Eriksson, T.; Lehtonen, P. [Foster Wheeler Energia Oy, Karhula (Finland)

    1996-12-01

    Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula R and D Center since 1986. As a part of the development, 10 MW PCFB Test Facility was built in 1989. The Test Facility has been used for performance testing with different coal types through the years 1990-1995 in order to gain data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The project Y44 `Alkali and heavy metal emissions of the PCFB-process` was part of national LIEKKI 2 research program. The main object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measurements were performed using plasma assisted method by TUT Laboratory of Plasma Technology and wet absorption method of VTT Energy. The measured Na concentrations were below 30 ppb(w) in all measured data points. The results of K were below 10 ppb(w). The accuracies of the both methods are about + 50 % at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions are at the same order of magnitude as the guideline emission limits estimated by gas turbine manufacturers. The measurements and development of the analyses methods are planned to be continued during PCFB test runs in spring 1996 for example within Joule II research program. (author)

  19. H2-MHR conceptual designs based on the sulphur-iodine process and high-temperature electrolysis

    International Nuclear Information System (INIS)

    For electricity and hydrogen production, the advanced reactor technology receiving the most international interest is a modular, passively safe version of the high-temperature, helium-cooled reactor referred to in the USA as the Modular Helium Reactor (MHR). Because of its ability to produce high-temperature helium, the MHR is well suited for a number of process-heat applications, including hydrogen production. Two hydrogen-production technologies have emerged as leading candidates for coupling to the MHR: (1) thermochemical water splitting using the Sulphur-Iodine (SI) process and (2) High-Temperature Electrolysis (HTE). In this paper, we provide an update on conceptual designs being developed for coupling the MHR to the SI process and HTE. These concepts are referred to as the SI-based H2-MHR and the HTE-based H2-MHR, respectively. (author)

  20. Electrochemical deposition of La-Mg alloys in LaCl3-MgCl2-KCl system with molten salt electrolysis process

    Directory of Open Access Journals (Sweden)

    Sahoo Kumar D.

    2014-01-01

    Full Text Available La-Mg alloys of different compositions were prepared by electrolysis of LaCl3-MgCl2-KCl melts. Different phases of La-Mg alloys were characterized by X-ray diffraction (XRD and Scanning Electron Microscopy (SEM. Energy dispersive spectrometry (EDS and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES analyses showed that chemical compositions of La-Mg alloys were consistent with phase structures of XRD pattern, and magnesium content in the alloy could be controlled by electrolysis parameters. The effects of various process parameters such as concentration of magnesium chloride in the bath, temperature of electrolysis and cathode current density on the current efficiency have been investigated. A maximum current efficiency of 85% and yield of 80% was obtained from the bath at 12.5A/cm2 current density at an operating temp 850°C.

  1. Magnetic Resonance Imaging of Electrolysis.

    Science.gov (United States)

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  2. Optimization of electrocatalytic properties of NiMoCo foam electrode for water electrolysis by post-treatment processing

    Institute of Scientific and Technical Information of China (English)

    Jian-Wei Wang; Yue-Fa Wang; Jing-Guo Zhang; Yan-Lin Yu; Ge-Ge Zhou; Lei Cheng; Lin-Shan Wang

    2015-01-01

    Hydrogen is a potential alternative to fossil fuels in coping with the increased global energy demand,and water electrolysis is an attractive approach for H2 production.Nickel-molybdenum-cobalt (NiMoCo) foam electrodes used for water electrolysis were prepared by the electrodeposition method,and the influence of heat treatments on the surface structure of NiMoCo foam electrodes,mechanical properties,and electrochemical performance of the synthesized electrodes was investigated in order to optimize the post-treatment processes.The residual carbon in the surface of the electrode was removed by decarbonization in the atmospheric condition.The carbon content decreases to lower than 200 × 10-6 when the temperature exceeds 500 ℃.Next,the material is reduced in hydrogen atmosphere from 500 to 1100 ℃ to remove the surface oxides.As the temperature increases,the surface molybdenum content increases significantly between 500 and 800 ℃,the surface grains become coarser,and the tensile strength and elongation increase as well.The lowest polarization overpotential is obtained at 800 ℃.Below 800 ℃,the electrode is only partially reduced and some black oxide zones are observed on the electrode surface,which leads to the higher polarization overpotential.The samples heat-treated at the temperatures of higher than 800 ℃ show better strength and toughness as well as brighter appearance.However,the surface particle coarsening leads to a decrease in the specific surface area and a higher overpotential.

  3. Optimizing the Dyeing Process of Alkali-Treated Polyester Fabric with Dolu Natural Dye

    Directory of Open Access Journals (Sweden)

    M.F. Shahin

    2014-06-01

    Full Text Available An attempt has been made to optimize the process of dyeing polyester (PET fabric with natural dyes. Polyester has been first treated with NaOH solution in order to study its impact on the dyeability to the natural dye. The required and used colour component was extracted from a natural plant, namely: Rhubarb; Rheum officinale. The chemical structure of the used colouring matter is observed to have all the characteristics of a typical disperse dye. The colour strength of PET fabric was noticed to increase as a result of alkali treatment which may be attributed to the alteration in the hydrophobicity of polyester fibre. The most effective parameters that may affect the dye uptake of the natural dye on alkali-treated PET fabric and the final dyeing properties including dye bath pH, dyeing temperature and time were studied in details. The behaviour of the selected and used natural dye was found to be similar to that of disperse dyes. Addition of salicylic acid to the dye bath accelerated the rate of dyeing and subsequently higher colour strength was attained. Non- ionic dispersing agent was also used to ensure better dyeing uniformity and higher dispersion stability of dye liquor.

  4. Alkali-aided enzymatic viscosity reduction of sugar beet mash for novel bioethanol production process

    Energy Technology Data Exchange (ETDEWEB)

    Srichuwong, Sathaporn; Arakane, Mitsuhiro; Fujiwara, Maki; Zhang, Zilian; Tokuyasu, Ken [National Food Research Institute, National Agriculture and Food Research Organization (NARO), 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642 (Japan); Takahashi, Hiroyuki [National Agricultural Research Center for Hokkaido Region, NARO, Shinsei, Memuro, Hokkaido 082-0081 (Japan)

    2010-09-15

    Ethanol fermentation of fresh sugar beet mash (SBM) could give a benefit on reducing energy input for sugar diffusion, juice separation, and water evaporation as used in conventional practices, thus offering promise as a low energy process. Actions of cell-wall degrading enzymes provide a mash with low viscosity, which can be easily fermented to ethanol. However, a several-fold higher enzyme loading was required for viscosity reduction of SBM compared with that of potato mash. In this study, the use of dilute alkali treatment (0.025-0.15 N NaOH, 25 C, 1 h) in enhancing enzymatic viscosity reduction of SBM was evaluated. The results showed that higher NaOH concentration enhanced demethylation and deacetylation of SBM, resulting in greater performances of the enzymes on reducing viscosity. Efficient enzymatic viscosity reduction of SBM was observed with the 0.1 N NaOH treatment. On the other hand, untreated SBM was highly resistant to viscosity reduction, even though a 20-fold more enzyme loading was used. The resulting mash containing 12-13% (w/v) sucrose yielded 7-8% (v/v) ethanol after 24 h of fermentation (90% efficiency). Accordingly, alkali treatment can be applied for facilitating the use of fresh sugar beet for ethanol production. (author)

  5. Alkali-aided enzymatic viscosity reduction of sugar beet mash for novel bioethanol production process

    International Nuclear Information System (INIS)

    Ethanol fermentation of fresh sugar beet mash (SBM) could give a benefit on reducing energy input for sugar diffusion, juice separation, and water evaporation as used in conventional practices, thus offering promise as a low energy process. Actions of cell-wall degrading enzymes provide a mash with low viscosity, which can be easily fermented to ethanol. However, a several-fold higher enzyme loading was required for viscosity reduction of SBM compared with that of potato mash. In this study, the use of dilute alkali treatment (0.025-0.15 N NaOH, 25 oC, 1 h) in enhancing enzymatic viscosity reduction of SBM was evaluated. The results showed that higher NaOH concentration enhanced demethylation and deacetylation of SBM, resulting in greater performances of the enzymes on reducing viscosity. Efficient enzymatic viscosity reduction of SBM was observed with the 0.1 N NaOH treatment. On the other hand, untreated SBM was highly resistant to viscosity reduction, even though a 20-fold more enzyme loading was used. The resulting mash containing 12-13% (w/v) sucrose yielded 7-8% (v/v) ethanol after 24 h of fermentation (90% efficiency). Accordingly, alkali treatment can be applied for facilitating the use of fresh sugar beet for ethanol production.

  6. Nano Si preparation by constant cell voltage electrolysis of FFC-Cambridge Process in molten CaCl2

    Institute of Scientific and Technical Information of China (English)

    Ji; Zhao; Shengmei; Lu; Linyan; Hu; Can; Li

    2013-01-01

    Using FFC-Cambridge Process to prepare Si from SiO2 is a promising method to prepare nanostructured and highly pure silicon for solar cells.However,the method still has many problems unsolved and the controlling effect of the cell voltage on silicon product is not clear.Here we report in this article that nano cluster-like silicon product with purity of 99.95%has been prepared by complete conversion of raw material SiO2,quartz glass plate,using constant cell voltage electrolysis FFC-Cambridge Process.By analysis of XRD,EDS,TEM,HRTEM and ICP-AES as well as the discussion from the thermodynamics calculation,the morphology and components of the product based on the change of cell voltage are clarified.It is clear that pure silicon could be prepared at the cell voltage of 1.7 2.1 V in this reaction system.The silicon material have cluster-like structure which are made of silicon nanoparticles in 20 100 nm size.Interestingly,the cluster-like nano structure of the silicon can be tuned by the used cell voltage.The purity,yield and the energy cost of silicon product prepared at the optimized cell voltage are discussed.The purity of the silicon product could be further improved,hence this method is promising for the preparation of solar grade silicon in future.

  7. Characteristics and formation of [AlO4Al12(OH)24(H2O)12]7+ in electrolysis process

    Institute of Scientific and Technical Information of China (English)

    刘会娟; 曲久辉; 张素娟; 胡承志

    2002-01-01

    [AlO4Al12(OH)24(H2O)12]7+(Al13) formation in electrolysis process is studied. The results detected by 27Al NMR spectroscopy show that high content of Al13 polymer is formed in the partially hydrolyzed aluminum solution prepared by controlled electrolysis process. In the produced electrolyte of total Al concentration (Al) 2.0 mol* L-1 with a basicity (B = OH/Al molar ratios) of 2.0, the content of Al13 polymer is over 60% of total Al. Dynamic light scattering shows that the size distribution of the final electrolyte solutions ( = 2.0 mol*L-1) is trimodal with B = 2.0 and bimodal with B = 2.5. The aggregates of Al13 complexes increase the particle size of partially hydrolyzed aluminum solution.

  8. Purification of Organic Wastewater Containing Cu2+ and Cr3+ by a Combined Process of Micro Electrolysis and Biofilm

    Institute of Scientific and Technical Information of China (English)

    李天成; 姜斌; 冯霞; 王大为; 袁绍军; 李鑫钢

    2003-01-01

    A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastew-aters containing heavy metal ions such as Cu2+ and Cr3+,and the relevant purifying mechanism was also addressed. In detail,organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes,However,for heavy metal ions (Cu2+,Cr3+),part was removed by electrodeposition,and some was adorbed on biofilm.In order to compare with the combined process of micro electrolysis and biofilm,the experimental data of micro electrolysis process (intermittent )or biofilm process (continuous)were provided,and the kinetic data of C6H12O6(glucose)biodegradation by cultured microbes or acclimated microbes were also obtained,These experimental results indicated that for wastewater initially consisted of C6H12O6(500 mg.L-1),Cu2+ and Cr3+(10mg.L6-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the leve of 55-65 mg.L-1),after treatment,its concentrations of C6H12O6,Cu2+ and Cr3+ were lowered to the level of 55-65 mg.L-1,and less than 1mg.L-1,respectively,And the industrial reused water standards could be met by treated wastewater.

  9. Integrated hydrogen production process from cellulose by combining dark fermentation, microbial fuel cells, and a microbial electrolysis cell

    KAUST Repository

    Wang, Aijie

    2011-03-01

    Hydrogen gas production from cellulose was investigated using an integrated hydrogen production process consisting of a dark fermentation reactor and microbial fuel cells (MFCs) as power sources for a microbial electrolysis cell (MEC). Two MFCs (each 25mL) connected in series to an MEC (72mL) produced a maximum of 0.43V using fermentation effluent as a feed, achieving a hydrogen production rate from the MEC of 0.48m 3 H 2/m 3/d (based on the MEC volume), and a yield of 33.2mmol H 2/g COD removed in the MEC. The overall hydrogen production for the integrated system (fermentation, MFC and MEC) was increased by 41% compared with fermentation alone to 14.3mmol H 2/g cellulose, with a total hydrogen production rate of 0.24m 3 H 2/m 3/d and an overall energy recovery efficiency of 23% (based on cellulose removed) without the need for any external electrical energy input. © 2010 Elsevier Ltd.

  10. Effects of a Pre-Filter and Electrolysis Systems on the Reuse of Brine in the Chinese Cabbage Salting Process.

    Science.gov (United States)

    Kim, Dong-Ho; Yoo, Jae Yeol; Jang, Keum-Il

    2016-06-01

    In this study, the effects of a pre-filter system and electrolysis system on the safe and efficient reuse of brine in the cabbage salting process were investigated. First, sediment filter-electrolyzed brine (SF-EB) was selected as brine for reuse. Then, we evaluated the quality and microbiological properties of SF-EB and Chinese cabbage salted with SF-EB. The salinity (9.4%) and pH (4.63) of SF-EB were similar to those of control brine (CB). SF-EB turbidity was decreased (from 0.112 to 0.062) and SF-EB residual chlorine (15.86 ppm) was higher than CB residual chlorine (0.31 ppm), and bacteria were not detected. Salinity (2.0%), pH (6.21), residual chlorine (0.39 ppm), chromaticity, hardness, and chewiness of cabbage salted with SF-EB were similar to those of cabbage salted with CB. The total bacterial count in cabbage salted with CB was increased as the number of reuses increased (from 6.55 to 8.30 log CFU/g), whereas bacteria in cabbage salted with SF-EB was decreased (from 6.55 to 5.21 log CFU/g). These results show that SF-EB improved the reusability of brine by removing contaminated materials and by sterilization. PMID:27390732

  11. Investigation of Electrolysis Process Performance by Graphite Electrodes for De-Colorization of Phenolphthalein and Phenol Red from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Mohamadreza Massoudinejad

    2015-11-01

    Full Text Available This study elucidates the de-colorization of phenolphthalein and phenol red from aqueous solution through electrochemical oxidation technique. An electrochemical reactor had 1 liter volume that used 2 graphite electrodes. Effect of electric power voltage, inter electrode distance and electrolyte concentration was investigated in this system. It was found that the optimum conditions for completely removal of phenolphthalein was at voltage of 48 V, retention time of 9 minutes, distance between the electrode of 5 cm, and the salt concentration of 1.5 g/l. Also completely removal of phenol red was at voltage of 48 V, retention time of 8 minutes, distance between the electrode of 5 cm, and the salt concentration of 2 g/l. Phenol red and phenolphthalein COD removal efficiency was 85 and 80 percent respectively. The results suggest that the electrolysis process is an effective way to removal of phenolphthalein and phenol red color from effluent, because of it can completely remove the color in a short time.

  12. Effects of a Pre-Filter and Electrolysis Systems on the Reuse of Brine in the Chinese Cabbage Salting Process

    Science.gov (United States)

    Kim, Dong-Ho; Yoo, Jae Yeol; Jang, Keum-Il

    2016-01-01

    In this study, the effects of a pre-filter system and electrolysis system on the safe and efficient reuse of brine in the cabbage salting process were investigated. First, sediment filter-electrolyzed brine (SF-EB) was selected as brine for reuse. Then, we evaluated the quality and microbiological properties of SF-EB and Chinese cabbage salted with SF-EB. The salinity (9.4%) and pH (4.63) of SF-EB were similar to those of control brine (CB). SF-EB turbidity was decreased (from 0.112 to 0.062) and SF-EB residual chlorine (15.86 ppm) was higher than CB residual chlorine (0.31 ppm), and bacteria were not detected. Salinity (2.0%), pH (6.21), residual chlorine (0.39 ppm), chromaticity, hardness, and chewiness of cabbage salted with SF-EB were similar to those of cabbage salted with CB. The total bacterial count in cabbage salted with CB was increased as the number of reuses increased (from 6.55 to 8.30 log CFU/g), whereas bacteria in cabbage salted with SF-EB was decreased (from 6.55 to 5.21 log CFU/g). These results show that SF-EB improved the reusability of brine by removing contaminated materials and by sterilization. PMID:27390732

  13. The Technological Improvements of Aluminum Alloy Coloring by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    LI Nai-jun

    2004-01-01

    The technological process of coloring golden-tawny on aluminum alloy by electrolysis was improved in this paper. The optimum composition of electrolyte was found, the conditions of deposition and anodic oxidation by electrolysis were studied. The oxidative membrane on aluminum alloy was satisfying, the colored aluminum alloy by electrolysis is uniformity,bright and beautiful, and the coloring by electrolysis is convenient and no pollution.

  14. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...

  15. PROCESS MODEL FOR THE PRODUCTION OF SYNGAS VIA HIGH TEMPERATURE CO-ELECTROLYSIS

    International Nuclear Information System (INIS)

    A process model has been developed to evaluate the potential performance of a large-scale high-temperature coelectrolysis plant for the production of syngas from steam and carbon dioxide. The coelectrolysis process allows for direct electrochemical reduction of the steam-carbon dioxide gas mixture, yielding hydrogen and carbon monoxide, or syngas. The process model has been developed using the HYSYS systems analysis code. Using this code, a detailed process flowsheet has been defined that includes all the components that would be present in an actual plant such as pumps, compressors, heat exchangers, turbines, and the electrolyzer. Since the electrolyzer is not a standard HYSYS component, a custom one-dimensional coelectrolysis model was developed for incorporation into the overall HYSYS process flowsheet. The 1-D coelectrolysis model assumes local chemical equilibrium among the four process-gas species via the shift reaction. The electrolyzer model allows for the determination of coelectrolysis outlet temperature, composition (anode and cathode sides), mean Nernst potential, operating voltage and electrolyzer power based on specified inlet gas flow rates, heat loss or gain, current density, and cell area-specific resistance. The one-dimensional electrolyzer model was validated by comparison with results obtained from a fully 3-D computational fluid dynamics model developed using FLUENT, and by comparison to experimental data. This paper provides representative results obtained from the HYSYS flowsheet model for a 300 MW coelectrolysis plant, coupled to a high-temperature gas-cooled nuclear reactor. The coelectrolysis process, coupled to a nuclear reactor, provides a means of recycling carbon dioxide back into a useful liquid fuel. If the carbon dioxide source is based on biomass, the entire process would be climate neutral

  16. Optimizing the space-time-yield and the specific energy consumption of molten salt electrolysis processes for the electrowinning of metals in subgroups 4 and 5 of the periodic table of elements

    International Nuclear Information System (INIS)

    Disadvantages of molten salt electrolysis are its low space-time-yield (kg/m3 h) combined with its high specific energy consumption (kWh/kg). These factors essentially determine how electrolysis is applied on an industrial scale. The electrolysis of tantalum was selected as an example representative for other electrolytic processes; this series of tests allow statements also on the winning of the other elements from subgroups 4 and 5 of the periodic table, and on electrolytic aluminium extraction. Optimal operating conditions for direct current electrolysis were determined in the laboratory by varying the current density and the electrolysis temperature. In order to improve the space-time-yield from an existing electrolytic cell with a given electrolyte composition beyond the optimal range of direct current electrolysis, the process of periodic current reversal is applied. In this process, the polarity is reversed for a short time at constant periodic intervals. If the forward time period and the backward time period are chosen in a suitable way, both the current efficiency and the space-time-yield can be improved without increasing the energy consumption. 59 refs., 48 figs., 8 tabs. (Author)

  17. Evaluation of low cost cathode materials for treatment of industrial and food processing wastewater using microbial electrolysis cells

    KAUST Repository

    Tenca, Alberto

    2013-02-01

    Microbial electrolysis cells (MECs) can be used to treat wastewater and produce hydrogen gas, but low cost cathode catalysts are needed to make this approach economical. Molybdenum disulfide (MoS2) and stainless steel (SS) were evaluated as alternative cathode catalysts to platinum (Pt) in terms of treatment efficiency and energy recovery using actual wastewaters. Two different types of wastewaters were examined, a methanol-rich industrial (IN) wastewater and a food processing (FP) wastewater. The use of the MoS2 catalyst generally resulted in better performance than the SS cathodes for both wastewaters, although the use of the Pt catalyst provided the best performance in terms of biogas production, current density, and TCOD removal. Overall, the wastewater composition was more of a factor than catalyst type for accomplishing overall treatment. The IN wastewater had higher biogas production rates (0.8-1.8 m3/m3-d), and COD removal rates (1.8-2.8 kg-COD/m3-d) than the FP wastewater. The overall energy recoveries were positive for the IN wastewater (3.1-3.8 kWh/kg-COD removed), while the FP wastewater required a net energy input of -0.7 - 1.2 kWh/kg-COD using MoS 2 or Pt cathodes, and -3.1 kWh/kg-COD with SS. These results suggest that MoS2 is the most suitable alternative to Pt as a cathode catalyst for wastewater treatment using MECs, but that net energy recovery will be highly dependent on the specific wastewater. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  18. Evaluation of process parameters and membranes for SO2 electrolysis / Andries Johannes Krüger

    OpenAIRE

    Krüger, Andries Johannes

    2015-01-01

    The environmentally unsafe by-products (CO2, H2S, NOx and SO2 for example) of using carbon-based fuels for energy generation have paved the way for research on cleaner, renewable and possibly cheaper alternative energy production methods. Hydrogen gas, which is considered as an energy carrier, can be applied in a fuel cell setup for the production of electrical energy. Although various methods of hydrogen production are available, sulphur-based thermochemical processes (such as the Hybrid Sul...

  19. Electrolysis of oxalic acid in simulative mother liquor generated from plutonium (IV) oxalate precipitation process

    International Nuclear Information System (INIS)

    Cyclic voltammetry and linear voltammetry methods were used to study the characteristics of electrochemical behavior of oxalic acid (OA) and plutonium at platinum anode in simulative mother liquor (OW) generated from Pu (IV) oxalate precipitation step. The cyclic voltammograms show that the oxidation of OA on Pt anode is an irreversible reaction. An electrolytic method was described for the destruction of the OA in OW. 0.002-0.1 g/L Pu has no obvious effect on the destruction velocity of OA. Under a constant current density, OA can be destroyed to below 0.001 mol/L after a certain time, which can satisfy the requirements of the technical process. (authors)

  20. Use of sodium salt electrolysis in the process of continuous modification of eutectic EN AC-AlSi12 alloy

    Indian Academy of Sciences (India)

    J Pezda; A Białobrzeski

    2015-04-01

    This paper presents test results concerning the selection of sodium salt for the technology of continuous modification of the EN AC-AlSi12 alloy, which is based on electrolysis of sodium salts, occurring directly in a crucible with liquid alloy. Sodium ions formed as a result of the sodium salt dissociation and the electrolysis are 'transferred' through walls of the retort made of solid electrolyte. Upon contact with the liquid alloy, which functions as a cathode, sodium ions are transformed into the atomic state, modifying the alloy. As a measure of the alloy modification extent, the obtained increase of the tensile strength m and change of metallographic structure are used, confirming obtained modification effect of the investigated alloy.

  1. Hydrogen production coupled to nuclear waste treatment: the safe treatment of alkali metals through a well-demonstrated process

    International Nuclear Information System (INIS)

    In 1992, the United Nations emphasised the urgent need to act against the perpetuation of disparities between and within nations, the worsening of poverty, hunger, ill health and illiteracy and the continuing deterioration of ecosystems on which we depend for our well-being. In this framework, taking into account the preservation of both worldwide energy resources and ecosystems, the use of nuclear energy to produce clean energy carriers, such as hydrogen, is undoubtedly advisable. However, coping fully with the Agenda 21 statements requires defining adequate treatment processes for nuclear wastes. This paper discusses the possible use of a well-demonstrated process to convert radioactively contaminated alkali metals into sodium hydroxide while producing hydrogen. We conclude that a synergy between Chlor-Alkali specialists and nuclear specialists may help find an acceptable solution for radioactively contaminated sodium waste. (author)

  2. Plasma assisted measurements of alkali metal concentrations in pressurised combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland)

    1997-10-01

    In this project the continuous alkali measurement method plasma excited alkali resonance line spectroscopy (PEARLS) was developed, tested and demonstrated in pressurised combustion facilities. The PEARLS method has been developed at Tampere University of Technology (TUT). During 1994-1996 the PEARLS method was developed from the laboratory level to an industrial prototype. The alkali measuring instrument has been tested and used for regular measurements in four different pressurised combustion installations ranging up to industrial pilot scale. The installations are: (1) a pressurised entrained flow reactor (PEFR) at VTT Energy in Jyvaeskylae, Finland (2) a pressurised fluidised bed combustion facility, called FRED, at DMT in Essen, Germany. (3) a 10 MW pressurised circulating fluidised bed combustion pilot plant at Foster Wheeler Energia Oy in Karhula, Finland (4) PFBC Research Facility at ABB Carbon in Finspaang, Sweden

  3. Performance of a biogas upgrading process based on alkali absorption with regeneration using air pollution control residues.

    Science.gov (United States)

    Baciocchi, Renato; Carnevale, Ennio; Costa, Giulia; Gavasci, Renato; Lombardi, Lidia; Olivieri, Tommaso; Zanchi, Laura; Zingaretti, Daniela

    2013-12-01

    This work analyzes the performance of an innovative biogas upgrading method, Alkali absorption with Regeneration (AwR) that employs industrial residues and allows to permanently store the separated CO2. This process consists in a first stage in which CO2 is removed from the biogas by means of chemical absorption with KOH or NaOH solutions followed by a second stage in which the spent absorption solution is contacted with waste incineration Air Pollution Control (APC) residues. The latter reaction leads to the regeneration of the alkali reagent in the solution and to the precipitation of calcium carbonate and hence allows to reuse the regenerated solution in the absorption process and to permanently store the separated CO2 in solid form. In addition, the final solid product is characterized by an improved environmental behavior compared to the untreated residues. In this paper the results obtained by AwR tests carried out in purposely designed demonstrative units installed in a landfill site are presented and discussed with the aim of verifying the feasibility of this process at pilot-scale and of identifying the conditions that allow to achieve all of the goals targeted by the proposed treatment. Specifically, the CO2 removal efficiency achieved in the absorption stage, the yield of alkali regeneration and CO2 uptake resulting for the regeneration stage, as well as the leaching behavior of the solid product are analyzed as a function of the type and concentration of the alkali reagent employed for the absorption reaction. PMID:24045173

  4. Anodes for alkaline electrolysis

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  5. The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Guo, W., E-mail: guowei1982cry@163.com [College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Ma, H.A.; Jia, X. [National Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Appropriate etch processes of hBN and cBN under HPHT are proposed. • The degree of the crystallization of hBN was decreased. • A special cBN growth mechanism with a triangular unit is proposed. • Plate-shape cBN crystals with large ratio of length to thickness were obtained. • A strategy provides useful guidance for controlling the cBN morphology. - Abstract: Some new etching processes of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) under high pressure and high temperature in the presence of alkali and alkaline earth fluorides have been discussed. It is found that hBN is etched distinctly by alkali and alkaline earth fluorides and the morphology of hBN is significantly changed from plate-shape to spherical-shape. Based on the “graphitization index” values of hBN, the degree of the crystallization of hBN under high pressure and high temperature decreases in the sequence of LiF > CaF{sub 2} > MgF{sub 2}. This facilitates the formation of high-quality cBN single crystals. Different etch steps, pits, and islands are observed on cBN surface, showing the strong etching by alkali and alkaline earth fluorides and the tendency of layer-by-layer growth. A special layer growth mechanism of cBN with a triangular unit has been found. Furthermore, the morphologies of cBN crystals are apparently affected by a preferential surface etching of LiF, CaF{sub 2} and MgF{sub 2}. Respectively, the plate-shape and tetrahedral cBN crystals can be obtained in the presence of different alkali and alkaline earth fluorides.

  6. The etching process of boron nitride by alkali and alkaline earth fluorides under high pressure and high temperature

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Appropriate etch processes of hBN and cBN under HPHT are proposed. • The degree of the crystallization of hBN was decreased. • A special cBN growth mechanism with a triangular unit is proposed. • Plate-shape cBN crystals with large ratio of length to thickness were obtained. • A strategy provides useful guidance for controlling the cBN morphology. - Abstract: Some new etching processes of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) under high pressure and high temperature in the presence of alkali and alkaline earth fluorides have been discussed. It is found that hBN is etched distinctly by alkali and alkaline earth fluorides and the morphology of hBN is significantly changed from plate-shape to spherical-shape. Based on the “graphitization index” values of hBN, the degree of the crystallization of hBN under high pressure and high temperature decreases in the sequence of LiF > CaF2 > MgF2. This facilitates the formation of high-quality cBN single crystals. Different etch steps, pits, and islands are observed on cBN surface, showing the strong etching by alkali and alkaline earth fluorides and the tendency of layer-by-layer growth. A special layer growth mechanism of cBN with a triangular unit has been found. Furthermore, the morphologies of cBN crystals are apparently affected by a preferential surface etching of LiF, CaF2 and MgF2. Respectively, the plate-shape and tetrahedral cBN crystals can be obtained in the presence of different alkali and alkaline earth fluorides

  7. Possibility of application of solid oxide electrolysis cell on a smart iron-making process based on an active carbon recycling energy system

    International Nuclear Information System (INIS)

    Efficient carbon dioxide (CO2) reduction into carbon monoxide (CO) is required to establish a smart iron-making process based on an active carbon recycling energy system (iACRES). A disk-type solid oxide electrolysis cell (SOEC) was prepared and examined experimentally for application to the CO2 reduction process in iACRES. A SOEC with a cathode|electrolyte|anode structure of Ni-YSZ|YSZ|La0.6Sr0.4Co0.2Fe0.8O3-δ was fabricated. The electrolysis of carbon dioxide was conducted at 800-900°C. A current density of 107.1 mA cm-2 was measured between the cathode and anode at 900°C and at 2.52 V. The production rates of CO and O2 were in agreement with the theoretical values determined using Faraday's law. Evaluation of iACRES using the experimental results indicated that an estimated 0.73 high-temperature gas cooled reactor units as the primary energy source for CO2 reduction and a SOEC surface area of 0.098 km2 were required for the reduction of 30% CO2 in blast furnace gas emitted from a conventional blast furnace. (author)

  8. Process Demonstration For Lunar In Situ Resource Utilization-Molten Oxide Electrolysis (MSFC Independent Research and Development Project No. 5-81)

    Science.gov (United States)

    Curreri, P. A.; Ethridge, E. C.; Hudson, S. B.; Miller, T. Y.; Grugel, R. N.; Sen, S.; Sadoway, D. R.

    2006-01-01

    The purpose of this Focus Area Independent Research and Development project was to conduct, at Marshall Space Flight Center, an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis process to produce oxygen and metal. In essence, the vision was to develop two key technologies, the first to produce materials (oxygen, metals, and silicon) from lunar resources and the second to produce energy by photocell production on the Moon using these materials. Together, these two technologies have the potential to greatly reduce the costs and risks of NASA s human exploration program. Further, it is believed that these technologies are the key first step toward harvesting abundant materials and energy independent of Earth s resources.

  9. Recovery of alumina and alkali in Bayer red mud by the formation of andradite-grossular hydrogarnet in hydrothermal process.

    Science.gov (United States)

    Zhang, Ran; Zheng, Shili; Ma, Shuhua; Zhang, Yi

    2011-05-30

    Bayer red mud (RM) is an alumina refinery waste product rich in aluminum oxides and alkalis which are present primarily in the form of sodium hydro-aluminosilicate desilication product (DSP). A hydrothermal process was employed to recover alumina and alkali from "Fe-rich" and "Fe-lean" RM, the two representative species of RM produced in China. The hydrothermal process objective phase is andradite-grossular hydrogarnet characterized by the isomorphic substitution of Al and Fe. Batch experiments were used to evaluate the main factors influencing the recovery process, namely reaction temperature, caustic ratio (molar ratio of Na(2)O to Al(2)O(3) in sodium solution), sodium concentration and residence time. The results revealed that the Na(2)O content of 0.5 wt% and A/S of 0.3 (mass ratio of Al(2)O(3) to SiO(2)) in leached residue could be achieved with Fe-rich RM under optimal conditions. However, the hydrothermal treatment of Fe-lean RM proved less successful unless the reaction system was enriched with iron. Subsequent experiments examined the effects of the ferric compound's content and type on the substitution ratio. PMID:21444152

  10. Structural and Magnetic Diversity in Alkali-Metal Manganate Chemistry: Evaluating Donor and Alkali-Metal Effects in Co-complexation Processes.

    Science.gov (United States)

    Uzelac, Marina; Borilovic, Ivana; Amores, Marco; Cadenbach, Thomas; Kennedy, Alan R; Aromí, Guillem; Hevia, Eva

    2016-03-24

    By exploring co-complexation reactions between the manganese alkyl Mn(CH2 SiMe3 )2 and the heavier alkali-metal alkyls M(CH2 SiMe3 ) (M=Na, K) in a benzene/hexane solvent mixture and in some cases adding Lewis donors (bidentate TMEDA, 1,4-dioxane, and 1,4-diazabicyclo[2,2,2] octane (DABCO)) has produced a new family of alkali-metal tris(alkyl) manganates. The influences that the alkali metal and the donor solvent impose on the structures and magnetic properties of these ates have been assessed by a combination of X-ray, SQUID magnetization measurements, and EPR spectroscopy. These studies uncover a diverse structural chemistry ranging from discrete monomers [(TMEDA)2 MMn(CH2 SiMe3 )3 ] (M=Na, 3; M=K, 4) to dimers [{KMn(CH2 SiMe3 )3 ⋅C6 H6 }2 ] (2) and [{NaMn(CH2 SiMe3 )3 }2 (dioxane)7 ] (5); and to more complex supramolecular networks [{NaMn(CH2 SiMe3 )3 }∞ ] (1) and [{Na2 Mn2 (CH2 SiMe3 )6 (DABCO)2 }∞ ] (7)). Interestingly, the identity of the alkali metal exerts a significant effect in the reactions of 1 and 2 with 1,4-dioxane, as 1 produces coordination adduct 5, while 2 forms heteroleptic [{(dioxane)6 K2 Mn2 (CH2 SiMe3 )4 (O(CH2 )2 OCH=CH2 )2 }∞ ] (6) containing two alkoxide-vinyl anions resulting from α-metalation and ring opening of dioxane. Compounds 6 and 7, containing two spin carriers, exhibit antiferromagnetic coupling of their S=5/2 moments with varying intensity depending on the nature of the exchange pathways. PMID:26916525

  11. Electrolysis resistance reduced by magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, R.N. [Victoria Univ., Victoria, BC (Canada). Dept. of Chemistry

    2009-07-01

    The production of hydrogen by electrolysis of water has been known for many years, and the Nernst equation has been used to produce pressurized hydrogen. It has also been thought that the cost of hydrogen produced by electrolysis is higher than by steam reduction of natural gas. However, the consensus of opinion in research efforts is that hydrogen is at least 2.5 times the cost of gasoline per watt hour of energy. This paper described an experiment that used the main attributes of a cell outlined from Kirk-Othmer. Since the cell was difficult to construct and insufficient data was collected on the magnetohydrodynamic (MHD) process, a simpler, easily portable demonstration cell was devised. Experiments were run and the data were plotted both as impressed voltage at constant current versus time and resistance at constant current versus time. The cells were small, the electrolyte was enough to flood the cell and allow egress of hydrogen and oxygen. Since much of the raw data needed for a real calculation applicable to the industry was absent, only laboratory scale MHD scale experimental data was presented, and the volatile cost of petroleum was not assessed or included. It was not possible to claim that hydrogen was as cheap as gasoline for internal combustion engines or fuel cell cars, but water electrolysis in MHD conditions clearly rated consideration. 2 figs.

  12. Investigation the Efficiency of Electrolysis Process using 3 Dimensional Graphite Electrodes for Decolonization of Phenolphthalein and Phenol red from Aqueous Environments

    Directory of Open Access Journals (Sweden)

    Mohmmad Reza Massoudinejad

    2012-10-01

    Full Text Available Background and Objectives: The presence of chemical dyes in the water resources not only pollutes them, but also brings about death of organisms and serious indemnities to the environment through stopping oxygen production and preventing penetration of the sunlight. In this study, we investigated the efficiency of the electrolysis process for decolonization of phenolphthalein and phenol red from aqueous environment. Materials and Methods: The experiments were conducted in an electrochemical reactor having a working volume of 1 liter equipped with 2 graphite electrodes. This study was conducted at laboratory scale. Samples were prepared by dissolving two phenol red and phenolphthalein dyes in drinking water. Then, the effect of operating parameters such as voltage, inter-electrode distance, and NaCl concentration on the complete dye removal was determined considering optimum retention time using  Factorial variance analyses and the graphs were plotted using MS Excel software.Results: the results showed that the optimum conditions for completely removal of phenolphthalein was achieved applying a voltage of 48 V, the retention time of 9 minutes, 5 cm inter-electrode distance, and the salt concentration of 1.5 g/l, whereas, complete removal of phenol red was achieved applying a voltage of 48 V, the retention time of 8 minutes, 5 cm inter-electrode distance, and the salt concentration of 2 g/l. Under these conditions, COD removal efficiency for phenol red and phenolphthalein was 85 and 80 percent respectively.Conclusion: This study revealed that electrolysis process is an effective method to remove both phenolphthalein and phenol red dyes from effluent, because it can completely remove the dyes in a short time.

  13. A study on the electrolysis of sulfur dioxide and water for the sulfur cycle hydrogen production process

    Science.gov (United States)

    1980-01-01

    Experimental electrolysis cells using various platinum catalyzed carbon electrodes were tested. When operated at 200 mA/sq cm current density using 50 w/o acid at 50 C and 1 atm, a reference cell required 1.22 volts and degraded rapidly. After several improvements were incorporated into electrodes and the test cell configuration, a later cell required only 0.77 volts under identical operating conditions. At a lower current density, 100 mA/sq cm, the cell required only 0.63 volts. Kinetic studies on metal electrodes, measurements of temperature effects on electrode kinetics, investigations of electrocatalytic activities of metal electrodes over a wide range of acid concentrations, cyclic voltametric studies and evaluation of alternate catalysts were also conducted. From diffusivity experiments, a cation exchange membrane material, P-4010, exhibited an excellent diffusion coefficient, more than two orders of magnitude lower than that of rubber. Ionic resistivity measurements of eight materials showed that microporous rubber had the lowest resistivity.

  14. Cathodic processes of platinum electrodes during Na2MoO3-MoO3 melt electrolysis

    International Nuclear Information System (INIS)

    It has been shown previously that during polarization of a platinum cathode in the Na2MoO4-MoO3 system the evolution of molybdenum dioxide is preceded by a wave which, in the authors' opinion, can be attributed to changes in ionic composition of the melt layer next to the cathode, and in particular to the appearance of lower, reduced forms of the ions. In tungstate melts, the evolution of bronze or other products is preceded by alloy electrolysis of molybdate melts. The present work was undertaken in order to elucidate the conditions under which a platinum electrode can be used as an indicator electrode for electrochemical investigations in molybdate melts. The experiments used ''chemically pure'' MoO3 and ''analytically pure'' Na2MoO4.2H2O. On the basis of the investigation it is concluded that alloys of platinum with molybdenum are formed at the cathode when the melt contains relatively small amounts of MoO3

  15. Tuning indium tin oxide work function with solution-processed alkali carbonate interfacial layers for high-efficiency inverted organic photovoltaic cells

    International Nuclear Information System (INIS)

    Selective electron collection by an interfacial layer modified indium tin oxide cathode is critically important for achieving high-efficiency inverted structure organic photovoltaic (OPV) cells. Here, we demonstrate that solution-processed alkali carbonates, such as Li2CO3, Na2CO3, K2CO3, Rb2CO3, Cs2CO3, are good interfacial layer materials. Both carbonate concentration and annealing conditions can affect cathode work function and surface roughness. By proper optimization, different alkali carbonates can be almost equally effective as the cathode interfacial layer. Furthermore, good device performance can be achieved at a low annealing temperature (<50 ° C), which allows for potential applications in solution-processed inverted OPV cells on plastic substrates. This work indicates that alkali carbonates, not just cesium carbonate, are valid choices as the cathode interlayer in inverted OPV devices. (paper)

  16. Fabrication of large-scale single-crystal bismuth telluride (Bi2Te3) nanosheet arrays by a single-step electrolysis process

    Science.gov (United States)

    Tsai, Hung-Wei; Wang, Tsang-Hsiu; Chan, Tsung-Cheng; Chen, Pei-Ju; Chung, Chih-Chun; Yaghoubi, Alireza; Liao, Chien-Neng; Diau, Eric Wei-Guang; Chueh, Yu-Lun

    2014-06-01

    Nanolizing of thermoelectric materials is one approach to reduce the thermal conductivity and hence enhance the figure of merit. Bismuth telluride (Bi2Te3)-based materials have excellent figure of merit at room temperature. For device applications, precise control and rapid fabrication for the nanostructure of thermoelectric materials are essential issues. In the present study, we demonstrate a one-step electrolysis process to directly form Bi2Te3 nanosheet arrays (NSAs) on the surface of bulk Bi2Te3 with controllable spacing distance and depth by tuning the applied bias and duration. The single sheet of NSAs reveals that the average thickness and electrical resistivity of single crystalline Bi2Te3 in composition are 399.8 nm and 137.34 μΩ m, respectively. The formation mechanism of NSAs has been proposed. A 1.12% efficiency of quantum dot-sensitized solar cells with Bi2Te3 NSAs for counter electrode has been demonstrated, indicating that Bi2Te3 NSAs from top-down processing with a high ratio of surface area to volume are a promising candidate for possible applications such as thermoelectrics, dye-sensitized solar cells (DSSCs), and lithium-ion batteries.Nanolizing of thermoelectric materials is one approach to reduce the thermal conductivity and hence enhance the figure of merit. Bismuth telluride (Bi2Te3)-based materials have excellent figure of merit at room temperature. For device applications, precise control and rapid fabrication for the nanostructure of thermoelectric materials are essential issues. In the present study, we demonstrate a one-step electrolysis process to directly form Bi2Te3 nanosheet arrays (NSAs) on the surface of bulk Bi2Te3 with controllable spacing distance and depth by tuning the applied bias and duration. The single sheet of NSAs reveals that the average thickness and electrical resistivity of single crystalline Bi2Te3 in composition are 399.8 nm and 137.34 μΩ m, respectively. The formation mechanism of NSAs has been proposed. A 1

  17. Development and testing of on-line analytical instrumentation for alkali and heavy metal release in pressurised conversion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V.; Oikari, R. [Tampere Univ. of Technology (Finland)

    1997-10-01

    The purpose of the project is to demonstrate in industrial conditions and further develop the continuous alkali measurement method plasma excited alkali resonance line spectroscopy (PEARLS) developed at Tampere University of Technology (TUT). The demonstration takes place in joint measuring campaigns, where two other continuous alkali measurement methods, ELIF and surface ionisation, are being simultaneously demonstrated. A modification of PEARLS will also be developed for the continuous measurement of heavy metal concentrations. A market study of continuous measuring techniques for alkali and heavy metals is further part of the project. The method will be demonstrated in two pressurised fluidised bed combustion facilities. One of these is the 10 MW PCFB of Foster Wheeler Energia Oy in Karhula. The second one is yet to be decided. The first measuring campaign is scheduled for the spring of 1997 in Karhula. In 1996 the group at TUT participated in the performance of a market study regarding continuous measuring techniques for alkali and heavy metal concentrations. A draft report was submitted to and approved by the EC. Development work on PEARLS in 1996 has centered around the construction of a calibration device for alkali measurements. The device can be used by all three measuring techniques in the project to check readings against a known alkali concentration at controlled and known conditions. In 1996 PEARLS was applied for alkali measurement at several pressurised combustion installations of laboratory and industrial pilot scale

  18. Effect of Na3PO4 on the Hydration Process of Alkali-Activated Blast Furnace Slag

    Directory of Open Access Journals (Sweden)

    Lukáš Kalina

    2016-05-01

    Full Text Available In recent years, the utilization of different non-traditional cements and composites has been increasing. Alkali-activated cementitious materials, especially those based on the alkali activation of blast furnace slag, have considerable potential for utilization in the building industry. However, alkali-slag cements exhibit very rapid setting times, which are too short in some circumstances, and these materials cannot be used for some applications. Therefore, it is necessary to find a suitable retarding admixture. It was shown that the sodium phosphate additive has a strong effect on the heat evolution during alkali activation and effectively retards the hydration reaction of alkali-activated blast furnace slag. The aim of the work is the suggestion of a reaction mechanism of retardation mainly based on Raman and X‑ray photoelectron spectroscopy.

  19. Fabrication of large-scale single-crystal bismuth telluride (Bi₂Te₃) nanosheet arrays by a single-step electrolysis process.

    Science.gov (United States)

    Tsai, Hung-Wei; Wang, Tsang-Hsiu; Chan, Tsung-Cheng; Chen, Pei-Ju; Chung, Chih-Chun; Yaghoubi, Alireza; Liao, Chien-Neng; Diau, Eric Wei-Guang; Chueh, Yu-Lun

    2014-07-21

    Nanolizing of thermoelectric materials is one approach to reduce the thermal conductivity and hence enhance the figure of merit. Bismuth telluride (Bi₂Te₃)-based materials have excellent figure of merit at room temperature. For device applications, precise control and rapid fabrication for the nanostructure of thermoelectric materials are essential issues. In the present study, we demonstrate a one-step electrolysis process to directly form Bi₂Te₃ nanosheet arrays (NSAs) on the surface of bulk Bi₂Te₃ with controllable spacing distance and depth by tuning the applied bias and duration. The single sheet of NSAs reveals that the average thickness and electrical resistivity of single crystalline Bi₂Te₃ in composition are 399.8 nm and 137.34 μΩ m, respectively. The formation mechanism of NSAs has been proposed. A 1.12% efficiency of quantum dot-sensitized solar cells with Bi₂Te₃ NSAs for counter electrode has been demonstrated, indicating that Bi₂Te₃ NSAs from top-down processing with a high ratio of surface area to volume are a promising candidate for possible applications such as thermoelectrics, dye-sensitized solar cells (DSSCs), and lithium-ion batteries. PMID:24770854

  20. Optimum conditions for the formation of Al13 polymer and active chlorine in electrolysis process with Ti/RuO2-TiO2 anodes.

    Science.gov (United States)

    Hu, Chengzhi; Liu, Huijuan; Qu, Jiuhui

    2012-01-01

    A polyaluminum containing a high concentration of Al13 polymer and active chlorine (PACC) was successfully synthesized by a new electrochemical reactor using Ti/RuO2-TiO2 anodes. PACC can potentially be used as a dual-function chemical reagent for water treatment. The obtained results indicated that the formation of Al13 polymer and active chlorine, were the most active components in PACC responsible for coagulation and disinfection respectively. These components were significantly influenced by electrolyte temperature, current density, and stirring rate. It was observed that high electrolyte temperature favored the formation of Al13. Increasing current density and stirring rate resulted in high current efficiency of chlorine evolution, thus favoring the generation of Al13 and active chlorine in PACC. When the PACC (Al(T) = 0.5 mol/L, basicity = 2.3) was prepared at the optimum conditions by electrolysis process, the Al13 polymer and active chlorine in product reached above 70% of Al(T) and 4000 mg/L, respectively. In the pilot scale experiment with raw polyaluminum chloride used as an electrolyte, PACC was successfully prepared and produced a high content of Al13 and active chlorine products. The pilot scale experiment demonstrated a potential industrial approach of PACC preparation. PMID:22655391

  1. Treatment of nanofiltration concentrates of mature landfill leachate by a coupled process of coagulation and internal micro-electrolysis adding hydrogen peroxide.

    Science.gov (United States)

    Huang, Jingang; Chen, Jianjun; Xie, Zhengmiao; Xu, Xiaojun

    2015-01-01

    In this study, a coupled process of coagulation and aerated internal micro-electrolysis (IME) with the in situ addition of hydrogen peroxide (H2O2) was investigated for the treatment of nanofiltration (NF) concentrate from mature landfill leachate. The acceptable operating conditions were determined as follows: initial pH 4, polymeric aluminium chloride dosage of 525 mg-Al2O3/L in the coagulation process, H2O2 dosage of 0.75 mM and an hydraulic retention time of 2 h in an aerated IME reactor. As a result, the removal efficiencies for chemical oxygen demand (COD), total organic carbon, UV254 and colour were 79.2%, 79.6%, 81.8% and 90.8%, respectively. In addition, the ratio of biochemical oxygen demand (BOD5)/COD in the final effluent increased from 0.03 to 0.31, and that of E2/E4 from 12.4 to 38.5, respectively. The results indicate that the combined process is an effective and economical way to remove organic matters and to improve the biodegradability of the NF concentrate. Coagulation process reduces the adverse impact of high-molecular-weight organic matters such as humic acids, on the aerated IME process. A proper addition of H2O2 in the aerated IME can promote the corrosion of solid iron (Fe2+/Fe3+) and cause a likely domino effect in the enhancement of removal efficiencies. PMID:25270868

  2. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described in the...

  3. Improvements on water washing and alkali washing process for chlorobenzene production%氯化苯生产装置水碱洗工艺改造

    Institute of Scientific and Technical Information of China (English)

    祁方

    2015-01-01

    对氯化苯生产装置水碱洗工艺进行改造:将原一级水洗改为二级水洗,使水洗过程最大幅度地萃取出氯化液中的氯化氢、FeCl 3,减少碱洗过程耗碱量;在每一洗涤泵出口增加管道静态混合器,加强水碱洗混合分离效果;水碱洗废水循环利用,回收水洗废酸水中的FeCl3作为氯化反应催化剂,减少装置运行成本。%Water washing and alkali washing process for chlorobenzene production was improved .The original one-step water washing process was changed into a two-step process in order to extract the hydro-gen chloride and ferric trichloride to the greatest extent from chlorination liquor and in order to reduce al-kali consumption during alkali washing .Pipe static mixers were installed at the outlets of every washing pump to strengthen the mixing and separating effects during water washing and alkali washing .The waste water from water washing and alkali washing was used repeatedly , and ferric trichloride contained in waste acidic water formed during water washing was recovered and used as catalyst for chlorination to re -duce operation cost.

  4. Studies on membrane acid electrolysis for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marco Antonio Oliveira da; Linardi, Marcelo; Saliba-Silva, Adonis Marcelo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio], Email: saliba@ipen.br

    2010-07-01

    Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The electrolysis by membrane has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with noncarbogenic causing no harm by producing gases deleterious to the environment. (author)

  5. Large Scale Inert Anode for Molten Oxide Electrolysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Molten oxide electrolysis is a demonstrated laboratory-scale process for producing oxygen from the JSC-1a lunar simulant; however, critical subsystems necessary for...

  6. A Demonstration of Carbon-Assisted Water Electrolysis

    Directory of Open Access Journals (Sweden)

    Olalekan D. Adeniyi

    2013-03-01

    Full Text Available It is shown that carbon fuel cell technology can be combined with that of high temperature steam electrolysis by the incorporation of carbon fuel at the cell anode, with the resulting reduction of the required electrolysis voltage by around 1 V. The behaviour of the cell current density and applied voltage are shown to be connected with the threshold of electrolysis and the main features are compared with theoretical results from the literature. The advantage arises from the avoidance of efficiency losses associated with electricity generation using thermal cycles, as well as the natural separation of the carbon dioxide product stream for subsequent processing.

  7. Extraction of vanadium and alkali metals in the processing of spent catalysts

    OpenAIRE

    Нікіфорова, Анна Юріївна; Кожура, Олег Вікторович; Пасенко, Олександр Олександрович

    2016-01-01

    The authors proposed the technological scheme of complex processing of spent vanadium catalysts for the synthesis of sulfuric acid. They studied the process of reductive leaching by sulfur dioxide and estimated the effect of the acidity of the solutions, the amount of reducing agent, the catalyst particle size and temperature on the degree of vanadium removal. The main parameters affecting the completeness of removal are temperature and acidity of solutions, the role of other factors is insig...

  8. Multi-objective optimization of two alkali catalyzed processes for biodiesel from waste cooking oil

    International Nuclear Information System (INIS)

    Highlights: • Biodiesel processes use waste cooking oil and are close to industrial practice. • Detailed constituents of waste cooking oil and detailed kinetics are used. • Two complete processes are optimized for economic and environmental objectives. • Obtained trade-offs provide deeper understanding and alternative optimal solutions. - Abstract: In view of the finite availability and environmental concerns of fossil fuels, biodiesel is one of the promising fuel alternatives. This study considers waste cooking palm oil with 6% free fatty acids (FFA) as feed-stock, which facilitates its better utilization and promotes sustainability. Two biodiesel production processes (both involving esterification catalyzed by sulfuric acid and trans-esterification catalyzed by sodium hydroxide) are compared for economic and environmental objectives. Firstly, these processes are simulated, considering detailed constituents of palm oil and also detailed kinetics for both esterification and trans-esterification, in Aspen Plus simulator. Subsequently, both the processes are optimized considering profit, heat duty and organic waste as objectives, and using an Excel-based multi-objective optimization (EMOO) program for the elitist non-dominated sorting genetic algorithm-II (NSGA-II). The results show that the profit improves with the increase in heat duty, and that the profit increase is accompanied by larger amount of organic waste. Process 1 having three trans-esterification reactors produces significantly lower organic waste (by 32%), requires lower heat duty (by 39%) and slightly more profitable (by 1.6%) compared to Process 2 having a single trans-esterification reactor and also a different separation sequence. Overall, the obtained quantitative trade-offs between objectives enable better decision making about the process design for biodiesel production from waste cooking oil

  9. Hydrogen production by high-temperature electrolysis of water vapor steam. Test results obtained with an electrolysis tube

    International Nuclear Information System (INIS)

    High-temperature electrolysis of water vapor steam is an advanced hydrogen production process decomposing high temperature steam up to 1,000degC, which applies an electro-chemical reaction reverse to the solid oxide fuel cell. At Japan Atomic Energy Research Institute, laboratory-scale experiments have been conducted using a practical electrolysis tube with 12 electrolysis cells in order to develop heat utilization systems for high-temperature gas-cooled reactors. The electrolysis cells of which electrolyte was yttria-stabilized zirconia were formed on a porous ceramic tube in series by plasma spraying. In the experiments, water steam mixed with argon carrier gas was supplied into the electrolysis tube heated at a constant temperature regulated in the range from 850degC to 950degC, and electrolysis power was supplied by a DC power source. Hydrogen production rate increased with applied voltage and electrolysis temperature; the maximum production rate was 6.9Nl/h at 950degC. Hydrogen production rate was correlated with applied current densities on the basis of experimental data. High energy efficiency was achieved under the applied current density ranging from 80 to 100 mA/cm2. (author)

  10. Properties of the argentine anchovy and withemouth croaker muscle proteins obtained by alkali solubization process

    Directory of Open Access Journals (Sweden)

    Irene Rodrigues Freitas

    2014-07-01

    Full Text Available The aim of this study was to evaluate functional properties and microbiological characteristics of recovered proteins of anchovy (Engraulis anchoita and whitemouth croaker (Micropogonias furnieri through the process of alkaline solubilization and isoelectric precipitation, using different solubilization at pH 11 (NaOH and KOH and precipitation at pH 5.5 (HCl and H3PO4 reagents. Analyses of water holding capacity were carried out (at pH 3,5,7,9 and 11, oil holding capacity and Salmonella sp, Escherichia coli and Staphylococcus aureus. The water holding capacity was lowest at pH 5. The low value of the proteins recovered by alkaline solubilization process also indicates changes in the protein. The highest oil holding capacity was observed in whitemouth croaker concentrates (NaOH/H3PO4 at 5.6 ml oil/g protein. As for microbiological analyses, results showed no Salmonella in 25 g for all treatments and maximum count of 2.75 x 102 CFU/g for coagulase positive Staphylococcus for the muscle of anchovy concentrated. The protein concentrate obtained by combining NaOH/H3PO4 showed better functional quality. This process is an alternative to recover fish protein of low commercial value that may be used as an ingredient in foods.

  11. Upgrading platform using alkali metals

    Science.gov (United States)

    Gordon, John Howard

    2014-09-09

    A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  12. Hydrogen production from sugar beet juice using an integrated biohydrogen process of dark fermentation and microbial electrolysis cell.

    Science.gov (United States)

    Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Hafez, Hisham; Lee, Hyung-Sool

    2015-12-01

    An integrated dark fermentation and microbial electrochemical cell (MEC) process was evaluated for hydrogen production from sugar beet juice. Different substrate to inoculum (S/X) ratios were tested for dark fermentation, and the maximum hydrogen yield was 13% of initial COD at the S/X ratio of 2 and 4 for dark fermentation. Hydrogen yield was 12% of initial COD in the MEC using fermentation liquid end products as substrate, and butyrate only accumulated in the MEC. The overall hydrogen production from the integrated biohydrogen process was 25% of initial COD (equivalent to 6 mol H2/mol hexoseadded), and the energy recovery from sugar beet juice was 57% using the combined biohydrogen. PMID:26398665

  13. An experimental study of charge exchange process in the energy range 1-30 keV during the passage of alkali metal ions and atoms through cesium and potassium vapour

    International Nuclear Information System (INIS)

    An experimental study is presented of the charge exchange processes in the energy range of about 1-30 keV during the passage of positive alkali ions and alkali atoms through potassium and cesium vapour. The experimental set-up designed for this experiment includes a thermionic source for positive alkali ions with an acceleration stage, a first charge exchange cell to produce fast alkali atoms, a second charge exchange cell with a surface ionisation detector to determine the alkali metal vapor target thickness and a detection system with electrostatic bending of the charged secondary species. The maximum negative ion yield has been determined for the collision systems Li+ + K, Na+ + K, K+ + K, and Rb+ + K, and for another eleven systems the charge transfer cross-sections have been measured too. (orig./GG)

  14. Viscose production : Impact from alkali resistance (R18) and hemicellulose content in dissolving cellulose on the processability and quality of viscose.

    OpenAIRE

    Hellström, Sara

    2012-01-01

    In this study the influence of variations in alkali resistance (R18) of cellulose on the quality of the viscose product in terms of carbohydrate content have been examined. The dissolution pattern of hemicellulose in the first steps of the viscose process with different running parameters has been determined. Furthermore the correlation between R18 and hemicellulose content has been studied. Mercerization and pressing was performed in a viscose micro plant at MoRe Research with varying proces...

  15. An efficient hybrid sulfur process using PEM electrolysis with a bayonet decomposition reactor - HTR2008-58207

    International Nuclear Information System (INIS)

    The Hybrid Sulfur (HyS) Process is being developed to produce hydrogen by water-splitting using heat from advanced nuclear reactors. It has the potential for high efficiency and competitive hydrogen production cost, and has been demonstrated at a laboratory scale. As a two-step process, the HyS is one of the simplest thermochemical cycles. The sulfuric acid decomposition reaction is common to all sulfur cycles, including the Sulfur-Iodine (SI) cycle. What distinguishes the HyS Process from the other sulfur cycles is the use of sulfur dioxide (SO2) to depolarize the anode of a water electrolyzer. The two critical HyS Process components are the SO2- depolarized electrolyzer (SDE), and the high-temperature decomposition reactor. A proton exchange membrane (PEM)- type SDE and a silicon carbide bayonet-type high-temperature decomposition reactor are being developed for DOE's Nuclear Hydrogen Initiative (NHI) by Savannah River National Laboratory (SRNL) and by Sandia National Laboratories (SNL), respectively. The ultimate goal of the NHI-sponsored work is to couple the SDE and the reactor in an integrated laboratory scale experiment to prove the technical readiness of the HyS cycle for the NGNP demonstration. This paper describes the flowsheet that is being prepared to combine these two components into a viable process and presents the latest performance projections and economics for a HyS Process coupled to a PBMR heat source. The basic flowsheet for this process has been described elsewhere [4]. It requires an acid concentration section because the SDE product, which is limited to no more than 50% H2SO4 by cell voltage considerations, is too dilute to be fed directly to the bayonet, which needs at least 65% H2SO4 in the feed for acceptable performance. Optimization involved trade-offs between decomposition reaction and acid concentration heat requirements. The PBMR heat source can split its heat output between the decomposition reaction and either steam (which could be

  16. Production of Biodiesel Fuel from Waste Soya bean Cooking Oil by Alkali Trans-esterification Process

    Directory of Open Access Journals (Sweden)

    Ajinkya Dipak Deshpande*,

    2016-04-01

    Full Text Available Biodiesel is biodegradable, clean-burning, non-toxic, renewable, high-quality, and cheap diesel fuel made primarily from waste vegetable oil which can be used without any alterations in engine design. The paper is concerned with the extraction and quality evaluation of the biodiesel fuels synthesized from waste soya bean cooking oil. Waste soya bean cooking oil had high amount of free fatty acid. Thus, single step transesterification process with the aid of homogeneous catalyst as 1% potassium hydroxide were implemented in this experiment. Methanol was chosen as alcohol solvent. In the transesterification process, the triglycerides in waste cooking oil was reacted with a methanol to form esters and glycerol as by product.The biodiesel were extracted for different oil to methanol ratio as 1:2, 1:3 and 1:4. The highest biodiesel yield of 76% was obtained at 1:3 volumetric ratio for 60 ºC reaction temperature and 1250 rpm stirring speed. Results show that the optimal methyl ester yield of 90% occurred at methanol: oil volume ratio of 3:1. The product met the ASTM fuel standards for relative density, acid value, relative density, calorific value, flash point and kinematic viscosity.

  17. Hydrogen Production from Nuclear Energy via High Temperature Electrolysis

    International Nuclear Information System (INIS)

    This paper presents the technical case for high-temperature nuclear hydrogen production. A general thermodynamic analysis of hydrogen production based on high-temperature thermal water splitting processes is presented. Specific details of hydrogen production based on high-temperature electrolysis are also provided, including results of recent experiments performed at the Idaho National Laboratory. Based on these results, high-temperature electrolysis appears to be a promising technology for efficient large-scale hydrogen production

  18. Radiation-induced processes and defects in alkali and alkaline-earth borate crystals

    International Nuclear Information System (INIS)

    The paper presents the results of a study of the radiation-induced processes and defects in nonlinear optical crystals Li2B4O7 (LTB), LiB3O5 (LBO), CsLiB6O10, KB5O8·4H2O, β-BaB2O4. It was revealed that a pulsed electron beam irradiation at 290 K forms the radiation-induced pairs of the 'vacancy--interstitial atom' defects in the cation sublattice of these crystals. This gives rise to a creation of metastable electronic (interstitial atom) and hole (small-radius polaron near the cation vacancy) centers in high concentrations. Optical hole-transitions from the local level of the trapped hole centers to the valence band states are responsible for the transient optical absorptions (TOA) of borates in the visible and UV spectral ranges. A sublattice of the weakly bound mobile lithium cations in LTB and LBO favors a spatial separation of the radiation-induced pair defects 'hole polaron near Li-vacancy--mobile interstitial Li0 atom'. Their decay rated by the electron-hole nonradiative tunnel recombination determines a peculiar feature of the TOA decay kinetics in LTB and LBO

  19. Hydrogen Generation From Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Steven Cohen; Stephen Porter; Oscar Chow; David Henderson

    2009-03-06

    Small-scale (100-500 kg H2/day) electrolysis is an important step in increasing the use of hydrogen as fuel. Until there is a large population of hydrogen fueled vehicles, the smaller production systems will be the most cost-effective. Performing conceptual designs and analyses in this size range enables identification of issues and/or opportunities for improvement in approach on the path to 1500 kg H2/day and larger systems. The objectives of this program are to establish the possible pathways to cost effective larger Proton Exchange Membrane (PEM) water electrolysis systems and to identify areas where future research and development efforts have the opportunity for the greatest impact in terms of capital cost reduction and efficiency improvements. System design and analysis was conducted to determine the overall electrolysis system component architecture and develop a life cycle cost estimate. A design trade study identified subsystem components and configurations based on the trade-offs between system efficiency, cost and lifetime. Laboratory testing of components was conducted to optimize performance and decrease cost, and this data was used as input to modeling of system performance and cost. PEM electrolysis has historically been burdened by high capital costs and lower efficiency than required for large-scale hydrogen production. This was known going into the program and solutions to these issues were the focus of the work. The program provided insights to significant cost reduction and efficiency improvement opportunities for PEM electrolysis. The work performed revealed many improvement ideas that when utilized together can make significant progress towards the technical and cost targets of the DOE program. The cell stack capital cost requires reduction to approximately 25% of today’s technology. The pathway to achieve this is through part count reduction, use of thinner membranes, and catalyst loading reduction. Large-scale power supplies are available

  20. Micro-electrolysis technology for industrial wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of wastewater from pharmaceutical, dye-printing and papermaking plants. Results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis. For the use of micro-electrolysis in treatment of dye-printing wastewater, the removal rates of both chromaticity and COD were increased from neutral condition to acid condition for disperse blue wastewater; more than 90% of chromaticity and more than 50% of COD could be removed in neutral condition for vital red wastewater.

  1. Electric field-induced softening of alkali silicate glasses

    International Nuclear Information System (INIS)

    Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown

  2. Electric field-induced softening of alkali silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, C.; Heffner, W.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Tessarollo, R.; Raj, R. [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)

    2015-11-02

    Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.

  3. Alkali metal sources for OLED devices

    Science.gov (United States)

    Cattaneo, Lorena; Longoni, Giorgio; Bonucci, Antonio; Tominetti, Stefano

    2005-07-01

    In OLED organic layers electron injection is improved by using alkali metals as cathodes, to lower work function or, as dopants of organic layer at cathode interface. The creation of an alkali metal layer can be accomplished through conventional physical vapor deposition from a heated dispenser. However alkali metals are very reactive and must be handled in inert atmosphere all through the entire process. If a contamination takes place, it reduces the lithium deposition rate and also the lithium total yield in a not controlled way. An innovative alkali metal dispensing technology has been developed to overcome these problems and ensure OLED alkali metal cathode reliability. The alkali Metal dispenser, called Alkamax, will be able to release up to a few grams of alkali metals (in particular Li and Cs) throughout the adoption of a very stable form of the alkali metal. Lithium, for example, can be evaporated "on demand": the evaporation could be stopped and re-activated without losing alkali metal yield because the metal not yet consumed remains in its stable form. A full characterization of dispensing material, dispenser configuration and dispensing process has been carried out in order to optimize the evaporation and deposition dynamics of alkali metals layers. The study has been performed applying also inside developed simulations tools.

  4. Hydrogen production by high-temperature electrolysis of steam

    International Nuclear Information System (INIS)

    Hydrogen production by high-temperature electrolysis of steam is a reverse process of a solid oxide fuel cell under development in the world. It is a simple and efficient process to produce hydrogen from water theoretically. In JAERI, bench-scale tests using an electrolysis tube have been conducted to investigate electrolysis characteristics and to accumulate operational know-how for a plant with is a utility system of high temperature heat from high temperature gas-cooled reactors. An electrolysis tube was fabricated by connecting 12 electrolysis cells in series. The cell consisted of multi-layers of an electrolyte and electrodes coated on a base ceramic tube. The electrolyte layer was made of yttria-stabilized zirconia. In the test, steam was supplied with argon gas as a carrier gas and DC power to the electrolyte through the electrodes. Hydrogen production rate increased with the applied power and the electrolysis temperature. The maximum production rate was 7.6 NL/h at 950 deg. C and the applied power of 27W. (author). 5 refs, 7 figs, 1 photo

  5. Stray current control in electrolysis plant

    International Nuclear Information System (INIS)

    Stray current can appear in any industrial plant powered by electricity. In electrolysis plants the probability for stray current appearance is high due to the use of electrolytes, which are current-conductive liquid media. Busbars, metallic equipment, electrolyte, the ground and the human body are to a different extent DC current-conductive. Brought in contact in an electrolysis plant, they act as a complex electrical network supplied by a rectifier. As a result, uncontrolled stray currents can flow causing hazard (even electrocution) to the operating personal, power loss and/or damage to the equipment. Despite its major importance for all metal winning and refining electrolysis processes, the stray current issue is very scarcely treated in the published literature. This paper reveals the fundamentals for stray current appearance pointing out to the two major loops in the plant. In the internal loop stray current flows through the electrolyte distribution system causing power loss and hardware damage by stray current induced corrosion. The heat exchanger used for electrolyte preheating is especially critical. The external stray current loop covers stray current cases caused by electrolyte leakage. It impacts on power losses and hazards to the personnel. LUSCURE (LUrgi Stray-CUrrent-cuRE) is a new method for localization, control and reduction of stray current in an electrolysis plant. It involves a translation of the plant and equipment design into an equivalent electrical circuit that is calculated and analysed. LUSCURE was verified by assessing a German copper refinery and by being extensively used in plant and equipment design for the High Current Density Copper Electrowinning Process (HCD). (author)

  6. Hydrogen production through biocatalyzed electrolysis

    OpenAIRE

    Rozendal, R.A.

    2007-01-01

    cum laude graduation (with distinction) To replace fossil fuels, society is currently considering alternative clean fuels for transportation. Hydrogen could be such a fuel. In theory, large amounts of renewable hydrogen can be produced from organic contaminants in wastewater. During his PhD research René Rozendal has developed a new technology for this purpose: biocatalyzed electrolysis. The innovative step of biocatalyzed electrolysis is the application of electrochemically active microorgan...

  7. Milk-alkali syndrome

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000332.htm Milk-alkali syndrome To use the sharing features on this page, please enable JavaScript. Milk-alkali syndrome is a condition in which there ...

  8. Fused salt electrolysis

    International Nuclear Information System (INIS)

    Working conditions for zirconium preparation by fused salt electrolysis were studied. For such purpose, a cell was built for operation under argon atmosphere. A graphite crucible served as anode, with steel cathodes. Proper design allowed cathode rechange under the inert atmosphere. Cathodic deposits of zirconium powder occluded salts from the bath. After washing with both water and hydrochloric acid, the metallic powder was consolidated by fusion. Optimum operating conditions were found to arise from an electrolyte of 12% potassium hexafluorzirconate -88% sodium chloride, at 820 deg C and 5 A/cm2 cathodic current density. Deposits contained 35% of metal and current efficiency reached 66%. The powder contained up to 600 ppm of chlorine and 1.700 ppm of fluorine; after fusion, those amounts decreased to 2 ppm and 3 ppm respectively, with low proportion of metallic impurities. Though oxygen proportion was 4.500 ppm, it should be lowered by improving working conditions, as well as working on an ampler scale. (Author)

  9. Elimination technique for alkali metal ion adducts from an electrospray ionization process using an on-line ion suppressor

    OpenAIRE

    NOZAKI, Kazuyoshi; TARUI, Akira; OSAKA, Issey; Kawasaki, Hideya; ARAKAWA, Ryuichi; 荒川, 隆一

    2010-01-01

    The effects of an on-line ion suppressor device on alkali metal ion adduct formations of the model compound tacrolimus were investigated. The base peak ion in the positive ion ESI-MS spectrum of tacrolimus was a sodium ion adduct, [M+Na]+. On the other hand, an ammonium ion adduct, [M+NH4]+, was the base peak ion in the full-scan mass spectrum of tacrolimus with a cation-exchange suppressor resin, and both [M+Na]+ and [M+K]+ were eliminated. These results indicate that the combination of an o...

  10. Hydrogen production from high temperature electrolysis and fusion reactor

    International Nuclear Information System (INIS)

    Production of hydrogen from high temperature electrolysis of steam coupled with a fusion reactor is studied. The process includes three major components: the fusion reactor, the high temperature electrolyzer and the power conversion cycle each of which is discussed in the paper. Detailed process design and analysis of the system is examined. A parametric study on the effect of process efficiency is presented

  11. Recovery of alkali metal constituents from catalytic coal conversion residues

    Science.gov (United States)

    Soung, W.Y.

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  12. Electrolysis of carbon dioxide in Solid Oxide Electrolysis Cells

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Mogensen, Mogens Bjerg

    2009-01-01

    Carbon dioxide electrolysis was studied in Ni/YSZ electrode supported Solid Oxide Electrolysis Cells (SOECs) consisting of a Ni-YSZ support, a Ni-YSZ electrode layer, a YSZ electrolyte, and a LSM-YSZ O2 electrode (YSZ = Yttria Stabilized Zirconia). The results of this study show that long term CO2...... current density and irreversible when operated at conditions that would oxidise carbon. This clearly shows that the passivation was not caused by coke formation. On the other hand, the passivation was partly reversible when introducing hydrogen. The passivation may be a consequence of impurities in the...

  13. Gadolinia-Doped Ceria Cathodes for Electrolysis of CO2

    Science.gov (United States)

    Adler, Stuart B.

    2009-01-01

    Gadolinia-doped ceria, or GDC, (Gd(0.4)Ce(0.6)O(2-delta), where the value of delta in this material varies, depending on the temperature and oxygen concentration in the atmosphere in which it is being used) has shown promise as a cathode material for high-temperature electrolysis of carbon dioxide in solid oxide electrolysis cells. The polarization resistance of a GDC electrode is significantly less than that of an otherwise equivalent electrode made of any of several other materials that are now in use or under consideration for use as cathodes for reduction of carbon dioxide. In addition, GDC shows no sign of deterioration under typical temperature and gas-mixture operating conditions of a high-temperature electrolyzer. Electrolysis of CO2 is of interest to NASA as a way of generating O2 from the CO2 in the Martian atmosphere. On Earth, a combination of electrolysis of CO2 and electrolysis of H2O might prove useful as a means of generating synthesis gas (syngas) from the exhaust gas of a coal- or natural-gas-fired power plant, thereby reducing the emission of CO2 into the atmosphere. The syngas a mixture of CO and H2 could be used as a raw material in the manufacture, via the Fisher-Tropsch process, of synthetic fuels, lubrication oils, and other hydrocarbon prod

  14. Heavy water production by alkaline water electrolysis

    International Nuclear Information System (INIS)

    Several heavy water isotope production processes are reported in literature. Water electrolysis in combination with catalytic exchange CECE process is considered as a futuristic process to increase the throughput and reduce the cryogenic distillation load but the application is limited due to the high cost of electricity. Any improvement in the efficiency of electrolyzers would make this process more attractive. The efficiency of alkaline water electrolysis is governed by various phenomena such as activation polarization, ohmic polarization and concentration polarization in the cell. A systematic study on the effect of these factors can lead to methods for improving the efficiency of the electrolyzer. A bipolar and compact type arrangement of the alkaline water electrolyzer leads to increased efficiency and reduced inventory in comparison to uni-polar tank type electrolyzers. The bipolar type arrangement is formed when a number of single cells are stacked together. Although a few experimental studies have been reported in the open literature, CFD simulation of a bipolar compact alkaline water electrolyzer with porous electrodes is not readily available.The principal aim of this study is to simulate the characteristics of a single cell compact electrolyzer unit. The simulation can be used to predict the Voltage-Current Density (V-I) characteristics, which is a measure of the efficiency of the process.The model equations were solved using COMSOL multi-physics software. The simulated V-I characteristic is compared with the experimental data

  15. Application of chitosan as flocculant for coprecipitation of Mn(II) and suspended solids from dual-alkali FGD regenerating process.

    Science.gov (United States)

    Wu, Zhong-Biao; Ni, Wei-Min; Guan, Bao-Hong

    2008-04-01

    Heavy metals and suspended solid (SS) needed to be removed from the recirculation of dual-alkali flue gas desulfurization (FGD) system. The feasibility of coprecipitation of heavy metal and SS by water-soluble chitosan was studied in a lab scale experiment. The association between chitosan and metal ions was verified through DSC and FT-IR. The pH investigation revealed that at the pH ranged from 5 to 9, there were three stages for different actions: adsorption of chitosan for Mn(II), precipitation of manganese hydroxide and coprecipitation of manganese hydroxide and chitosan-Mn(II) complex. The ion selectivity experiments showed that the occurrence of Ca(II) in the solution had little influence on the adsorption of chitosan for Mn(II). The decrease rate of adsorption capacity was about 0.0023 mmol g(-1) per 1 mg L(-1) Ca(II). When adsorption and flocculation of chitosan occurred at the same time and at the sufficient addition of chitosan, chitosan not only made solids flocculate but also enhanced sorption capacity of chitosan. Application of chitosan for coprecipitation of Mn(II) and SS could remove Mn(II) efficiently and improve the settling characteristics of SS from dual-alkali FGD regenerating process. PMID:17764834

  16. Development status of a preprototype water electrolysis subsystem

    Science.gov (United States)

    Martin, R. B.; Erickson, A. C.

    1981-01-01

    A preprototype water electrolysis subsystem was designed and fabricated for NASA's advanced regenerative life support program. A solid polymer is used for the cell electrolyte. The electrolysis module has 12 cells that can generate 5.5 kg/day of oxygen for the metabolic requirements of three crewmembers, for cabin leakage, and for the oxygen and hydrogen required for carbon dioxide collection and reduction processes. The subsystem can be operated at a pressure between 276 and 2760 kN/sq m and in a continuous constant-current, cyclic, or standby mode. A microprocessor is used to aid in operating the subsystem. Sensors and controls provide fault detection and automatic shutdown. The results of development, demonstration, and parametric testing are presented. Modifications to enhance operation in an integrated and manned test are described. Prospective improvements for the electrolysis subsystem are discussed.

  17. Corrosion by the Alkali Metals

    International Nuclear Information System (INIS)

    This is a review of the state of the art of corrosion testing of materials by the alkali metals, the models proposed to explain the observed corrosion results, and the status of materials selection for application in alkali metal-cooled systems. Corrosion of structural and fuel cladding materials by liquid Na and NaK has been studied intensively, but intermittently for the last 18 years. These studies and the liquid-metal-cooled reactors in operation demonstrate that stainless steels can be considered for structural and cladding applications below 650°C. Above this temperature increased corrosion and radiation-induced embrittlement make them unsatisfactory. Corrosion models are reviewed and their inability to explain all the experimental observations discussed. An alternate model is proposed which qualitatively is in agreement with experimental observations. In this model, the rate-controlling step is either the surface reaction of Fe with ''available oxygen'' (dissolved Na2O) to form an Fe-O-Na complex or the rate at which ''available oxygen'' can reach the surface to form the complex; which process is rate controlling depends on the temperature, Na velocity and oxygen concentration in the Na. The solution chemistry of oxygen, carbon and alkali metal-oxygen-transition metal complexes dissolved in the alkali metals is reviewed. ''Molecular'' complexes appear unlikely to exist in solution in the alkali metals, although the thermodynamic tendencies for them to form suggest that stable bonds exist in solution between oxygen, the transition and the alkali metals. The insolubility of carbon in ''oxygen-free'' sodium indicates that carbon transfer may be associated with oxygen in sodium down to very low oxygen levels, although experimental data do not generally confirm this postulate. Corrosion of refractory metals by boiling alkali metals at temperatures above 1000°C is markedly affected by impurities in either the liquid or refractory metal; the addition of Ti, Zr or

  18. Treatment of Pharmaceutical Wastewater by Catalyzed Internal Electrolysis/ Hydrolysis Acidification/Bio-contact Oxidation/Coagulation Process%催化内电解/水解/接触氧化/混凝法处理制药废水

    Institute of Scientific and Technical Information of China (English)

    潘碌亭; 王文蕾; 余波

    2013-01-01

    The catalyzed internal electrolysis/hydrolysis acidification/bio-contact oxidation/coagulation process was used for the treatment of pharmaceutical wastewater. The COD removal rate was 61% while the B/C improved from 0. 1 to above 0. 3 after the catalyzed internal electrolysis. The system had high resistance to influent loads, and the removal rates of COD, NH3 -N and TP were 89% , 95% and nearly 100% , respectively. The effluent quality met the first class criteria specified in the Integrated Wastewater Discharge Standard (GB 8978 - 1996). The operation cost of the combined process was only 1. 61 yuan/m3.%采用催化内电解/水解酸化/接触氧化/混凝工艺处理制药废水.经催化内电解预处理后,对COD的去除率达61%,B/C值由0.1上升到0.3以上;系统对进水水质有良好的抗冲击性能,且对COD、NH3-N的平均去除率分别为89%、95%,对TP几乎能全部去除,出水水质达到《污水综合排放标准》(GB 8978-1996)的一级标准;该工艺处理费用仅为1.61元/m3.

  19. 2nd Generation Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Yde, Lars; Kjartansdóttir, Cecilia Kristin; Allebrod, Frank; Mogensen, Mogens Bjerg; Møller, Per; Hilbert, Lisbeth R.; Nielsen, Peter Tommy; Mathiesen, Troels; Jensen, Jørgen; Andersen, Lars; Dierking, Alexander

    This report provides the results of the 2nd Generation Alkaline Electrolysis project which was initiated in 2008. The project has been conducted from 2009-2012 by a consortium comprising Århus University Business and Social Science – Centre for Energy Technologies (CET (former HIRC)), Technical...

  20. PEM Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Hansen, Martin Kalmar

    needed and hence it has become acute to be able to store the energy. Hydrogen has been identified as a suitable energy carrier and water electrolysis is one way to produce it in a sustainable and environmentally friendly way. In this thesis an introduction to the subject (chapter 1) is given followed by...... a literature review of the field of water electrolysis (chapter 2), with a focus on proton exchange membrane (PEM) electrolysis. In chapter 3 a short description of the experimental techniques used for synthesis of catalyst and characterisation of the components in the electrolysis cell is given....... This is followed in chapter 4 by a description of the electrolysis setups and electrolysis cells used during the work. Two different setups were used, one operating at atmospheric pressure and another that could operate at elevated pressure so that liquid water electrolysis could be performed at...

  1. Hydrogen production test by high temperature electrolysis of steam. Test results with self-supporting planar cell

    International Nuclear Information System (INIS)

    Hydrogen production process by high-temperature electrolysis of steam is expected to be one of hydrogen production processes suitable for high-temperature gas-cooled reactors. A self-supporting planar electrolysis cell was fabricated: the electrolyte of the cell was made from a thin plate of yttria-stabilized zirconia with 0.3 mm in thickness, and an electrode film layered on the plate had an area of 64 cm2. In the electrolysis test conducted at an electrolysis temperature of 850degC, hydrogen was produced at a rate of 2.4 Nl/h. Test results showed that the planar cell had a better hydrogen production performance than the electrolysis tube with 12 cells tested before. This report presents an outline of planar cell, test results, and problems obtained through the electrolysis test. (author)

  2. Electrolysis of carbon dioxide for carbon monoxide production in a tubular solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    Highlights: • An experimental study for the CO regeneration was demonstrated. • Higher current densities at higher temperatures were obtained. • The scale of the combined system was estimated experimentally at 800 °C. • The required surface area of the cells was estimated to be 65.6 km2/BF unit. • The combined system may contribute to establishing a low-carbon society. - Abstract: An active carbon recycling energy system (ACRES) based on carbon recycling has been proposed as a new energy transformation system. This energy transformation system reduces the carbon dioxide (CO2) emissions in the atmosphere during the iron-making process. An experimental study for electrochemical CO production by CO2 electrolysis based on the ACRES concept was carried out using a tubular solid oxide electrolysis cell. Experimental results show that the CO and oxygen (O2) production rates at 800, 850, and 900 °C were almost proportional to the current passing through the cell. Both ionic conductivity and the chemical kinetics of CO2 decomposition increased with increasing temperature. The highest current density and CO production rate at 900 °C were 2.97 mA/cm2 and 0.78 μmol/(min cm2), respectively. On the basis of the electrolytic characteristics of the cell, the scale of the combined ACRES CO2 electrolysis/iron-making system was estimated

  3. Microbial electrolysis desalination and chemical-production cell for CO2 sequestration

    KAUST Repository

    Zhu, Xiuping

    2014-05-01

    Mineral carbonation can be used for CO2 sequestration, but the reaction rate is slow. In order to accelerate mineral carbonation, acid generated in a microbial electrolysis desalination and chemical-production cell (MEDCC) was examined to dissolve natural minerals rich in magnesium/calcium silicates (serpentine), and the alkali generated by the same process was used to absorb CO2 and precipitate magnesium/calcium carbonates. The concentrations of Mg2+ and Ca2+ dissolved from serpentine increased 20 and 145 times by using the acid solution. Under optimal conditions, 24mg of CO2 was absorbed into the alkaline solution and 13mg of CO2 was precipitated as magnesium/calcium carbonates over a fed-batch cycle (24h). Additionally, the MEDCC removed 94% of the COD (initially 822mg/L) and achieved 22% desalination (initially 35g/L NaCl). These results demonstrate the viability of this process for effective CO2 sequestration using renewable organic matter and natural minerals. © 2014 Elsevier Ltd.

  4. Treatment of Pharmaceutical Wastewater by Electrolysis/Hydrolysis Acidification/Aerobic Activated Sludge Process%电解/水解酸化/活性污泥法处理医药废水研究

    Institute of Scientific and Technical Information of China (English)

    杨宗政; 宋健; 庞金钊

    2009-01-01

    采用电解/水解酸化/好氧活性污泥工艺处理高浓度、难降解的医药生产废水,着重考察了HRT、温度、pH、溶解氧及污泥负荷对好氧段处理效果的影响.结果表明,电解/水解酸化提高了废水的可生化性,在HRT为18 h、温度为24℃、pH值为6.5~7.0、溶解氧为2.5 mg/L以及污泥负荷为0.42~0.50 kgCOD/(kgMLSS·d)的条件下,好氧段对COD的去除效果较好,去除率基本稳定在90%左右,出水水质满足(GB 8978-1996)的二级标准.%Electrolysis/hydrolysis acidification/aerobic activated sludge process was used for treat-ment of high strength and refractory wastewater from pharmaceutical industry. The influence factors such as HRT, temperature, pH, DO and sludge load on treatment effect at aerobic stage were investigated. The results show that the electrolysis and hydrolysis acidification improve the wastewater biodegradability. The good COD removal effect can be obtained when HRT is 18 h, temperature is 24℃, pH is 6.5 to rate of 90%. The effluent quality meets the second level criteria specified in Integrated Wastewater Dis-charge Standard (GB 8978 - 1996).

  5. Solid oxide electrolysis cells - Performance and durability

    Energy Technology Data Exchange (ETDEWEB)

    Hauch, A.

    2007-10-15

    In this work H2 electrode supported solid oxide cells (SOC) produced at Risoe National Laboratory, DTU, have been used for steam electrolysis. Electrolysis tests have been performed at temperatures from 650AeC to 950AeC, p(H2O)/p(H2) from 0.99/0.01 to 0.30/0.70 and current densities from -0.25 A/cm2 to -2 A/cm2. The solid oxide electrolysis cells (SOEC) have been characterised by iV curves and electrochemical impedance spectroscopy (EIS) at start and end of tests and by EIS under current load during electrolysis testing. The tested SOCs have shown the best initial electrolysis performance reported in literature to date. Area specific resistances of 0.26 Oecm2 at 850AeC and 0.17 Oecm2 at 950AeC were obtained from electrolysis iV curves. The general trend for the SOEC tests was: 1) a short-term passivation in first few hundred hours, 2) then an activation and 3) a subsequent and underlying long-term degradation. The transient phenomenon (passivation/activation) was shown to be a set-up dependent artefact caused by the albite glass sealing with a p(Si(OH)4) of 1.10-7 atm, leading to silica contamination of the triple-phase boundaries (TPBs) of the electrode. The long-term degradation for the SOECs was more pronounced than for fuel cell testing of similar cells. Long-term degradation of 2%/1000 h was obtained at 850AeC, p(H2O)/p(H2) = 0.5/0.5 and -0.5 A/cm2, whereas the degradation rate increased to 6%/1000h at 950AeC, p(H2O)/p(H2) = 0.9/0.1 and -1.0 A/cm2. Both the short-term passivation and the long-term degradation appear mainly to be related to processes in the H2 electrode. Scanning electron microscopy micrographs show that only limited changes occur in the Ni particle size distribution and these are not the main degradation mechanism for the SOECs. Micro and nano analysis using energy dispersive spectroscopy in combination with transmission electron microscopy (TEM) and scanning TEM reveals that glassy phase impurities have accumulated at the TPBs as a result of

  6. Principle and perspectives of hydrogen production through biocatalyzed electrolysis

    NARCIS (Netherlands)

    Rozendal, R.A.; Hamelers, H.V.M.; Euverink, G.J.W.; Metz, S.J.; Buisman, C.J.N.

    2006-01-01

    Biocatalyzed electrolysis is a novel biological hydrogen production process with the potential to efficiently convert a wide range of dissolved organic materials in wastewaters. Even substrates formerly regarded to be unsuitable for hydrogen production due to the endothermic nature of the involved c

  7. High temperature electrolysis for hydrogen production using nuclear energy

    International Nuclear Information System (INIS)

    High-temperature nuclear reactors have the potential for substantially increasing the efficiency of hydrogen production from water splitting, which can be accomplished via high-temperature electrolysis (HTE) or thermochemical processes. In order to achieve competitive efficiencies, both processes require high-temperature operation (∼850degC). High-temperature electrolytic water splitting supported by nuclear process heat and electricity has the potential to produce hydrogen with overall system efficiencies of 45 to 55%. At the Idaho National Laboratory, we are developing solid-oxide cells to operate in the steam electrolysis mode. The research program includes both experimental and modeling activities. Experimental results were obtained from ten-cell and 22-cell planar electrolysis stacks, fabricated by Ceramatec, Inc. The electrolysis cells are electrolyte-supported, with scandia-stabilized zirconia electrolytes (∼200 μm thick, 64 cm2 active area), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions, gas glow rates, and current densities. Hydrogen production rates greater than 100 normal liters per hour for 196 hours have been demonstrated. In order to evaluate the performance of large-scale HTE operations, we have developed single-cell models, based on FLUENT, and a process model, using the systems-analysis code HYSYS. (author)

  8. Novel homogeneous anion-selective membranes for alkaline water electrolysis

    Czech Academy of Sciences Publication Activity Database

    Hnát, J.; Schauer, Jan; Paidar, M.; Bouzek, K.

    Praha : Orgit, 2012. s. 116-117. ISBN 978-80-905035-2-6. [Electromembrane Processes and Materials - ELMEMPRO 2012, Satellite Meeting of The International Society of Electrochemistry Annual Meeting /63./. 26.08.2012-29.08.2012, Český Krumlov] Institutional support: RVO:61389013 Keywords : membranes * water electrolysis Subject RIV: CD - Macromolecular Chemistry

  9. Water Electrolysis for In-Situ Resource Utilization (ISRU)

    Science.gov (United States)

    Lee, Kristopher A.

    2016-01-01

    Sending humans to Mars for any significant amount of time will require capabilities and technologies that enable Earth independence. To move towards this independence, the resources found on Mars must be utilized to produce the items needed to sustain humans away from Earth. To accomplish this task, NASA is studying In Situ Resource Utilization (ISRU) systems and techniques to make use of the atmospheric carbon dioxide and the water found on Mars. Among other things, these substances can be harvested and processed to make oxygen and methane. Oxygen is essential, not only for sustaining the lives of the crew on Mars, but also as the oxidizer for an oxygen-methane propulsion system that could be utilized on a Mars ascent vehicle. Given the presence of water on Mars, the electrolysis of water is a common technique to produce the desired oxygen. Towards this goal, NASA designed and developed a Proton Exchange Membrane (PEM) water electrolysis system, which was originally slated to produce oxygen for propulsion and fuel cell use in the Mars Atmosphere and Regolith COllector/PrOcessor for Lander Operations (MARCO POLO) project. As part of the Human Exploration Spacecraft Testbed for Integration and Advancement (HESTIA) project, this same electrolysis system, originally targeted at enabling in situ propulsion and power, operated in a life-support scenario. During HESTIA testing at Johnson Space Center, the electrolysis system supplied oxygen to a chamber simulating a habitat housing four crewmembers. Inside the chamber, oxygen was removed from the atmosphere to simulate consumption by the crew, and the electrolysis system's oxygen was added to replenish it. The electrolysis system operated nominally throughout the duration of the HESTIA test campaign, and the oxygen levels in the life support chamber were maintained at the desired levels.

  10. Technoeconomic analysis of a methanol plant Based on gasification of biomass and Electrolysis of water

    OpenAIRE

    Clausen, Lasse R.; Houbak, Niels; Elmegaard, Brian

    2010-01-01

    Abstract Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2 from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enab...

  11. Fundamentals of SO2 depolarized water electrolysis and challenges of materials used

    OpenAIRE

    Lokkiluoto, Anu

    2013-01-01

    Sulfur dioxide depolarized water electrolysis (SDE) produces sulfuric acid and hydrogen. Due to its lower cell voltage, the process requires far less electricity than traditional water electrolysis. When SO2 is obtained from flash smelting, sulfides roasting, sulfur combustion, or any other similar operation, SDE is a part of the OutotecR open cycle process. In the present work, materials to be used in SDE were studied together with the fundamentals of the process. Data on the co-productio...

  12. Desulfurization from Bauxite Water Slurry (BWS) Electrolysis

    Science.gov (United States)

    Gong, Xuzhong; Ge, Lan; Wang, Zhi; Zhuang, Siyuan; Wang, Yuhua; Ren, Lihui; Wang, Mingyong

    2016-02-01

    Feasibility of high-sulfur bauxite electrolysis desulfurization was examined using the electrochemical characterization, XRD, DTA, and FTIR. The cyclic voltammetry curves indicated that bauxite water slurry (BWS) electrolysis in NaOH system was controlled by diffusion. Additionally, the desulfurization effect of NaCl as the electrolyte was significantly better than that of NaOH as an electrolyte. As the stirring rate increased, the desulfurization ratio in NaCl system was not increased obviously, while the desulfurization ratio in NaOH system increased significantly, indicating further that electrolysis desulfurization in NaOH solution was controlled by diffusion. According to XRD, DTA, and FTIR analysis, the characteristic peaks of sulfur-containing phase in bauxite after electrolysis weakened or disappeared, indicating that the pyrite in bauxite was removed from electrolysis. Finally, the electrolytic desulfurization technology of bauxite was proposed based on the characteristics of BWS electrolysis.

  13. Study on hydrogen production by high temperature electrolysis of steam

    International Nuclear Information System (INIS)

    In JAERI, design and R and D works on hydrogen production process have been conducted for connecting to the HTTR under construction at the Oarai Research Establishment of JAERI as a nuclear heat utilization system. As for a hydrogen production process by high-temperature electrolysis of steam, laboratory-scale experiments were carried out with a practical electrolysis tube with 12 cells connected in series. Hydrogen was produced at a maximum density of 44 Nml/cm2h at 950degC, and know-how of operational procedures and operational experience were also accumulated. Thereafter, a planar electrolysis cell supported by a metallic plate was fabricated in order to improve hydrogen production performance and durability against thermal cycles. In the preliminary test with the planar cell, hydrogen has been produced continuously at a maximum density of 33.6 Nml/cm2h at an electrolysis temperature of 950degC. This report presents typical test results mentioned above, a review of previous studies conducted in the world and R and D items required for connecting to the HTTR. (author)

  14. Combined electrical-alkali pretreatment to increase the anaerobic hydrolysis rate of waste activated sludge during anaerobic digestion

    International Nuclear Information System (INIS)

    Highlights: • Combined electrical-alkali pretreatment for improving sludge anaerobic digestion was proposed. • Combined process enhanced the cell lysis, biopolymers releases, and thus sludge disintegration. • Increased solubilization of sludge increased the anaerobic hydrolysis rate. • Increased solubilization does not always induce an improved anaerobic digestion efficiency. - Abstract: Pretreatment can be used prior to anaerobic digestion to improve the efficiency of waste activated sludge (WAS) digestion. In this study, electrolysis and a commonly used pretreatment method of alkaline (NaOH) solubilization were integrated as a pretreatment method for promoting WAS anaerobic digestion. Pretreatment effectiveness of combined process were investigated in terms of disintegration degree (DDSCOD), suspended solids (TSS and VSS) removals, the releases of protein (PN) and polysaccharide (PS), and subsequent anaerobic digestion as well as dewaterability after digestion. Electrolysis was able to crack the microbial cells trapped in sludge gels and release the biopolymers (PN and PS) due to the cooperation of alkaline solubilization, enhancing the sludge floc disintegration/solubilization, which was confirmed by scanning electron microscopy (SEM) analysis. Biochemical methane potential (BMP) assays showed the highest methane yield was achieved with 5 V plus pH 9.2 pretreatment with up to 20.3% improvement over the non-pretreated sludge after 42 days of mesophilic operation. In contrast, no discernible improvements on anaerobic degradability were observed for the rest of pretreated sludges, probably due to the overmuch leakage of refractory soluble organics, partial chemical mineralization of solubilized compounds and sodium inhibition. The statistical analysis further indicated that increased solubilization induced by electrical-alkali pretreatment increased the first-order anaerobic hydrolysis rate (khyd), but had no, or very slight enhancement on WAS ultimate

  15. Theoretical modeling of NO electrochemical reduction on multifunctional layer electrode by alternating/direct current electrolysis

    International Nuclear Information System (INIS)

    Highlights: • Mechanistic modeling of nitrogen oxide electrochemical reduction. • Fundamentals of both alternative and direct current electrolysis. • Theoretical optimal frequency in alternative current electrolysis. - Abstract: A one-dimensional symmetric model on NO electrochemical reduction in solid oxide electrolysis cell(SOEC) considering gas transport, electronic conduction, ionic conduction, and electrochemical process based on multifunctional layer electrode is developed. The simulation results agree well with the experimental results both in the direct current(DC) and alternative current(AC) electrolysis. The distributions of the NO concentration in the electrode are predicted in both DC and AC electrolysis. The effects of temperature, voltage, and O2 concentration were investigated on NO alternative current electrolysis and direct current electrolysis processes. The modeling results show that the optimal frequency of 0.3 Hz is corresponded to the maximum NO decomposition rate in different temperatures and voltages. The NO decomposition increases with increasing temperature and decreasing O2 concentration in most cases. At 450 °C, the NO decomposition presents first increased and then decreased trend with different voltages at the frequency of 0.3 Hz. This is similar to the effects of O2 concentration at 450 °C and 475 °C at the same frequency

  16. Durability of Solid Oxide Electrolysis Cell and Interconnects for Steam Electrolysis

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hendriksen, Peter Vang; Mogensen, Mogens Bjerg

    2013-01-01

    Durability of a solid oxide electrolysis cell tested at -1.5A / cm2 for high temperature steam electrolysis was investigated in the present work under stack relevant conditions. Detailed electrochemical and microstructural analyses were carried out. The results show that both the hydrogen and the...... interconnects on cell degradation under harsh electrolysis conditions is further discussed....

  17. The Alkali/Surfactant/ Polymer Process: Effects of Slug Size, Core Length and a Chase Polymer Le procédé alkali/surfactant/polymère : effets de la taille du bouchon, de la longueur de la carotte et d'un polymère de déplacement

    OpenAIRE

    Green K. A.; Nasr-El-Din H. A.; Schramm L. L.

    2006-01-01

    An experimental study was conducted to examine the effects of slug size, core length, and a chase polymer on the effectiveness of the alkali/surfactant/polymer (A/S/P) process in recovering waterflood residual oil. Core flood experiments were conducted with unfired linear Berea sandstone cores. The tertiary oil recovery, oil cut, pressure drop, and chemical propagation were measured for each flood. Tertiary oil recovery significantly increased with the slug size up to 0. 5 of a pore volume. I...

  18. Transient nanobubbles in short-time electrolysis

    Science.gov (United States)

    Svetovoy, Vitaly B.; Sanders, Remco G. P.; Elwenspoek, Miko C.

    2013-05-01

    Water electrolysis in a microsystem is observed and analyzed on a short-time scale of ∼10 μs. The very unusual properties of the process are stressed. An extremely high current density is observed because the process is not limited by the diffusion of electroactive species. The high current is accompanied by a high relative supersaturation, S > 1000, that results in homogeneous nucleation of bubbles. On the short-time scale only nanobubbles can be formed. These nanobubbles densely cover the electrodes and aggregate at a later time to microbubbles. The effect is significantly intensified with a small increase of temperature. Application of alternating polarity voltage pulses produces bubbles containing a mixture of hydrogen and oxygen. Spontaneous reaction between gases is observed for stoichiometric bubbles with sizes smaller than ∼150 nm. Such bubbles disintegrate violently affecting the surfaces of the electrodes.

  19. Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    金一中; 张月锋; 李伟

    2002-01-01

    Experiments were conducted to study the role of micro-electrolysis i n removing chromaticity and COD and improving the biodegradability of pharmaceuti cal wastewater. The results showed that the use of micro-electrolysis technolog y could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH co uld be advantageous to the removal of chromaticity. A retention time of 30 minut es was recommended for the process design of micro-electrolysis.

  20. Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    金一中; 张月锋; 李伟

    2002-01-01

    Experiments were conducted to study the role of micro-electrolysis in removng chromaticity and COD and improving the biodegradability of pharmaceutical wastewater.The results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of phamaceutical wastewater.Lower initial pH could be advantageous to the removal of chromaticity .A retention time of 30 minutes was recommended for the process design of micro-electrolysis.

  1. Life cycle assessment of high temperature electrolysis for hydrogen production via nuclear energy

    International Nuclear Information System (INIS)

    A life cycle assessment (LCA) of one proposed method of hydrogen production - the high temperature electrolysis of water vapor - is presented in this paper. High temperature electrolysis offers an advantage of higher energy efficiency over the conventional low-temperature alkaline electrolysis due to reduced cell potential and consequent electrical energy requirements. The primary energy source for the electrolysis will be advanced nuclear reactors operating at temperatures corresponding to those required for the high temperature electrolysis. The LCA examines the environmental impact of the combined advanced nuclear-high temperature electrolysis plant, focusing upon quantifying the emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides per kilogram of hydrogen produced. The results are presented in terms of the global warming potential (GWP) and the acidification potential (AP) of the system. The GWP for the system is 2000g carbon dioxide equivalent and the AP, 0.15g equivalents of hydrogen ion equivalent per kilogram of hydrogen produced. The GWP and AP of this process are one-sixth and one-third, respectively, of those for the hydrogen production by steam reforming of natural gas, and are comparable to producing hydrogen from wind- or hydro-electricity powered conventional electrolysis. (author)

  2. Deep Treatment of Papermaking Wastewater with Micro-Electrolysis Process Based on Hydrogen Peroxide and Oxygen%添加H2O2/O2的微电解深度处理造纸中段废水

    Institute of Scientific and Technical Information of China (English)

    刘春; 管秀琼; 胥霞林; 王毅

    2011-01-01

    In the conditions of pH 4.5, iron/carbon 1:1, reaction time 40 min, hydrogen peroxide 0.5 mg·L^- 1 wastewater, one oxygen with micro-electrolysis process which was enhanced by hydrogen peroxide and oxygen. e results showed that COD Cr is about 51 mg·L^- 1 and the chromaticity is about 48 times, which up to the newly national papermaking wastewater standard. It was also indicated that the process is fit for pretreatment or deep treatment.%在废水传统微电解处理工艺的基础上,增加了H2O2/O2处理,实验结果表明:在pH值4.5,Fe/C=1:1,反应时间40min,H2O2加入量0.8mg·L^-1废水,曝气头1个的条件下,H2O2/O2对传统微电解工艺具有加强作用,出水色度48倍,CODCr为51mg·L^-1,达到最新造纸行业废水排放标准。且该工艺较适合作为二级生化前的预处理或后处理工艺。

  3. THE DIGESTION OPERATION IN THE ALKALI ALUMINAT SOLUTIONS OF ALUMINUM HYDROXIDES IN THE BOEHMITIC BAUXITES

    Directory of Open Access Journals (Sweden)

    Sami ŞAHİN

    1999-01-01

    Full Text Available At present more than 90 per cent of the world's alumina is produced by the Bayer process, a simple technology providing high purity final product. A part from some exceptional local conditions, bauxite is processed almost solely by this technology. As a benefication process, alumina production releases the aluminum oxide content of bauxite from other accompanying oxides thus providing alumina suitable for electrolysis in a cryolite melt. The basic theory of the Bayer process was elaborated by K.J. Bayer and described in his patents in 1887 and 1892. The first patent refers to the aid of seed crystals of aluminum hydroxide or of carbonic acid, that is, to the precipitation and carbonation processes. The second patent formulates the concept that the aluminum oxide content of bauxites can be dissolved in sodium hydroxide solutions, with the formulation of sodium aluminate, a process called digestion nowadays. The most important operations of the Bayer technology are bauxite preparation, crushing, grinding, digestion, red mud separation, thickening, washing, filtration, precipitation, calcination and evaporation. In spite of its great significance as regards the complete Bayer technology, the structure of sodium aluminate solutions has not been cleared up definitely yet. Boehmite is the most important aluminum mineral of karstic bauxites. Some experimental results showing the various effects on aluminum hydroxides by alkali process from boehmitic bauxites and the factors gowerning the digestion operation of aluminate solutions were investigated.

  4. Comparison of process configurations for ethanol production from acid- and alkali-pretreated corncob by Saccharomyces cerevisiae strains with and without β-glucosidase expression.

    Science.gov (United States)

    Wang, Guoqiang; Liu, Cheng; Hong, Jiefang; Ma, Yuanyuan; Zhang, Kun; Huang, Xinyu; Zou, Shaolan; Zhang, Minhua

    2013-08-01

    β-Glucosidase was shown to have synergistic effects with commercial cellulase in the hydrolysis of acid- and alkali-pretreated corncob, especially at the dose of 5 U/g biomass and 5 or 10 FPU/g biomass. An integrating yeast strain 45# expressing β-glucosidase was constructed that utilized cellobiose quickly and efficiently. Process configurations were compared under conditions of 10% solid content, 10 FPU cellulase/g biomass, 5 U β-glucosidase/g biomass (only used for parental strain W303-1A), 1g/kg yeast loading and 3.3g/kg urea supplementation. While separate hydrolysis and fermentation was optimal for W303-1A and the ethanol titer and yield reached 3.22 g/100g and 75.6% (expressed as a percentage of the theoretical yield), respectively, simultaneous saccharification and fermentation was optimal for strain 45# and the ethanol titer and yield reached 3.31 g/100g and 77.7%, respectively. These results are valuable in optimization of the process configuration and improving the yeast strain selected for cellulosic ethanol production. PMID:23735797

  5. Alkali metal ionization detector

    Science.gov (United States)

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  6. 微电解-生物膜复合工艺净化含重金属离子的有机废水%Purification of Organic Wastewater Containing Cu2+ and Cr3+ by a Combined Process of Micro Electrolysis and Biofilm

    Institute of Scientific and Technical Information of China (English)

    李天成; 姜斌; 冯霞; 王大为; 袁绍军; 李鑫钢

    2003-01-01

    A complex process of micro electrolysis and biofilm was developed to continuously treat organic wastewaters containing heavy metal ions such as Cu2+ and Cr3+, and the relevant purifying mechanism was also addressed. In detail, organic materials in wastewater could be consumed as nutritious source by biofilm composed of aerobes and anaerobes. However, for heavy metal ions (Cu2+, Cr3+), part was removed by electrodeposition, and some was adsorbed on biofilm. In order to compare with the combined process of micro electrolysis and biofilm, the experimental data of micro electrolysis process (intermittent) or biofilm process (continuous) were provided, and the kinetic data of C6H12O6 (glucose) biodegradation by cultured microbes or acclimated microbes were also obtained. These experimental results indicated that for wastewater initially consisted of C6H12O6 (500mg. L-1), Cu2+ and Cr3+ (10mg. L-1), after treatment, its concentrations of C6H12O6, Cu2+ and Cr3+ were lowered to the level of 55-65 mg.L-1, and less than 1 mg.L-1, respectively. And the industrial reused water standards could be met by treated wastewater.

  7. Alkaline Electrolysis Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    RIchard Bourgeois; Steven Sanborn; Eliot Assimakopoulos

    2006-07-13

    In this project, GE developed electrolyzer stack technologies to meet DOE’s goals for low cost electrolysis hydrogen. The main barrier to meeting the targets for electrolyzer cost was in stack assembly and construction. GE’s invention of a single piece or “monolithic” plastic electrolyzer stack reduces these costs considerably. In addition, GE developed low cost cell electrodes using a novel application of metal spray coating technology. Bench scale stack testing and cost modeling indicates that the DOE targets for stack capital cost and efficiency can be met by full-scale production of industrial electrolyzers incorporating GE’s stack technology innovations.

  8. Effect of Substrate Concentration to Anode Chamber Performance in Microbial Electrolysis Cell

    OpenAIRE

    Libertus Darus

    2015-01-01

    Microbial electrolysis is a promising process for bio-hydrogen production which might be implemented in waste water treatment in a near future. Unfortunately substrate could be converted into methane by acetoclastic methanogens and will reduce the coulombic efficiency (CE). The research objective was to study the competition between electrogens and methanogens for substrate in a continuous Microbial Electrolysis Cell (MEC).The competition was studied in relation to controlling acetate influen...

  9. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  10. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Science.gov (United States)

    Saksono, Nelson; Febiyanti, Irine Ayu; Utami, Nissa; Ibrahim

    2015-12-01

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  11. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    International Nuclear Information System (INIS)

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H2O2 amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode

  12. Natural gas anodes for aluminium electrolysis in molten fluorides.

    Science.gov (United States)

    Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

    2016-08-15

    Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process. PMID:27210046

  13. HYFIRE: a tokamak-high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 14000C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 7000 to 8000C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constituents, H2 and O2, electrical input is required. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  14. HYFIRE: a tokamak-high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 14000C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 7000 to 8000C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constituents, H2 and O2, electrical input is required. Fourteen hundred degree steam coupled with 40% power efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  15. Hydroxyl radical production in plasma electrolysis with KOH electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Saksono, Nelson; Febiyanti, Irine Ayu, E-mail: irine.ayu41@ui.ac.id; Utami, Nissa; Ibrahim [Department of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia Phone: +62217863516, Fax: +62217863515 (Indonesia)

    2015-12-29

    Plasma electrolysis is an effective technology for producing hydroxyl radical (•OH). This method can be used for waste degradation process. This study was conducted to obtain the influence of applied voltage, electrolyte concentration, and anode depth in the plasma electrolysis system for producing hydroxyl radical. The materials of anode and cathode, respectively, were made from tungsten and stainless steel. KOH solution was used as the solution. Determination of hydroxyl radical production was done by measuring H{sub 2}O{sub 2} amount formed in plasma system using an iodometric titration method, while the electrical energy consumed was obtained by measuring the electrical current throughout the process. The highest hydroxyl radical production was 3.51 mmol reached with 237 kJ energy consumption in the power supply voltage 600 V, 0.02 M KOH, and 0.5 cm depth of anode.

  16. Direct Lit Electrolysis In A Metallic Lithium Fusion Blanket

    Energy Technology Data Exchange (ETDEWEB)

    Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Babineau, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Elvington, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Teprovich, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Vaquer, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-13

    A process that simplifies the extraction of tritium from molten lithium based breeding blankets was developed.  The process is based on the direct electrolysis of lithium tritide using a ceramic Li ion conductor that replaces the molten salt extraction step. Extraction of tritium in the form of lithium tritide in the blankets/targets of fission/fusion reactors is critical in order to maintained low concentrations.  This is needed to decrease the potential tritium permeation to the surroundings and large releases from unforeseen accident scenarios. Because of the high affinity of tritium for the blanket, extraction is complicated at the required low levels. This work identified, developed and tested the use of ceramic lithium ion conductors capable of recovering the hydrogen and deuterium thru an electrolysis step at high temperatures. 

  17. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process

    OpenAIRE

    Grübel, Klaudiusz; Suschka, Jan

    2014-01-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (...

  18. Electrolysis of plutonium in neutral and basic solutions

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    Experiments were conducted on electrolysis of Pu in waste streams. Removal of Pu by this process is maximum at pH 11. Runs on an actual waste stream showed that: Pu can be electrolyzed from neutral or basic solutions down to 10/sup -10/ g/l. Am can also be removed. The removal efficiency is pH dependent. The deposits can be removed by acid leaching. (DLC)

  19. Investigation of Coliform Removal from Drinking Water by Electrolysis

    OpenAIRE

    Rahmani, A; M.R Samarghandi

    2008-01-01

    Introduction & Objective: The practice of eliminating pathogenic microorganisms in water dates back to ancient times. The most common methods for water disinfection are using chemicals, Ozonation, Ultra Violet ray, Membrane Processes and etc. There has been considerable interest in disinfection of water by using electrochemical methods in recent years. The main purpose of this study is to conduct experimental investigation of water disinfection by using the electrolysis method. Inactivation a...

  20. Precision measurements of cross sections of inelastic processes realized in collisions of alkali metal ions with atoms of rare gases

    CERN Document Server

    Lomsadze, R A; Mosulishvili, N O; Kezerashvili, R Ya

    2015-01-01

    This work presents a multifaceted experimental study of collisions of Na$^{+}$ and K$^{+}$ ions in the energy range 0.5 -- 10 keV with He and Ar atoms. Absolute cross sections for charge-exchange, ionization, stripping and excitation were measured using a refined version of the transfer electric field method, angle- and energy-dependent collection of product ions, energy loss, and optical spectroscopy. The experimental data and the schematic correlation diagrams have been employed to analyze and determine the mechanisms for these processes.

  1. Alkalis and Skin.

    Science.gov (United States)

    Greenwood, John E; Tan, Jin Lin; Ming, Justin Choong Tzen; Abell, Andrew D

    2016-01-01

    The aim of this editorial is to provide an overview of the chemical interactions occurring in the skin of our patients on contact with alkaline agents. Strongly basic alkali is highly aggressive and will readily hydrolyze (or cleave) key biological molecules such as lipids and proteins. This phenomenon is known as saponification in the case of lipids and liquefactive denaturation for peptides and proteins. A short section on current first-aid concepts is included. A better understanding of the basic science behind alkali burns will make us better teachers and provide an insight into the urgency needed in treating these common and dangerous chemical injuries. PMID:26182072

  2. Effect of zirconium and niobium on process of uranium dioxide cathodic deposition in molten alkali metal chlorides

    International Nuclear Information System (INIS)

    The process of electrocrystallization of uranium dioxide from molten chloride electrolytes in the presence of tetravalent and pentavalent niobium has been studied by voltammetric method. it has been ascertained that tetravalent zirconium interacts according o exchange mechanism with uranium dioxide with formation of solid solutions (1-x)UO2·xZrO2. Pentavalent niobium is reduced to tetravalent one on the cathode with formation of solid solution (1-y)UO2·NbO2. In simultaneous presence in electrolyte of Zr(4) and Nb(5) ternary solid solutions (1-y-x)UO2·xZrO2·NbO2 are formed on the cathode. 12 refs., 4 figs

  3. Nonradiative DKR processes: revisiting the theory. IV. On the controversy over a polaron state bound to an F center in alkali halides

    OpenAIRE

    Georgiev, Mladen

    2007-01-01

    We are commenting on an earlier hypothesis of polaron states bound to F centers in alkali halides. These states increasing the effective size of the color centers, they play an active role in concentration-dependent phenomena, such as the observed quenching of F center luminescence. Our record shows only one related study on NaBr and NaI which has also been aimed at checking the bound polaron hypothesis. Further studies of the concentration quenching in other alkali halide hosts whould eventu...

  4. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    OpenAIRE

    Márcia de Mello Luvielmo; Caroline Dellinghausen Borges; Daniela de Oliveira Toyama; Claire Tondo Vendruscolo; Adilma Regina Pippa Scamparini

    2016-01-01

    Abstract The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on g...

  5. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

    Science.gov (United States)

    Grübel, Klaudiusz; Suschka, Jan

    2015-05-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

  6. Methods of recovering alkali metals

    Science.gov (United States)

    Krumhansl, James L; Rigali, Mark J

    2014-03-04

    Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

  7. Water electrolysis for hydrogen production in Brazilian perspective

    Energy Technology Data Exchange (ETDEWEB)

    Saliba-Silva, Adonis Marcelo; Carvalho, Fatima M.S.; Bergamaschi, Vanderlei Sergio; Linardi, Marcelo [Instituto de Pesquisas Energeticas e Nucleares (CCCH/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Fuel Cell and Hydrogen Center], Email: saliba@ipen.br

    2009-07-01

    Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation and distributed energy sector of Brazilian economy. Fossil fuels are polluting by carbogenic emissions from their combustion, being so co-responsible for present global warming. However, no large scale, cost-effective, environmentally non-carbogenic hydrogen production process is currently available for commercialization. There are feasible possibilities to use electrolysis as one of the main sources of hydrogen, especially thinking on combination with renewable sources of energy, mainly eolic and solar. In this work some perspectives for Brazilian energy context is presented, where electrolysis combined with renewable power source and fuel cell power generation would be a good basis to improve the distributed energy supply for remote areas, where the electricity grid is not present or is deficient. (author)

  8. Hydrogen production from fusion reactors coupled with high temperature electrolysis

    International Nuclear Information System (INIS)

    The decreasing availability of fossil fuels emphasizes the need to develop systems which will produce synthetic fuel to substitute for and complement the natural supply. An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Processes which may be considered for this purpose include electrolysis, thermochemical decomposition or thermochemical-electrochemical hybrid cycles. Preliminary studies at Brookhaven indicate that high temperature electrolysis has the highest potential efficiency for production of hydrogen from fusion. Depending on design electric generation efficiencies of approximately 40 to 60 percent and hydrogen production efficiencies of approximately 50 to 70 percent are projected for fusion reactors using high temperature blankets

  9. HYFIRE: a tokamak/high-temperature electrolysis system

    International Nuclear Information System (INIS)

    The HYFIRE studies to date have investigated a number of technical approaches for using the thermal energy produced in a high-temperature Tokamak blankets to provide the electrical and thermal energy required to drive a high-temperature (>10000C) water electrolysis process. Current emphasis is on two design points, one consistent with electrolyzer peak inlet temperatures of approx. 13000C, which is an extrapolation of present experience, and one consistent with a peak electrolyzer temperature of 11000C. This latter condition is based on current laboratory experience with high-temperature solid electrolyte fuel cells. Our major conclusion to date is that the technical integration of fusion and high-temperature electrolysis appears to be feasible and that overall hydrogen production efficiencies of 50 to 55% seem possible

  10. HYFIRE: a tokamak/high-temperature electrolysis system

    International Nuclear Information System (INIS)

    The HYFIRE studies to date have investigated a number of technical approaches for using the thermal energy produced in a high-temperature Tokamak blanket to provide the electrical and thermal energy required to drive a high-temperature (> 10000C) water electrolysis process. Current emphasis is on two design points, one consistent with electrolyzer peak inlet temperatures of 14000C, which is an extrapolation of present experience, and one consistent with a peak electrolyzer temperature of 11000C. This latter condition is based on current laboratory experience with high-temperature solid electrolyte fuel cells. Our major conclusion to date is that the technical integration of fusion and high-temperature electrolysis appears to be feasible and that overall hydrogen production efficiencies of 50 to 55% seem possible

  11. Bipolar electrolysis for tritium recovery from weakly active tritiated water

    International Nuclear Information System (INIS)

    Detritiation facilities produce low activity tritiated water from which tritium cannot be recovered. Bipolar electrolysis, based on the electrochemical permeation of hydrogen and its isotopes through Pd-Ag alloy membranes, allows tritiated water enrichment together with negligible gaseous tritium release. Our purpose is to enrich water from 500 Ci/l (1.85x1013 Bq/l) to more than 2000 Ci/l (7.40x1013 Bq/l). We first describe the principle of bipolar electrolysis and its application to isotopic enrichment. The experimental part of this work consists of the determination of the isotopic separation factors. From these experimental values, we simulated the working of an operational cell and we demonstrate the feasibility of the process

  12. Mathematical Analysis of High-Temperature Co-electrolysis of CO2 and O2 Production in a Closed-Loop Atmosphere Revitalization System

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; Manohar S. Sohal; Lila Mulloth; Bernadette Luna; Morgan B. Abney

    2010-03-01

    NASA has been evaluating two closed-loop atmosphere revitalization architectures based on Sabatier and Bosch carbon dioxide, CO2, reduction technologies. The CO2 and steam, H2O, co-electrolysis process is another option that NASA has investigated. Utilizing recent advances in the fuel cell technology sector, the Idaho National Laboratory, INL, has developed a CO2 and H2O co-electrolysis process to produce oxygen and syngas (carbon monoxide, CO and hydrogen, H2 mixture) for terrestrial (energy production) application. The technology is a combined process that involves steam electrolysis, CO2 electrolysis, and the reverse water gas shift (RWGS) reaction. A number of process models have been developed and analyzed to determine the theoretical power required to recover oxygen, O2, in each case. These models include the current Sabatier and Bosch technologies and combinations of those processes with high-temperature co-electrolysis. The cases of constant CO2 supply and constant O2 production were evaluated. In addition, a process model of the hydrogenation process with co-electrolysis was developed and compared. Sabatier processes require the least amount of energy input per kg of oxygen produced. If co-electrolysis replaces solid polymer electrolyte (SPE) electrolysis within the Sabatier architecture, the power requirement is reduced by over 10%, but only if heat recuperation is used. Sabatier processes, however, require external water to achieve the lower power results. Under conditions of constant incoming carbon dioxide flow, the Sabatier architectures require more power than the other architectures. The Bosch, Boudouard with co-electrolysis, and the hydrogenation with co-electrolysis processes require little or no external water. The Bosch and hydrogenation processes produce water within their reactors, which aids in reducing the power requirement for electrolysis. The Boudouard with co-electrolysis process has a higher electrolysis power requirement because carbon

  13. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  14. Silica enigma and ignorance in alkali

    International Nuclear Information System (INIS)

    Si migration and K, Na alterations are two key problems for understanding the whole process of hydrothermal metallogenesis, but they have not attracted sufficient attention of geologists for a long time. It is impossible for us to know hydrothermal metallogenetic regularity actually without studying dequartzfication and alkali-introduction. Being distinct from common habitual thinking, it is considered that ore-forming elements are micro-amount, passive subordinate components in the flow of hydrothermal matter movement, and there is no metallogenesis for a certain element in nature. Except that the ore source is controlled by the uneven distribution ore-forming elements in the mantle and crust the same metallogenesis may almost lead to the formation of deposits of all elements. Principal active components in the hydrothermal matter system include alkali, silica and acid volatiles. The ternary system has determined the fate of release, activation, migration, precipitaion and concentration of ore-forming elements. Each member of the ternary system plays a different role in metallogenesis, having marvellous functional division of work. of these three members main control factor is alkali metal, whereas silica and acid are constrained by alkali. Acidic matter (including silica) and ore-forming elements are derivatives from activities of alkali metals

  15. Evidence of Production of Neutral Cl35 Atoms by the Cl35 (n, p)S35 Process in Alkali Metal Chlorides

    International Nuclear Information System (INIS)

    A number of investigations reported in the literature have shown that S35 produced by the Cl35 (n, p)S35 process in neutron-irradiated alkali metal halides may be separated as S= , SO=3 and SO=4 after the irradiated crystals are dissolved in aqueous solutions of the appropriate carriers. The relative amounts of the three chemical forms depend on the purity of the sample and the conditions of irradiation and analysis. Attempts to identify neutral S35 atoms among the products of the neutron irradiation have been limited by the fact that elemental sulphur is too insoluble to use as a carrier in aqueous solution and by the exchange and adsorption processes which interfere when heterogeneous extraction processes are used. However, we have observed chemical evidence for an S35 species with properties which might be expected for neutral monatomic sulphur. When vacuum-sublimed, neutron-irradiated KCl is dissolved in degassed 0.3N aqueous NaOH containing S=, SO=3 and SO=4 , analysis for the three species typically shows 90% of the S35 activity as S=, 7% as SO=3 and 3% as SO=4 . When an identical experiment is done in which the carriers are added to the 0.3N NaOH solution after adding the KCl the typical S35 yields are 30% S=, 30% SO3 and 40% SO=4. Thus some 60% of the S35 species found in the S=3 fraction when the KCl is dissolved in the presence of carriers is found as SO=4 and SO=3 when the carriers are added after dissolution of the KCl. Since monatomic sulphur is thermodynamically unstable in H2O with respect to oxidation (ΔF = -5900 kcal/mole for S + 4H2O → 3H2O → 3H2 + H2SO4), and since it would also be expected to exchange readily with S= carrier these results suggest that some 60% of the S35 may be present in the irradiated KCl crystals as neutral monatomic S. Similar evidence for neutral S35 atoms has been obtained from neutron-irradiated crystals of NaCl, RbCl and CsCl. The effects of S= carrier concentration at the time of dissolution and of gamma

  16. A model-based understanding of solid-oxide electrolysis cells (SOECs) for syngas production by H2O/CO2 co-electrolysis

    Science.gov (United States)

    Menon, Vikram; Fu, Qingxi; Janardhanan, Vinod M.; Deutschmann, Olaf

    2015-01-01

    High temperature co-electrolysis of H2O and CO2 offers a promising route for syngas (H2, CO) production via efficient use of heat and electricity. The performance of a SOEC during co-electrolysis is investigated by focusing on the interactions between transport processes and electrochemical parameters. Electrochemistry at the three-phase boundary is modeled by a modified Butler-Volmer approach that considers H2O electrolysis and CO2 electrolysis, individually, as electrochemically active charge transfer pathways. The model is independent of the geometrical structure. A 42-step elementary heterogeneous reaction mechanism for the thermo-catalytic chemistry in the fuel electrode, the dusty gas model (DGM) to account for multi-component diffusion through porous media, and a plug flow model for flow through the channels are used in the model. Two sets of experimental data are reproduced by the simulations, in order to deduce parameters of the electrochemical model. The influence of micro-structural properties, inlet cathode gas velocity, and temperature are discussed. Reaction flow analysis is performed, at OCV, to study methane production characteristics and kinetics during co-electrolysis. Simulations are carried out for configurations ranging from simple one-dimensional electrochemical button cells to quasi-two-dimensional co-flow planar cells, to demonstrate the effectiveness of the computational tool for performance and design optimization.

  17. Synthesis, structure peculiarities and electric conductivity of alkali metal-rare earth silicates (germanates)

    International Nuclear Information System (INIS)

    The process of obtaining of rare earth-alkali metal silicates (germanates) is studied. The analysis of possibilities of structural disordering of alkaline cations in these structures is given. The interaction of the structure of different by the composition alkali alkali metal - rare earth silicates with electric conductivity values is shown

  18. Bio-Fuel Production Assisted with High Temperature Steam Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Grant Hawkes; James O' Brien; Michael McKellar

    2012-06-01

    Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model

  19. Studies of water electrolysis in polymeric membrane cells; Estudos de eletrolise aquosa em celulas de membrana polimerica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira-Silva, M.A.; Linardi, M.; Saliba-Silva, A.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Celulas a Combustivel e Hidrogenio

    2010-07-01

    Hydrogen represents great opportunity to be a substitute for fossil fuels in the future. Water as a renewable source of hydrogen is of great interest, since it is abundant and can decompose, producing only pure H{sub 2} and O{sub 2}. This decomposition of water can be accomplished by processes such as electrolysis, thermal decomposition and thermochemical cycles. The membrane electrolysis has been proposed as a viable process for hydrogen production using thermal and electrical energy derived from nuclear energy or any renewable source like solar energy. In this work, within the context of optimization of the electrolysis process, it is intended to develop a mathematical model that can simulate and assist in parameterization of the electrolysis performed by polymer membrane electrolytic cell. The experimental process to produce hydrogen via the cell membrane, aims to optimize the amount of gas produced using renewable energy with non-carbogenic causing no harm by producing gases deleterious to the environment. (author)

  20. The Additive Coloration of Alkali Halides

    Science.gov (United States)

    Jirgal, G. H.; and others

    1969-01-01

    Describes the construction and use of an inexpensive, vacuum furnace designed to produce F-centers in alkali halide crystals by additive coloration. The method described avoids corrosion or contamination during the coloration process. Examination of the resultant crystals is discussed and several experiments using additively colored crystals are…

  1. Positronium impact ionization of Alkali atoms

    CERN Document Server

    Ghosh, D

    2015-01-01

    Target ionization processes of alkali atoms by Positronium impact are investigated. Calculations are performed in the frame work of model potential formalism using the Coulomb distorted eikonal approximation. Interesting qualitative features are noted both in the scattered Ps and the ejected electron distributions in differential as well as double differential levels of the collision cross sections.

  2. Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

    DEFF Research Database (Denmark)

    Clausen, Lasse Røngaard; Houbak, N.; Elmegaard, Brian

    2010-01-01

    Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2...... different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59-72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the...... low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (similar to 90%) for the plants. The specific methanol costs for the six plants are in the range 11.8-25.3 (sic)/GJ(exergy). The lowest cost is obtained by a plant using electrolysis of...

  3. Solid polymer electrolyte water electrolysis

    Science.gov (United States)

    Takenaka, H.; Torikai, E.; Kawami, Y.; Wakabayashi, N.

    Electrocatalyst performances and bonding to solid polymer electrolytes used for water electrolysis are investigated. Noble metal and metal alloy catalysts were plated to Nafion perfluorosulfonic acid polymer membranes without a binder by the use of a reducing agent solution held on the opposite side of the membrane from a metal salt solution. It was found that pretreatment of the membrane by hydrothermal treatment or gas plasma surface roughening improves metal adhesivity and thus reduces contact resistance between the membrane and the catalyst. Measurements of the constituents of cell voltage for platinum, rhodium and iridium anodes with platinum cathodes reveals that anodic overvoltage is a major component of voltage loss and depends on the type of electrocatalyst, being greatest for Pd and least for Ir. Ir and Ir-alloy electrodes, which were found to be the best catalysts for oxygen evolution, are found to have Tafel slopes of 0.04-0.06 V/decade. In a cell with a Pt cathode and Ir anode, cell voltage is observed to decrease with increasing temperature, reaching 1.56-1.59 V at a current density of 50 A/sq dm and 90 C, which corresponds to a thermal efficiency of 93-95%.

  4. The Role of Key Impurity Elements on the Performance of Aluminium Electrolysis - Current Efficiency and Metal Quality

    OpenAIRE

    Al-Mejali, Jassim Ali

    2015-01-01

    Impurities such as phosphorus and silicon mainly enter the aluminium electrolysis process with alumina. These impurities dissolve in the electrolyte and affect the performance of the electrolysis, the emissions from the cells and the quality of the metal produced. In the present work, the behavior of phosphorus and silicon species in the industrial Hall-Héroult cells was investigated. The study was based on the deleterious effect of phosphorus and silicon on the aluminium production process. ...

  5. Parametric Study Of Large-Scale Production Of Syngas Via High Temperature Co-Electrolysis

    International Nuclear Information System (INIS)

    A process model has been developed to evaluate the potential performance of a large-scale high-temperature co-electrolysis plant for the production of syngas from steam and carbon dioxide. The co-electrolysis process allows for direct electrochemical reduction of the steam-carbon dioxide gas mixture, yielding hydrogen and carbon monoxide, or syngas. The process model has been developed using the Honeywell UniSim systems analysis code. Using this code, a detailed process flow sheet has been defined that includes all the components that would be present in an actual plant such as pumps, compressors, heat exchangers, turbines, and the electrolyzer. Since the electrolyzer is not a standard UniSim component, a custom one-dimensional co-electrolysis model was developed for incorporation into the overall UniSim process flow sheet. The one dimensional co-electrolysis model assumes local chemical equilibrium among the four process-gas species via the gas shift reaction. The electrolyzer model allows for the determination of co-electrolysis outlet temperature, composition (anode and cathode sides); mean Nernst potential, operating voltage and electrolyzer power based on specified inlet gas flow rates, heat loss or gain, current density, and cell area-specific resistance. The one-dimensional electrolyzer model was validated by comparison with results obtained from a fully three dimensional computational fluid dynamics model developed using FLUENT, and by comparison to experimental data. This paper provides representative results obtained from the UniSim flow sheet model for a 300 MW co-electrolysis plant, coupled to a high-temperature gas-cooled nuclear reactor. The coelectrolysis process, coupled to a nuclear reactor, provides a means of recycling carbon dioxide back into a useful liquid fuel. If the carbon dioxide source is based on biomass, the overall process, from production through utilization, would be climate neutral

  6. The influence of electrolyte concentration, voltage and time on uranium content in the electrolysis of U3Si2-Al fuel plate

    International Nuclear Information System (INIS)

    Research on the influence of electrolyte concentration, voltage and time on uranium content in the electrolysis of U3Si2-Al fuel plate has been conducted. In the previous research, electrolysis process of U3Si2-Al fuel plate resulted in the gaining of 4.536 g of U3Si2 powder, in which some of the uranium was dissolved in the electrolyte as a contaminant. If not treated, the dissolved uranium content will increase and may interfere with the subsequent electrolysis process. The uranium contaminant, therefore, needs to be recovered. In this research, during the electrolysis process, sampling of electrolyte was done to determine the uranium content. The experiment showed that a relatively good condition was achieved in the electrolysis process with an electrolyte concentration of 2 N for 90 minutes at 4 volts. In this condition, the uranium content as the contaminant was found to be 125 mg/L. (author)

  7. Analysis on Alkali Metal Migration Law in Process of Eucalyptus Branches Direct Combustion%桉树枝直燃利用过程中碱金属迁移规律分析

    Institute of Scientific and Technical Information of China (English)

    韦威; 廖艳芬; 陈拓; 马晓茜; 杨云金; 余勇强

    2014-01-01

    For knowing alkali metal migration law in eucalyptus branches burned in some biomass power plant,this paper studies it by combustion experiment.The experimental sample is eucalyptus branch particle with grain size of 1 80μm which is used for repeat combustion experiment in pipe burner in order to get residual samples under different temperatures and with different combustion time.By proximate analysis on residual samples,it is able to get combustion laws of volatiles and fixed carbon.The experimental result shows that volatility of alkali metal in eucalyptus branches is very strong and there is 87%potassium released into gas phase in process of high temperature burning.Meanwhile,precipitation of alkali metal is speeding up with increase of temperature and precipitation volume dose is increasing with temperature and stop time.In addition,tak-ing kaolin as additive,it conducts quantitative analysis on its impact on retention rate of alkali metal in ash.The analysis re-sult indicates that kaolin has very good retention role for alkali metal in eucalyptus branches and retention effect of 5% kao-lin is the best.%为了解某生物质电厂燃用的桉树枝的碱金属迁移规律,对其进行了燃烧实验研究。实验样品为粒径180μm的桉树枝颗粒,在管式燃烧器中进行燃烧重复实验,获得不同温度和燃烧时间下的残留物样品,然后对残留物进行工业分析,获得挥发分、固定碳的燃烧规律;实验结果表明桉树枝碱金属挥发性很强,高温燃尽时有87%的钾释放进入气相,碱金属的析出随温度的增高而加快,析出总量也随温度和停留时间而增加。另外,以高岭土作为添加剂,定量分析了其对桉树枝碱金属在灰渣中的固留率的影响,分析结果表明高岭土对桉树枝的碱金属有很好固留作用,5%的高岭土添加量固留效果最佳。

  8. 基于混合粒子群算法的锌电解过程能耗优化%Energy Consumption Optimization of Zinc Electrolysis Process Based on Hybrid Particle Swarm Algorithm

    Institute of Scientific and Technical Information of China (English)

    桂卫华; 张美菊; 阳春华; 李勇刚

    2009-01-01

    To high energy consumption of zinc electrolysis process(ZEP), the energy consumption optimization problem is discussed. According to the time-sharing price policy of electric power, a multi-objective optimization model of ZEP is established . A particle swarm optimization algorithm with accelerated velocity (AVPSO)is proposed. The sustainable searching ability of the algorithm is obtained by the accelerate strategy to the population particles velocity updating, so the premature convergence problem is overcome in effect . The AVPSO is combined with Powell to build a new hybrid PSO(HPSO) algorithm,which employs the global and local searching ability brought by PSO algorithm and Powell algorithm. The HPSO is applied to the multi-objective optimization model to obtain the optimal production scheme. The simulation results show the effectiveness of the proposed algorithm,and the practical application results show that the power consumption and its cost are decreased by using the optimal production scheme.%针对锌电解过程能耗过高的情况,研究其能耗优化问题.根据电力部门实行的分时计价政策,建立以全天锌电解过程电能消耗和总用电费用为目标的锌电解过程多目标优化模型.提出一种带加速度调整的粒子群优化算法,当粒子陷入局部最优时,通过加速度策略增强种群速度,使算法获得持续搜索的能力,有效克服早熟收敛;并和Powell算法相结合构成新的混合粒子群算法,将粒子群算法的全局搜索能力与Powell算法的局部寻优能力有机结合起来.最后将该混合粒子群算法应用于所建优化模型的求解,获得优化生产方案.仿真结果证明了该算法的有效性.工业应用效果表明,按所得优化方案组织生产降低了电能消耗,减少了用电费用.

  9. Elimination of heavy metals from leachates by membrane electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, R. [Technische Universitaet Dresden, Institut fuer Siedlungs- und Industriewasserwirtschaft, Mommsenstrasse 13, 01062 Dresden (Germany); Seidel, H. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Bioremediation, Permoserstrasse 15, D-04318 Leipzig (Germany); Rahner, D. [Technische Universitaet Dresden, Institut fuer Physikalische Chemie und Eektrochemie, Mommsenstrasse 13, D-01062 Dresden (Germany); Morgenstern, P. [UFZ-Umweltforschungszentrum Leipzig-Halle GmbH, Department Analytik, Permoserstrasse 15, D-04318 Leipzig (Germany); Loeser, C. [Technische Universitaet Dresden, Institut fuer Lebensmittel- und Bioverfahrenstechnik, Bergstrasse 120, D-01062 Dresden (Germany)

    2004-10-01

    The elimination of heavy metals from bioleaching process waters (leachates) by electrolysis was studied in the anode and cathode region of a membrane electrolysis cell at current densities of 5-20 mA/cm{sup 2} using various electrode materials. The leaching waters containing a wide range of dissolved heavy metals, were high in sulfate, and had pH values of approx. 3. In preliminary tests using a rotating disc electrode the current density-potential curve (CPK) was recorded at a rotation velocity of 0, 1000 and 2000 rpm and a scan rate of 10 mV/s in order to collect information on the influence of transport processes on the electrochemical processes taking place at the electrodes. The electrochemical deposition-dissolution processes at the cathode are strongly dependent on the hydrodynamics. Detailed examination of the anodic oxidation of dissolved Mn(II) indicated that the manganese dioxide which formed adhered well to the electrode surface but in the cathodic return run it was again reduced. Electrode pairs of high-grade steel, lead and coal as well as material combinations were used to investigate heavy metal elimination in a membrane electrolysis cell. Using high-grade steel, lead and carbon electrode pairs, the reduction and deposition of Cu, Zn, Cr, Ni and some Cd in metallic or hydroxide form were observed in an order of 10-40 % in the cathode chamber. The dominant process in the anode chamber was the precipitation of manganese dioxide owing to the oxidation of dissolved Mn(II). Large amounts of heavy metals were co-precipitated by adsorption onto the insoluble MnO{sub 2}. High-grade steel and to some extent lead anodes were dissolved and hence were proven unsuitable as an anode material. These findings were largely confirmed by experiments using combination electrodes of coal and platinized titanium as an anode material and steel as a cathode material.The results indicate that electrochemical metal separation in the membrane electrolysis cell can represent a

  10. 2nd Generation alkaline electrolysis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Yde, L. [Aarhus Univ. Business and Social Science - Centre for Energy Technologies (CET), Aarhus (Denmark); Kjartansdottir, C.K. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Allebrod, F. [Technical Univ. of Denmark. DTU Energy Conversion, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2013-03-15

    The overall purpose of this project has been to contribute to this load management by developing a 2{sup nd} generation of alkaline electrolysis system characterized by being compact, reliable, inexpensive and energy efficient. The specific targets for the project have been to: 1) Increase cell efficiency to more than 88% (according to the higher heating value (HHV)) at a current density of 200 mA /cm{sup 2}; 2) Increase operation temperature to more than 100 degree Celsius to make the cooling energy more valuable; 3) Obtain an operation pressure more than 30 bar hereby minimizing the need for further compression of hydrogen for storage; 4) Improve stack architecture decreasing the price of the stack with at least 50%; 5) Develop a modular design making it easy to customize plants in the size from 20 to 200 kW; 6) Demonstrating a 20 kW 2{sup nd} generation stack in H2College at the campus of Arhus University in Herning. The project has included research and development on three different technology tracks of electrodes; an electrochemical plating, an atmospheric plasma spray (APS) and finally a high temperature and pressure (HTP) track with operating temperature around 250 deg. C and pressure around 40 bar. The results show that all three electrode tracks have reached high energy efficiencies. In the electrochemical plating track a stack efficiency of 86.5% at a current density of 177mA/cm{sup 2} and a temperature of 74.4 deg. C has been shown. The APS track showed cell efficiencies of 97%, however, coatings for the anode side still need to be developed. The HTP cell has reached 100 % electric efficiency operating at 1.5 V (the thermoneutral voltage) with a current density of 1. 1 A/cm{sup 2}. This track only tested small cells in an externally heated laboratory set-up, and thus the thermal loss to surroundings cannot be given. The goal set for the 2{sup nd} generation electrolyser system, has been to generate 30 bar pressure in the cell stack. An obstacle to be

  11. Steam electrolysis cell system and electrolyzing method

    International Nuclear Information System (INIS)

    The present invention concerns a method effective to the electrolysis of tritium water in a tritium recovering system of a thermonuclear fuel system. Namely, in a steam electrolysis cell system including integrally constituted multistage type cells and independently disposed single stage type cell, steams are supplied from upstream to the multistage type cell. A voltage is applied at such a level that the concentration of the steams in the vicinity of the single stage type cell situated at the downmost stream among the cells is not decreased to 0 to electrolyze steams. Then, not yet decomposed steams are introduced to the single stage cell to complete the electrolysis. The device can be simplified and steams can be electrolyzed efficiently. (N.H.)

  12. Production of Oxygen from Lunar Regolith by Molten Oxide Electrolysis

    Science.gov (United States)

    Curreri, Peter A.

    2009-01-01

    This paper describes the use of the molten oxide electrolysis (MOE) process for the extraction of oxygen for life support and propellant, and silicon and metallic elements for use in fabrication on the Moon. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis is ideal for extraction, since the electron is the only practical reducing agent. MOE has several advantages over other extraction methods. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. Alternatively, MOE requires no import of consumable reagents (e.g. fluorine and carbon) as other processes do, and does not rely on interfacing multiple processes to obtain refined products. Electrolytic processing has the advantage of selectivity of reaction in the presence of a multi-component feed. Products from lunar regolith can be extracted in sequence according to the stabilities of their oxides as expressed by the values of the free energy of oxide formation (e.g. chromium, manganese, Fe, Si, Ti, Al, magnesium, and calcium). Previous work has demonstrated the viability of producing Fe and oxygen from oxide mixtures similar in composition to lunar regolith by molten oxide electrolysis (electrowinning), also called magma electrolysis having shown electrolytic extraction of Si from regolith simulant. This paper describes recent advances in demonstrating the MOE process by a joint project with participation by NASA KSC and

  13. Kinetics of molybdenite oxidizing leaching in alkali medium by ozone

    International Nuclear Information System (INIS)

    On the basis of investigation of the process kinetics proposed is a model of oxidizing leaching of molybdenite in alkali medium while ozonization of the solution by ozoneair mixture. A kinetic equation is derived, that describes experimental data satisfactorily

  14. Poisoning of Solid Oxide Electrolysis Cells by Impurities

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Graves, Christopher R.; Hauch, Anne;

    2010-01-01

    Electrolysis of H2O, CO2, and co-electrolysis of H2O and CO2 was studied in Ni/yttria-stabilized zirconia (YSZ) electrode supported solid oxide electrolysis cells (SOECs) consisting of a Ni/YSZ support, a Ni/YSZ electrode layer, a YSZ electrolyte, and an lanthanum strontium manganite (LSM)/YSZ ox...

  15. 21 CFR 886.4250 - Ophthalmic electrolysis unit.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic electrolysis unit. 886.4250 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4250 Ophthalmic electrolysis unit. (a) Identification. An ophthalmic electrolysis unit is an AC-powered or battery-powered device intended to...

  16. Thermodynamic evaluation of geothermal energy powered hydrogen production by PEM water electrolysis

    International Nuclear Information System (INIS)

    Thermodynamic energy and exergy analysis of a PEM water electrolyzer driven by geothermal power for hydrogen production is performed. For this purpose, work is produced from a geothermal resource by means of the organic Rankine cycle; the resulting work is used as a work input for an electrolysis process; and electrolysis water is preheated by the waste geothermal water. The first and second-law based performance parameters are identified for the considered system and the system performance is evaluated. The effects of geothermal water and electrolysis temperatures on the amount of hydrogen production are studied and these parameters are found to be proportional to each other. We consider a geothermal resource at 160 °C available at a rate of 100 kg/s. Under realistic operating conditions, 3810 kW power can be produced in a binary geothermal power plant. The produced power is used for the electrolysis process. The electrolysis water can be preheated to 80 °C by the geothermal water leaving the power plant and hydrogen can be produced at a rate of 0.0340 kg/s. The energy and exergy efficiencies of the binary geothermal power plant are 11.4% and 45.1%, respectively. The corresponding efficiencies for the electrolysis system are 64.0% and 61.6%, respectively, and those for the overall system are 6.7% and 23.8%, respectively. - Highlights: • Thermodynamic analysis of hydrogen production by PEM electrolysis powered by geothermal energy. • Power is used for electrolyser; used geothermal water is for preheating electrolysis water. • Effect of geothermal water and electrolysis temperatures on the amount of hydrogen production. • Hydrogen can be produced at a rate of 0.0340 kg/s for a resource at 160 °C available at 100 kg/s. • Energy and exergy efficiencies of the overall system are 6.7% and 23.8%, respectively

  17. Alkali Aggregate Reaction in Alkali Slag Cement Mortars

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By means of "Mortar Bar Method",the ratio of cement to aggregate was kept as a constant 1∶2.25,the water-cement ratio of the mixture was 0.40,and six prism specimens were prepared for each batch of mixing proportions with dimensions of 10×10×60mm3 at 38±2℃ and RH≥95%, the influences of content and particle size of active aggregate, sort and content of alkali component and type of slag on the expansion ratios of alkali-activated slag cement(ASC) mortars due to alkali aggregate reaction(AAR) were studied. According to atomic absorption spectrometry,the amount of free alkali was measured in ASC mortars at 90d.The results show above factors affect AAR remarkably,but no dangerous AAR will occur in ASC system when the amount of active aggregate is below 15% and the mass fraction of alkali is not more than 5% (Na2O).Alkali participated in reaction as an independent component, and some hydrates containing alkali cations were produced, free alkalis in ASC system can be reduced enormously.Moreover,slag is an effective inhibitor, the possibility of generating dangerous AAR in ASC system is much lower at same conditions than that in ordinary Portland cement system.

  18. A Control Strategy for Photovoltaic-Solid Polymer Electrolysis System Based on Surface Temperature of PV Panel

    OpenAIRE

    Riza Muhida; Wahyudi; Rifki Muhida; Ahmad U. Priantoro

    2008-01-01

    Processes to produce hydrogen from solar photovoltaic powered water electrolysis using solid polymer electrolysis are reported. An alternative control of maximum power point tracking method based on analysis of PV panels surface Temperature for the PV-SPE system was designed and implemented. From this analysis an optimal voltage of PV can be obtained and was realized as a reference voltage of Dc-DC converter. By maintenance the output voltage of PV using the reference voltage control, the out...

  19. On-board hydrogen storage and production: An application of ammonia electrolysis

    Science.gov (United States)

    Boggs, Bryan K.; Botte, Gerardine G.

    On-board hydrogen storage and production via ammonia electrolysis was evaluated to determine whether the process was feasible using galvanostatic studies between an ammonia electrolytic cell (AEC) and a breathable proton exchange membrane fuel cell (PEMFC). Hydrogen-dense liquid ammonia stored at ambient temperature and pressure is an excellent source for hydrogen storage. This hydrogen is released from ammonia through electrolysis, which theoretically consumes 95% less energy than water electrolysis; 1.55 Wh g -1 H 2 is required for ammonia electrolysis and 33 Wh g -1 H 2 for water electrolysis. An ammonia electrolytic cell (AEC), comprised of carbon fiber paper (CFP) electrodes supported by Ti foil and deposited with Pt-Ir, was designed and constructed for electrolyzing an alkaline ammonia solution. Hydrogen from the cathode compartment of the AEC was fed to a polymer exchange membrane fuel cell (PEMFC). In terms of electric energy, input to the AEC was less than the output from the PEMFC yielding net electrical energies as high as 9.7 ± 1.1 Wh g -1 H 2 while maintaining H 2 production equivalent to consumption.

  20. Electrolysis byproduct D2O provides a third way to mitigate CO2

    International Nuclear Information System (INIS)

    Rapid atomic power deployment may be possible without using fast breeder reactors or making undue demands on uranium resource. Using by-product D2O and thorium-U233 in CANDU and RBMK piles may circumvent need for either fast breeder reactors or seawater uranium. Atmospheric CO2 is presently increasing 2.25%/year in proportion to 2.25%/year exponential fossil fuel consumption increase. Roughly 1/3 anthropologic CO2 is removed by various CO2 sinks. CO2 removal is modelled as being proportional to 45-year-earlier CO2 amount above 280 ppm-C Water electrolysis produces roughly 0.1 kg-D20/kWe-y. Material balance assumes each electrolysis stage increases D2O bottoms concentration times 3. Except for first two electrolysis stages, all water from hydrogen consumption is returned to electrolysis. The unique characteristic of this process is the ability to economically burn all deuterium-enriched H2 in vehicles. Condensate from vehicles returns to appropriate electrolysis stage. Fuel cell condensate originally from reformed natural gas may augment second-sage feed. Atomic power expansion is 5%/year, giving 55000 GWe by 2100. World primary energy increases 2.25%/y, exceeding 4000 EJ/y by 2100. CO2 maximum is roughly 600 ppm-C around year 2085. CO2 declines back below 300 ppm-C by 2145 if the 45-year-delay seawater sink remains effective

  1. Natural Alkali Shifts to the Methanol Business

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Inner Mongolia Yuanxing Natural Alkali Co., Ltd. (Natural Alkali SZ: 000683) established in 1997 is a large chemical enterprise with new energy as its leading business and natural gas chemicals and natural alkali chemicals as the supplement business.

  2. Plastic properties of tunsten produced by electrolysis of molten salts

    International Nuclear Information System (INIS)

    A study is made into bend ductility, microhardness and texture of tungsten produced by electrolysis of CsCl and KCl-NaF molten salts. The influence of texture and high temperature annealing on ductile-brittle transition temperature was determined using specimens of electrolytic tungsten coatings 0.3 mm thick. For tungsten specimens of perfect texture [111] transition temperature constitutes 250 deg C. High temperature annealing (1400 deg C 4 h) raises the temperature of ductile-brittle transition. This fact may be related to the process of impurity concentration on grain boundaries which length decreases on annealing. 8 refs., 3 figs.2 tabs

  3. Electrochemical investigation of surface area effects on PVD Al-Ni as electrocatalyst for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín; Caspersen, Michael; Egelund, Sune Daaskov; Møller, Per

    2014-01-01

    A thermo-chemical diffusion of vapour deposited aluminium onto a nickel substrate, leads to a rapid formation of an Al/Ni intermetallic layer that is particularly acceptable for dissolution of aluminium in strong alkali. The geometry and the structure of the final skeletal nickel coatings can be ...... to above 2000, additional 40mV are gained. For the OER, smaller roughness values were observed with the same activity trend as for the HER. The electrocatalyst are however found not to be stable in the anodic environment during electrolysis. The corrosion mechanism of a skeletal nickel...

  4. Electrochemical investigation of surface area effects on PVD Al-Ni as electrocatalyst for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín; Caspersen, Michael; Egelund, Sune Daaskov;

    2014-01-01

    A thermo-chemical diffusion of vapour deposited aluminium onto a nickel substrate, leads to a rapid formation of an Al/Ni intermetallic layer that is particularly acceptable for dissolution of aluminium in strong alkali. The geometry and the structure of the final skeletal nickel coatings can be...... to above 2000, additional 40mV are gained. For the OER, smaller roughness values were observed with the same activity trend as for the HER. The electrocatalyst are however found not to be stable in the anodic environment during electrolysis. The corrosion mechanism of a skeletal nickel...

  5. Material characteristics and behaviour of highly deuterium loaded palladium by electrolysis

    International Nuclear Information System (INIS)

    Studies on several kinds of palladium cathodes have been conducted in electrochemical cells using LiOD/D2O electrolyte to determine necessary and sufficient conditions for attaining high deuterium loading. Comparative observations of the microstructure and analysis of surface impurities have been carried out on palladium specimens with various pre-electrolysis treatments and post electrolysis. From the observations and analysis of various processed and treated Pd specimens, the material characteristics of a Pd cathode achieving high loading ratios (D/Pd>0.85) are discussed. (orig.)

  6. Modification of the EN AC-42000 aluminium alloy with use of multicomponent electrolysis of sodium salt

    OpenAIRE

    J. Pezda

    2014-01-01

    The present paper discusses results of research concerning the process of continuous modification of the EN AC-42000 (AlSi7Mg) alloy with sodium, based on electrolysis of sodium salts, occurring directly in a melting pot with the liquid alloy. Sodium ions formed as a result of dissociation of the sodium salt and the electrolysis are “transferred” through walls of the retort made from solid electrolyte. Upon contact with the liquid alloy, as a cathode, sodium ions are transformed into atomic s...

  7. Base-acid hybrid water electrolysis.

    Science.gov (United States)

    Chen, Long; Dong, Xiaoli; Wang, Fei; Wang, Yonggang; Xia, Yongyao

    2016-02-21

    A base-acid hybrid electrolytic system with a low onset voltage of 0.78 V for water electrolysis was developed by using a ceramic Li-ion exchange membrane to separate the oxygen-evolving reaction (OER) in a basic electrolyte solution containing the Li-ion and hydrogen-evolving reaction (HER) in an acidic electrolyte solution. PMID:26804323

  8. Fabrication of nanostructures by plasma electrolysis

    CERN Document Server

    Aliofkhazraei, Mahmood

    2011-01-01

    In this handbook and ready reference, the authors introduce the concept of plasma electrolysis, explaining how the coatings are characterized and discussing their mechanical and corrosion properties. They then go on to look at specific industrial applications of this powerful and low-cost method, including aerospace, the biomaterials industry as well as in the oil and gas industry.

  9. Additional considerations on electrolysis in electromembrane extraction

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    2016-01-01

    Roč. 1429, JAN (2016), s. 364-368. ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electrolysis * electromembrane extraction * extraction recovery and quantity Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014

  10. H2O/CO2 co-electrolysis in solid oxide electrolysis cells

    Institute of Scientific and Technical Information of China (English)

    Han Minfang; Fan Hui; Peng Suping

    2014-01-01

    A solid oxide electrolysis cell (SOEC) is an environmental-friendly device which can convert electric energy into chemical energy with high efficiency. In this paper,the progress on structure and operational princi-ple of an SOEC for co-electrolyzing H2O and CO2 to generate syngas was reviewed. The recent development of high temperature H2O/CO2 co-electrolysis from solid oxide single electrolysis cell was introduced. Also investi-gated was H2O/CO2 co-electrolysis research using hydrogen electrode-supported nickel (Ni)-yttria-stabilized zir-conia (YSZ)/YSZ/Sr-doped LaMnO3 (LSM)-YSZ cells in our group. With 50%H2O,15.6%H2 and 34.4%CO2 inlet gas to Ni-YSZ electrode,polarization curves (I-U curves) and electrochemical impedance spectra (EIS) were measured at 800℃and 900℃. Long-term durability of electrolysis was carried out with the same in-let gas at 900℃and 0.2 A/cm2. In addition,the improvement of structure and development of novel materials for increasing the electrolysis efficiency of SOECs were put forward as well.

  11. Chemical reactions of ultracold alkali dimers in the lowest-energy $^3\\Sigma$ state

    CERN Document Server

    Tomza, Michał; Moszynski, Robert; Krems, Roman V

    2013-01-01

    We show that the interaction of polar alkali dimers in the quintet spin state leads to the formation of a deeply bound reaction complex. The reaction complex can decompose adiabatically into homonuclear alkali dimers (for all molecules except KRb) and into alkali trimers (for all molecules). We show that there are no barriers for these chemical reactions. This means that all alkali dimers in the $a^3\\Sigma^+$ state are chemically unstable at ultracold temperature, and the use of an optical lattice to segregate the molecules and suppress losses may be necessary. In addition, we calculate the minimum energy path for the chemical reactions of alkali hydrides. We find that the reaction of two molecules is accelerated by a strong attraction between the alkali atoms, leading to a barrierless process that produces hydrogen atoms with large kinetic energy. We discuss the unique features of the chemical reactions of ultracold alkali dimers in the $a^3\\Sigma^+$ electronic state.

  12. The Production and Characterization of Ceramic Carbon Electrode Materials for CuCl-HCl Electrolysis

    Science.gov (United States)

    Edge, Patrick

    Current H2 gas supplies are primarily produced through steam methane reforming and other fossil fuel based processes. This lack of viable large scale and environmentally friendly H2 gas production has hindered the wide spread adoption of H2 fuel cells. A potential solution to this problem is the Cu-Cl hybrid thermochemical cycle. The cycle captures waste heat to drive two thermochemical steps creating CuCl as well as O2 gas and HCl from CuCl2 and water. The CuCl is oxidized in HCl to produce H2 gas and regenerate CuCl2, this process occurs at potentials well below those required for water electrolysis. The electrolysis process occurs in a traditional PEM fuel-cell. In the aqueous anolyte media Cu(I) will form anionic complexes such as CuCl 2 - or CuCl32-. The slow transport of these species to the anode surface limits the overall electrolysis process. To improve this transport process we have produced ceramic carbon electrode (CCE) materials through a sol-gel method incorporating a selection of amine containing silanes with increasing numbers of primary and secondary amines. When protonated these amines allow for improved transport of anionic copper complexes. The electrochemical and physical characterization of these CCE materials in a half and full-cell electrolysis environment will be presented. Electrochemical analysis was performed using cell polarization, cyclic voltammetry, and electrochemical impedance spectroscopy.

  13. Alkali metal and alkali earth metal gadolinium halide scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  14. Amount of alkali needed and variation patterns in phosphorus recovery process by struvite%鸟粪石法回收磷过程的耗碱量及其变化规律

    Institute of Scientific and Technical Information of China (English)

    张玉生; 李超群; 林金清

    2012-01-01

    Based on a theoretical analysis for every items of alkali needed in phosphorus recovery process by struvite, a formula for calculation of alkali amount needed was establishedi and used for estimating the alkali amount at different process conditions. The values calculated were compared with the experimental one measured and obtained in a double pipes/CO2 stripping packed layer phosphorus recovery pilot unit, and the results showed that average relative error between them was 18.73%, indicating that the theoritical calculation is reliable and the formula can be used for engineering estimation of alkali needed. Due to CO2 and NH3 stripping with packed layer and air, alkali amount needed saved about 20% for the double pipes/CO2 stripping packed layer phosphorus recovery unit. The alkali needed increases linearly with pH, ammonia-nitrogen/phosphorus molar ratio and the initial concentration of phosphorus. However, it should be noted that the effect of magnesium/phosphorus molar ratio was weak. The optimal operation conditions for reducing treatment costs could be as- pH 9. 20-9. 30, molar ratio of ammonia-nitrogen/ phosphorus and magnesium/phosphorus 3. 0-5. 0 and 1. 1-1. 2 respectively. Reagents consumption for phosphorus recovery process depends on initial concentration of phosphorus in wastewater and process conditions. For example, when initial concentration of phosphorus is 77. 5 mg· L-1, N : Mg " P= 5 : 1.2 : 1, pH = 9.20, alkali amount needed is 0.3315 kg and magnesium chloride containing six crystallization water is 0. 6099 kg for treating 1 ton of wastewater, the cost about ¥0. 828 and ¥ 0. 396 respectively, and ¥1. 224 as total, in which cost of alkali takes about 67. 6%.%从分析磷回收过程中的各种耗碱因素人手,推导出耗碱量的理论计算公式,计算出不同工艺条件下的理论耗碱量,并与小型套管式空气脱气填料层磷回收过程的实测值进行比较.结果表明:耗碱量的理论计算值与实验测定

  15. Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

    International Nuclear Information System (INIS)

    Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO2 from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enable the electrolyser to follow the variations in the power produced by renewables. Six plant configurations, each with a different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59-72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (∼90%) for the plants. The specific methanol costs for the six plants are in the range 11.8-25.3 Euro /GJexergy. The lowest cost is obtained by a plant using electrolysis of water, gasification of biomass and autothermal reforming of natural gas for syngas production.

  16. LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

    International Nuclear Information System (INIS)

    Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a 'hydrogen economy.' The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

  17. LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    James E. O' Brien

    2010-08-01

    Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

  18. Electrochemical reduction of CO 2 in solid oxide electrolysis cells

    Science.gov (United States)

    Zhan, Zhongliang; Zhao, Lin

    This paper describes results on the electrochemical reduction of carbon dioxide using the same device as the typical planar nickel-YSZ cermet electrode supported solid oxide fuel cells (H 2-CO 2, Ni-YSZ|YSZ|LSCF-GDC, LSCF, air). Operation in both the fuel cell and the electrolysis mode indicates that the electrodes could work reversibly for the charge transfer processes. An electrolysis current density of ≈1 A cm -2 is observed at 800 °C and 1.3 V for an inlet mixtures of 25% H 2-75% CO 2. Mass spectra measurement suggests that the nickel-YSZ cermet electrode is highly effective for reduction of CO 2 to CO. Analysis of the gas transport in the porous electrode and the adsorption/desorption process over the nickel surface indicates that the cathodic reactions are probably dominated by the reduction of steam to hydrogen, whereas carbon monoxide is mainly produced via the reverse water gas shift reaction.

  19. HYFIRE: a Tokamak - high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: a) provide high-temperature (approx. 1400 deg C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; b) provide high-temperature (approx. 700 deg to 800 deg C) heat to a thermal power cycle for generation of electricity to the HTE units; and c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constituents, H2 and O2, electrical input is required. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%. (author)

  20. Oxygen-consuming chlor alkali cell configured to minimize peroxide formation

    Science.gov (United States)

    Chlistunoff, Jerzy B.; Lipp, Ludwig; Gottesfeld, Shimshon

    2006-08-01

    Oxygen-consuming zero gap chlor-alkali cell was configured to minimize peroxide formation. The cell included an ion-exchange membrane that divided the cell into an anode chamber including an anode and a cathode chamber including an oxygen gas diffusion cathode. The cathode included a single-piece of electrically conducting graphitized carbon cloth. Catalyst and polytetrafluoroethylene were attached to only one side of the cloth. When the cathode was positioned against the cation exchange membrane with the catalyst side away from the membrane, electrolysis of sodium chloride to chlorine and caustic (sodium hydroxide) proceeded with minimal peroxide formation.

  1. Decalcification resistance of alkali-activated slag

    Energy Technology Data Exchange (ETDEWEB)

    Komljenovic, Miroslav M., E-mail: miroslav.komljenovic@imsi.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bascarevic, Zvezdana, E-mail: zvezdana@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Marjanovic, Natasa, E-mail: natasa@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Nikolic, Violeta, E-mail: violeta@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia)

    2012-09-30

    Highlights: Black-Right-Pointing-Pointer The effects of decalcification on properties of alkali-activated slag were studied. Black-Right-Pointing-Pointer Decalcification was performed by concentrated NH{sub 4}NO{sub 3} solution (accelerated test). Black-Right-Pointing-Pointer Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Black-Right-Pointing-Pointer Decalcification led to strength decrease and noticeable structural changes. Black-Right-Pointing-Pointer Alkali-activated slag showed significantly higher resistance to decalcification. - Abstract: This paper analyses the effects of decalcification in concentrated 6 M NH{sub 4}NO{sub 3} solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si {approx}0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.

  2. The 4843 Alkali Metal Storage Facility Closure Plan

    International Nuclear Information System (INIS)

    The 4843 AMSF has been used primarily to provide a centralized building to receive and store dangerous and mixed alkali metal waste, including sodium and lithium, which has been generated at the Fast Flux Test Facility and at various other Hanford Site operations that used alkali metals. Most of the dangerous and mixed alkali metal waste received consists of retired equipment from liquid sodium processes. The unit continues to store material. In general, only solid alkali metal waste that is water reactive is stored at the 4843 AMSF. The 4843 AMSF will be closed in a manner consistent with Ecology guidelines and regulations (WAC 173-303-610). The general closure procedure is detailed as follows

  3. Competitiveness of hydrogen production by High Temperature Electrolysis: Impact of the heat source and identification of key parameters to achieve low production costs

    International Nuclear Information System (INIS)

    Among the more efficient and sustainable processes that are studied for massive hydrogen production, High Temperature steam Electrolysis seems a promising process. When operating in the autothermal mode, this process does not require a high temperature source for the electrolysis reaction but only a thermal energy source able to supply enough heat to vaporize water. Using a simplified economic model, we assess the impact of the temperature, pressure and thermal energy cost of the heat source on the process competitiveness. Results show that medium temperature thermal energy sources could be coupled to the High Temperature Electrolysis process without resulting in strong overcosts. Besides, key parameters are also identified among the electrolyzer characteristics. Relevant results indicate that R and D on electrolysis cells must continue focusing on the lifespan of these equipments, for which a target lifespan of 3 years could be established.

  4. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing the...... operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...

  5. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    radiation raises the necessity to store the produced energy. Hydrogen production by water electrolysis is one of the most promising ways to do so. Alkaline electrolyzers have proven to operate reliable for decades on a large scale (up to 160 MW), but in order to become commercially attractive and compete...... and oxygen with a new type of alkaline electrolysis cell at high temperatures and pressures. To perform measurements under high pressure and at elevated temperatures it was necessary to build a measurement system around an autoclave which could stand high temperatures up to 250 °C and pressures up to...... 200 bar as well as extremely caustic environments. Based on a literature study to identify resistant materials for these conditions, Inconel 600 was selected among the metals which are available for autoclave construction. An initial single atmosphere high temperature and pressure measurement setup...

  6. Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

    Science.gov (United States)

    Khramov, A. P.; Shurov, N. I.

    2014-08-01

    Some consequences of the hypothesis of the absence of free F- ions in cryolite-alumina melts are observed. The melt at 1 < CR < 3 is assumed to consist of the complexes AlF{6/3-}, AlF{5/2-}, AlF{4/-}, Al2OF{6/2-}, and Al2O2F{4/2-}, and alkali metal cations. A formal-stoichiometric study of the processes occurring during electrolysis is performed on the basis of the accepted hypothesis. Judgments about some of the features of the electrode reactions and chemical reactions in the electrolyte volume are presented. The reaction schemes for the instances with and without the subsequent/preceding chemical reaction near the electrode or in the molten salt volume are given. The mass flows of various forms of ionic complexes through the electrolyte volume are given for these schemes. Definitive conclusions are not made in the study, but the range of possible variants for the electrochemical routes of the overall chemical reaction in the cell is limited.

  7. Electrocatalysts for medium temperature PEM water electrolysis

    OpenAIRE

    Zlotorowicz, Agnieszka

    2013-01-01

    The main subject of this PhD thesis is the fabrication and investigation the electrochemical behavior of anode catalysts appropriate for medium- temperature proton exchange membrane (PEM) water electrolysis (WE) operating in the range 100 oC through 200 oC. These catalysts were based on metal oxides, primarily IrO2 and its mixtures with some other oxides, and investigated as oxygen evolution electrocatalysts. A central research challenge in this project has been to understand the interaction ...

  8. Electrolysis activities at FCH Test Center

    DEFF Research Database (Denmark)

    Ravn Nielsen, Eva; Nygaard, Frederik Berg

    FCH Test Center for fuel cell and hydrogen technologies was established in 2010 at Risø DTU in Denmark. Today, the test center is part of DTU Energy Conversion. The center gives industry access to advanced testing and demonstration of components and systems. A number of national projects and EU p...... projects regarding water electrolysis involve FCH Test Center as a partner. This presentation gives an overview of the activities....

  9. Modeling surface nanobubbles in water electrolysis

    OpenAIRE

    Sperre, Asbjørn Hopland

    2015-01-01

    In this project a steady state approach is used to study the stability of surface nanobubbles in water electrolysis. A two dimensional domain is considered, where an electrode of length 100 nm is partly covered by a bubble. The results indicates that a single nanobubble which partially covers the electrode can be stable, as long as the electrogeneration of hydrogen is suffcient to balance the dissolution of hydrogen at near the cap of the bubble. The effect of the evaporation r...

  10. Performance and durability of solid oxide electrolysis cells

    DEFF Research Database (Denmark)

    Hauch, Anne; Jensen, Søren H; Ramousse, Severine; Mogensen, Mogens Bjerg

    2006-01-01

    Solid oxide fuel cells produced at Riso National Laboratory have been tested as electrolysis cells by applying an external voltage. Results on initial performance and durability of such reversible solid oxide cells at temperatures from 750 to 950 degrees C and current densities from -0.25 A/cm(2......) to -0.50 A/cm(2) are reported. The full cells have an initial area specific resistance as low as 0.27 Omega cm(2) for electrolysis operation at 850 degrees C. During galvanostatic long-term electrolysis tests, the cells were observed to passivate mainly during the first similar to 100 h of...... electrolysis. Cells that have been passivated during electrolysis tests can be partly activated again by operation in fuel cell mode or even at constant electrolysis conditions after several hundred hours of testing....

  11. Syngas production by high temperature steam/CO2 coelectrolysis using solid oxide electrolysis cells.

    Science.gov (United States)

    Chen, Xinbing; Guan, Chengzhi; Xiao, Guoping; Du, Xianlong; Wang, Jian-Qiang

    2015-01-01

    High temperature (HT) steam/CO2 coelectrolysis with solid oxide electrolysis cells (SOECs) using the electricity and heat generated from clean energies is an important alternative for syngas production without fossil fuel consumption and greenhouse gas emissions. Herein, reaction characteristics and the outlet syngas composition of HT steam/CO2 coelectrolysis under different operating conditions, including distinct inlet gas compositions and electrolysis current densities, are systematically studied at 800 °C using commercially available SOECs. The HT coelectrolysis process, which has comparable performance to HT steam electrolysis, is more active than the HT CO2 electrolysis process, indicating the important contribution of the reverse water-gas shift reaction in the formation of CO. The outlet syngas composition from HT steam/CO2 coelectrolysis is very sensitive to the operating conditions, indicating the feasibility of controlling the syngas composition by varying these conditions. Maximum steam and CO2 utilizations of 77% and 76% are achieved at 1.0 A cm(-2) with an inlet gas composition of 20% H2/40% steam/40% CO2. PMID:26204849

  12. Present status of r and d on hydrogen production by high temperature electrolysis of steam

    International Nuclear Information System (INIS)

    In JAERI, design and R and D works on hydrogen production process have been conducted for connecting to the HTTR under construction at the Oarai Establishment of the JAERI as the nuclear heat utilization system. As for a hydrogen production process by high-temperature electrolysis of steam, laboratory-scale experiments have been conducted using a practical electrolysis tube with 12 cells connected in series. Hydrogen was produced at a maximum density of 44 Nml/cm2h at 950degC, and know-how of operational procedures and operational experience have been also accumulated. Then, a self-supporting planar electrolysis cell was fabricated in order to improve hydrogen production performance. In the preliminary test with the planar cell, hydrogen has been produced continuously at a maximum density of 36 Nml/cm2h at lower electrolysis temperature of 850degC. This report presents typical test results mentioned above, a review of previous studies conducted in the world and R and D items required for connecting to the HTTR. (author)

  13. Petrological processes in mantle plume heads: Evidence from study of mantle xenoliths in the late Cenozoic alkali Fe-Ti basalts in Western Syria

    Science.gov (United States)

    Sharkov, Evgenii

    2015-04-01

    It is consensus now that within-plate magmatism is considered with ascending of mantle plumes and adiabatic melting of their head. At the same time composition of the plumes' matter and conditions of its adiabatic melting are unclear yet. The major source of objective information about it can be mantle xenoliths in alkali basalts and basanites which represent fragments of material of the plume heads above magma-generation zone. They are not represent material in melting zone, however, carry important information about material of modern mantle plumes, its phase composition and components, involved in melting. Populations of mantle xenoliths in basalts are characterized by surprising sameness in the world and represented by two major types: (1) dominated rocks of ``green'' series, and (2) more rare rocks of ``black'' series, which formed veins in the ``green'' series matrix. It can evidence about common composition of plume material in global scale. In other words, the both series of xenoliths represent two types of material of thermochemical mantle plumes, ascended from core-mantle boundary (Maruyama, 1994; Dobretsov et al., 2001). The same types of xenoliths are found in basalts and basanites of Western Syria (Sharkov et al., 1996). Rocks of ``green'' series are represented by Sp peridotites with cataclastic and protogranular structures and vary in composition from dominated spinel lherzolites to spinel harzburgites and rare spinel pyroxenites (websterites). It is probably evidence about incomplete homogenizing of the plume head matter, where material, underwent by partial melting, adjoins with more fertile material. Such heterogeneity was survived due to quick cooling of upper rim of the plume head in contact with relatively cold lithosphere. Essential role among xenoliths of the ``black'' series play Al-Ti-augite and water-bearing phases like hornblende (kaersutute) and Ti-phlogopite. Rocks of this series are represented by wehrlite, clinopyroxenite, amphibole

  14. Economic Analysis of Hydrogen Production by Photovoltaic Electrolysis

    OpenAIRE

    Gajardo, Luciano

    2014-01-01

    Awareness of the climate situation and greenhouse gas emissions from fossil fuels has focused attention on hydrogen as a renewable and sustainable energy resource. In this work an economic analysis of hydrogen production by a photovoltaic electrolysis system was conducted. Equations and solution methods from previous works [1, 2] have been used to compile the results. In order to run the electrolysis of water, electricity from the photovoltaic system was used. The photovoltaic electrolysis sy...

  15. Recovery of U/Pu in radiative wastes by incineration in molten sulfates and electrolysis. Application to uranium mainly

    International Nuclear Information System (INIS)

    In the process of recovery of alpha wastes a solution of wastes is obtained by pyrolysis in a molten sulfate bath at about 6000C, then, in the same bath, alpha elements are recovered by electrolysis. Here the process is applied essentially to uranium. The process was developed by Agip Nucleare and carried on by a collaboration Agip (for pyrolysis) - CEA (for electrolysis). Important reduction factors are obtained by Agip: 50 for the volume and 5 for the weight. For wastes contaminated by uranium Agip realized a pilot plant with a capacity of 1 to 2 kg of wastes per hour. A serie of experiments on Pu was conducted by Agip on a small scale. Electrolysis was investigated by the CEA with several molten sulfate baths diluted (0.5% U) or concentrated (10% U) in uranium pure or with an admixture of pyrolysis ashes. Results show that with concentrated bath (including real Agip's pyrolysates) good quality uranium oxide deposits are obtained (from U4O9 to UO2 during electrolysis). They are several millimeter thick, well crystallyzed and extraction yields reach 95 to 99%. Electrolysis is an efficient process for uranium recovery. Polarization curves and corrosion tests complete the study

  16. Fusion reactors-high temperature electrolysis (HTE)

    International Nuclear Information System (INIS)

    Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 18000C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 14000C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) [$1000/KW(E) equivalent], the H2 energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 106 scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen

  17. Microbial electrolysis cells as innovative technology for hydrogen production

    International Nuclear Information System (INIS)

    Hydrogen production is becoming increasingly important in view of using hydrogen in fuel cells. However, most of the production of hydrogen so far comes from the combustion of fossil fuels and water electrolysis. Microbial Electrolysis Cell (MEC), also known as Bioelectrochemically Assisted Microbial Reactor, is an ecologically clean, renewable and innovative technology for hydrogen production. Microbial electrolysis cells produce hydrogen mainly from waste biomass assisted by various bacteria strains. The principle of MECs and their constructional elements are reviewed and discussed. Keywords: microbial Electrolysis Cells, hydrogen production, waste biomass purification

  18. Solid Oxide Electrolysis for Oxygen Production in an ARS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon Space Development Corporation proposes an innovative, efficient and practical concept that utilizes Solid Oxide Electrolysis for regenerative air...

  19. Simple electrolyzer model development for high-temperature electrolysis system analysis using solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    An electrolyzer model for the analysis of a hydrogen production system using a solid oxide electrolysis cell has been developed, and the effects of principal parameters have been estimated via sensitivity studies based on the developed model. The main parameters considered were current density, area-specific resistance, temperature, pressure, molar fraction, and flow rates in the inlet and outlet. A simple model is also estimated for a high-temperature hydrogen production system that integrates the solid oxide electrolysis cell with a very high temperature reactor. (author)

  20. Simple Electrolyzer Model Development for High-Temperature Electrolysis System Analysis Using Solid Oxide Electrolysis Cell

    International Nuclear Information System (INIS)

    An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.

  1. Solar hydrogen by high-temperature electrolysis: Flowsheeting and experimental analysis of a tube-type receiver concept for superheated steam production

    OpenAIRE

    Houaijia, Anis; Breuer, Stefan; Thomey, Dennis; Brosig, Christian; Säck, Jan-Peter; Roeb, Martin; Sattler, Christian

    2014-01-01

    High-temperature electrolysis (HTE) offers the potential of considerably higher efficiency than conventional alkaline electrolysis when producing hydrogen from water by solar energy. The production rate of the alkaline electrolyzer process is limited since the whole energy demand is covered by electricity. By contrast, in HTE part of the energy can be introduced as high temperature heat from concentrated solar power (CSP) leading to a significantly higher process efficiency. In the interna...

  2. Efficient destruction of CF4 through in situ generation of alkali metals from heated alkali halide reducing mixtures.

    Science.gov (United States)

    Lee, Myung Churl; Choi, Wonyong

    2002-03-15

    Perfluorocarbons (PFCs) are the most potent green house gases that are very recalcitrant at destruction. An effective way of converting PFCs using hot solid reagents into safe products has been recently introduced. By investigating the thermal reductive destruction of tetrafluoromethane (CF4) we provided new insight and more physicochemical consideration on this novel process. The complete destruction of CF4was successfully achieved by flowing the gas through a heated reagent bed (400-950 degrees C) that contained powder mixtures of alkali halides, CaO, and Si. The silicon acted as a reducing agent of alkali halides for the in-situ production of alkali metals, and the calcium oxide played the role of a halide ion acceptor. The absence of any single component in this ternary mixture drastically reduced the destruction efficiency of CF4. The CF4 destruction efficiencies with the solid reagent containing the alkali halide, MX, increased in the order of Li approximately Na < K < Cs for alkali cations and I < Br < Cl < F for halide anions. This trend agreed with the endothermicity of the alkali metal generation reaction: the higher the endothermicity, the lower the destruction efficiency. Alkali metal generation was indirectly detected by monitoring H2 production from its reaction with water. The production of alkali metals increased with NaF, KF, and CsF in this order. The CsF/CaO/Si system exhibited the complete destruction of CF4 at as low as 600 degrees C. The solid product analysis by X-ray diffraction (XRD) showed the formation of CaF2 and the depletion of Si with black carbon particles formed in the solid reagent residue. No CO/CO2 and toxic HF and SiF4 formation were detected in the exhaust gas. PMID:11944694

  3. Ambient temperature cured TiB2 cathode coating for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    赖延清; 李庆余; 杨建红; 李劼

    2003-01-01

    The concept of ambient temperature curable TiB2 cathode coating was put forward, and the ambient temperature curable TiB2 cathode coating was prepared successfully. Differing from the previous TiB2 cathode coating solidified approximately at 200 ℃,the ambient temperature curable TiB2 cathode coating can be solidified at room temperature, so the heating equipment is not necessary, which simplifies the preparation process and facilitates the industrial application of TiB2 cathode coating. Many kinds of resin and curing agent were investigated. On the above-mentioned basis, the ambient temperature curable TiB2 cathode coating was prepared with furan resin 5 500 mixed with complex resins B as carbon binder and DXG1 as curing agent in 24 h. The results show that the properties of prepared coating are excellent, the electrical resistivity is 29.8 μΩ*m, the compressive strength is 33.6 MPa, which are all better than the relevant properties of partially graphitized cathode carbon block for aluminum electrolysis prescribed by the GB 8744-88. SEM morphologies show that the section morphology of the TiB2 coating is unaltered during the electrolysis test, the TiB2 coating can be used in aluminum electrolysis industry to save energy and prolong the life of aluminum electrolysis cell.

  4. Ultraviolet optical absorption of alkali cyanides and alkali halide cyanides

    International Nuclear Information System (INIS)

    The ultraviolet absorption spectra of alkali cyanide and mixed alkali halide cyanide crystals were measured at temperatures ranging from 300K down to 4.2K. A set of small absorption peaks was observed at energies near 6 eV and assigned to parity forbidden X1Σ+→a'3Σ+ transitions of the CN- molecular ions. It was observed that the peak position depends on the alkali atom while the absorption cross section strongly depends on the halogen and on the CN- concentration of the mixed crystals. These effects are explained in terms of an interaction between the triplet molecular excitons and charge transfer excitons. The experimental data were fit with a coupling energy of a few meV. The coupling mechanism is discussed and it is found to be due to the overlap between the wave functions of the two excitations. (Author)

  5. Fe-30Ni-5NiO alloy as inert anode for low-temperature aluminum electrolysis

    Science.gov (United States)

    Zhu, Yuping; He, Yedong; Wang, Deren

    2011-05-01

    Fe-30Ni-5NiO alloy anodes were prepared by a spark plasma sintering process for aluminum electrolysis. NiO nano-particles with the size of ˜20 nm were dispersed in the anodes. The oxidation behaviors of the anodes were investigated at 800°C and 850°C, respectively. The electrolysis corrosion behaviors were tested in a cryolite-alumina electrolyte at a low temperature of 800°C with anodic current densities of ˜0.5 A/cm2. The results indicated that the oxidation kinetic of the anodes followed a parabolic law. A continuous Fe2O3 film selectively formed on the surface of the anode during the electrolysis process. A semi-continuous Al2O3 layer was observed at oxide film/alloy interface, probably caused by an in-situ chemical dissolution process.

  6. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...

  7. Microscale Electrolysis Using Coin-Type Lithium Batteries and Filter

    Science.gov (United States)

    Kamata, Masahiro; Yajima, Seiko

    2013-01-01

    An educational experiment illustrates the electrolysis of water and copper chloride to middle school science students. The electrolysis cell is composed of filter paper soaked with Na[subscript 2]SO[subscript 4] or CuCl[subscript 2] aqueous solution sandwiched, along with a sheet of platinum foil, between two coin-type lithium batteries. When the…

  8. Reduction kinetics of oxide metal impurities during electrolysis of cryolite-alumina melts

    International Nuclear Information System (INIS)

    A study was made on main kinetic regularities of the process of transition of CuO, NiO, TiO2, V2O5 impurities from electrolyte to cathode metal during electrolysis of cryolite-alumina melts. It is shown that kinetics of investigated process is governed by regularities of two-stage reaction. The reduction itself can take place both at metal-electrolyte interface and in electrolyte volume

  9. Hydrogen production via urea electrolysis using a gel electrolyte

    Science.gov (United States)

    King, Rebecca L.; Botte, Gerardine G.

    2011-03-01

    A technology was demonstrated for the production of hydrogen and other valuable products (nitrogen and clean water) through the electrochemical oxidation of urea in alkaline media. In addition, this process remediates toxic nitrates and prevents gaseous ammonia emissions. Improvements to urea electrolysis were made through replacement of aqueous KOH electrolyte with a poly(acrylic acid) gel electrolyte. A small volume of poly(acrylic acid) gel electrolyte was used to accomplish the electrochemical oxidation of urea improving on the previous requirement for large amounts of aqueous potassium hydroxide. The effect of gel composition was investigated by varying polymer content and KOH concentrations within the polymer matrix in order to determine which is the most advantageous for the electrochemical oxidation of urea and production of hydrogen.

  10. Alkaline Ammonia Electrolysis on Electrodeposited Platinum for Controllable Hydrogen Production.

    Science.gov (United States)

    Gwak, Jieun; Choun, Myounghoon; Lee, Jaeyoung

    2016-02-19

    Ammonia is beginning to attract a great deal of attention as an alternative energy source carrier, because clean hydrogen can be produced through electrolytic processes without the emission of COx . In this study, we deposited various shapes of Pt catalysts under potentiostatic mode; the electrocatalytic oxidation behavior of ammonia using these catalysts was studied in alkaline media. The electrodeposited Pt was characterized by both qualitative and quantitative analysis. To discover the optimal structure and the effect of ammonia concentration, the bulk pH value, reaction temperature, and applied current of ammonia oxidation were investigated using potential sweep and galvanostatic methods. Finally, ammonia electrolysis was conducted using a zero-gap cell, producing highly pure hydrogen with an energy efficiency over 80 %. PMID:26530809

  11. Microstructural and chemical changes after high temperature electrolysis in solid oxide electrolysis cell

    Energy Technology Data Exchange (ETDEWEB)

    Mahata, Arup; Datta, Pradyot; Basu, Rajendra N., E-mail: rnbasu@cgcri.res.in

    2015-04-05

    Highlights: • Hydrogen production by running SOEC single cell. • Delamination of anode layer from the electrolyte. • Lanthanum zirconate formation due to high partial pressure of oxygen at the anode. • Formation of yttrium silicate due to diffusion of silica at the cathode side. - Abstract: Degradation of solid oxide electrolysis cell is probably the main problem in the field of high temperature steam electrolysis. In this study two anode-supported solid oxide fuel cells were tested as a solid oxide electrolysis cell operating from 875 °C to 950 °C at the applied voltage of 1.5 V and 1.7 V respectively. Microstructural and chemical changes of the cell components were studied by field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis before and after the electrolysis. FESEM analysis shows a delamination of anode layer from the electrolyte. Furthermore, formation of impurities like yttrium silicate at the cathode–electrolyte interface and lanthanum zirconate (LZ) at the anode–electrolyte interface were observed after electrolysis. It also reveals that lanthanum zicronate is formed only at the interfaces between anode functional layer La{sub 0.65}Sr{sub 0.3}MnO{sub 3−δ} (LSM)/8 mol% yttria stabilized zirconia (YSZ) and electrolyte layer (YSZ) but not at the whole anode layer. Formation of LZ is attributed to the high partial pressure of oxygen at the anode–electrolyte interface while yttrium silicate is formed due to the diffusion of silica from glass sealant into the cathode layer.

  12. Microstructural and chemical changes after high temperature electrolysis in solid oxide electrolysis cell

    International Nuclear Information System (INIS)

    Highlights: • Hydrogen production by running SOEC single cell. • Delamination of anode layer from the electrolyte. • Lanthanum zirconate formation due to high partial pressure of oxygen at the anode. • Formation of yttrium silicate due to diffusion of silica at the cathode side. - Abstract: Degradation of solid oxide electrolysis cell is probably the main problem in the field of high temperature steam electrolysis. In this study two anode-supported solid oxide fuel cells were tested as a solid oxide electrolysis cell operating from 875 °C to 950 °C at the applied voltage of 1.5 V and 1.7 V respectively. Microstructural and chemical changes of the cell components were studied by field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) analysis before and after the electrolysis. FESEM analysis shows a delamination of anode layer from the electrolyte. Furthermore, formation of impurities like yttrium silicate at the cathode–electrolyte interface and lanthanum zirconate (LZ) at the anode–electrolyte interface were observed after electrolysis. It also reveals that lanthanum zicronate is formed only at the interfaces between anode functional layer La0.65Sr0.3MnO3−δ (LSM)/8 mol% yttria stabilized zirconia (YSZ) and electrolyte layer (YSZ) but not at the whole anode layer. Formation of LZ is attributed to the high partial pressure of oxygen at the anode–electrolyte interface while yttrium silicate is formed due to the diffusion of silica from glass sealant into the cathode layer

  13. Spectroscopic Speciation of Plutonium Reduced by Electrolysis

    International Nuclear Information System (INIS)

    The oxidation state of plutonium should be carefully controlled to understand the chemical behaviors of plutonium. Pu(III) is not stable in aqueous solutions and easily oxidized in the atmosphere. In deep geological environments excluded oxygen, reducing condition is expected and will lead to rather stable Pu(III), which is very soluble compared to Pu(IV). Pu(III) ions are expected to form hydrolysis complexes in neutral and basic solutions similar to Am(III), Cm(III) and Eu(III). The reported formation constants of Pu(OH)n3-n (n=1-4) had been critically discussed, and only the first hydrolysis constant (log*β011 = -6.9 ± 0.3) was selected in a review. The main reason for the large discrepancy of the formation constants for Pu(OH)n3-n (n=2-4) is the high tendency of oxidation of Pu(III). In the present study, the reduction condition of Pu(III) was controlled by electrolysis. The electrolysis reactor was specially designed to investigate hydrolysis, colloid formation, and solubility of Pu(III) at different pHs. Pu(III) was reduced from higher oxidation states at acidic conditions, and the H+ ion concentration in solutions was simultaneously decreased without the addition of alkaline solution by electrolysis. The soluble species was investigated using spectrophotometry adopting a capillary cell (LWCC, Liquid Waveguide Capillary Cell, WPI) and the formation of plutonium colloid and solubility was determined using LIBD (Laser Induced Breakdown Detection). In this study, an electrolysis system for the reduction of plutonium and H+ ions in a solution with small volume (> 2 mL) was installed in a glove box to investigate the hydrolysis, colloid formation and solubility of Pu(III) under a reducing condition. Pu(III) was reduced from the mixed plutonium oxidation states without the generation of Pu(IV) colloidal particles or precipitates under weak acidic conditions. A coulometric titration method was applied to adjust the pH without the addition of NaOH. The change of

  14. The effects of electrolysis in electromembrane extractions

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    Grupo VLS Print Solution, 2014 - (Guzman, N.; Taveres, M.). s. 180-180 [ITP & LACE 2014. International Symposium on Electro- and Liquid Phase-Separation Techniques /21./ and Latin-American Symposium on Biotechnology, Biomedical, Biopharmaceutical, and Industrial Applications of Capillary Electrophoresis and Microchip Technology /20./. 04.10.2014-08.10.2014, Natal] R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electromembrane extractions * electrolysis * extraction performance Subject RIV: CB - Analytical Chemistry, Separation

  15. Fusion reactors for hydrogen production via electrolysis

    International Nuclear Information System (INIS)

    The decreasing availability of fossil fuels emphasizes the need to develop systems which will produce synthetic fuel to substitute for and supplement the natural supply. An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high temperature electrolysis of approx. 50 to 70% are projected for fusion reactors using high temperature blankets

  16. -Based Cermet Inert Anodes for Aluminum Electrolysis

    Science.gov (United States)

    Tian, ZhongLiang; Lai, YanQing; Li, ZhiYou; Chai, DengPeng; Li, Jie; Liu, YeXiang

    2014-11-01

    The new aluminum electrolysis technology based on inert electrodes has received much interest for several decades because of the environment and energy advantages. The key to realize this technique is the inert anode. This article presents China's recent developments of NiFe2O4-based cermet inert anodes, which include the optimization of material performance, the joint between the cermet inert anode and metallic bar, as well as the results of 20 kA pilot testing for a large-size inert anode group. The problems NiFe2O4-based cermet inert anodes face are also discussed.

  17. Theoretical and experimental investigation of cappillary electrolysis system

    International Nuclear Information System (INIS)

    In a fusion reactor environment, it is expected that highly tritiated water will be formed when tritium is extracted from the blanket as well as during the plasma exhaust purification process. As a consequence, the recovery of elemental tritium from its oxides is an essentrial step before recycling the fuel to the reactor. Among different basic processes that can be used for this purpose, electrolysis appears to be very promising. Therefore, SCK/CEN has developed a small dedicated cell designed to decompose 100 ml/day of pure DTO or HTO. At the present project stage, a prototype cell is available and the device has been successfully tested with light water during several thousands of hours. In the orginal concept, the liquid inventory is limited to the vertical porous gas separator. Capillarity is used as a driving force to feed the cell to avoid the use of a pump. This fact turns out to have a considerable influence on the behaviour of the electrolytic system. This particular behaviour has been theorectically investigated with the aim to allow a better basic understanding of the capillary electrolysis. A deterministic model has been developed for its purpose. The mathematical equations show clearly that the electrolyte tends to accumulate at the top of the gas separator. An equilibrium state can be reached only if sufficiently large amounts of electrolyte can flow back towards the bottom of the gas separator. This counter-flow has been taken into account by introducing a single general diffusion coefficient into the model. In a second phase, systematic experimental runs have been carried out with mock-up cells. A statistical treatment based on the maximum likelihood estimation algorithm allowed to compute the best values for the diffusion coefficient and to validate the model. Finally, acceptabel ranges of the independent varialbles have been defined and all the subsequent experimental runs have been performed without stability problems. (author). 12 refs.; 5 figs

  18. Degradation in Solid Oxide Cells During High Temperature Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Manohar Sohal

    2009-05-01

    Idaho National Laboratory has an ongoing project to generate hydrogen from steam using solid oxide electrolysis cells. One goal of that project is to address the technical and degradation issues associated with solid oxide electrolysis cells. This report covers a variety of these degradation issues, which were discussed during a workshop on “Degradation in Solid Oxide Electrolysis Cells and Strategies for its Mitigation,” held in Phoenix, AZ on October 27, 2008. Three major degradation issues related to solid oxide electrolysis cells discussed at the workshop are: • Delamination of O2-electrode and bond layer on steam/O2-electrode side • Contaminants (Ni, Cr, Si, etc.) on reaction sites (triple-phase boundary) • Loss of electrical/ionic conductivity of electrolyte. This list is not all inclusive, but the workshop summary can be useful in providing a direction for future research related to the degradation of solid oxide electrolysis cells.

  19. 环己酮生产中皂化废碱液处理新工艺%A Novel Treatment Process of the Saponification Waste Alkali Liquor in Cyclohexanone Production

    Institute of Scientific and Technical Information of China (English)

    刘文岗; 陈志斌

    2012-01-01

    This paper presents a novel treatment process.chemical method,which utilizes comprehensively the saponification waste alkali liquor in cyclohexanone production.The treatments of waste water,waste gas and waste solid generated during the treating process are introduced as well.As compared with burning method,the existing industrial process,the chemical method is better both in economy and in environment-protecting and is worth to be applied widely,for it has less investment,pollution degree and operation cost with recovery of the valuable products.%介绍了一种综合利用环己酮生产中皂化废碱液的新工艺(化学法)及其处理过程中废水、废气及废渣的处理方法,与现有工业处理方法(焚烧法)相比,该方法投资省、污染小、运营费用低、回收物价值高,无论在经济方面还是在环保方面,均具有明显优势,值得推广.同时,指出了需要完善和改进的地方.

  20. Studying the processes of sulphates and chlorides extraction from water at low-waste water demineralization technology

    Directory of Open Access Journals (Sweden)

    Inna M. Тrus

    2014-12-01

    Full Text Available To solve the disposal problem of high-salinity liquid wastes resulting from the water demineralization, researched are the processes of chlorides’ and sulphates’ ion-exchange separation with further sulphates (in the form of calcium sulphate removal from the technological cycle. It is shown that the desulphatized water can be effectively desalinated by reverse osmosis filters, including low-pressure membranes Filmtec TW30-1812-50. The liquid waste obtained in form of concentrates, does contain chlorides, sodium ions and hardness ions. Established is that at these concentrates processing by lime and sodium carbonate or alkali and sodium carbonate they are softened with hardness decrease up to 0,25…0,95 mg-eq/dm3, which allows these solutions’ further electrolysis to obtain alkali and hydrochloric acid. Through direct electrolysis of concentrates, obtained by reverse osmosis water desalination at anionic membrane two-chamber electrolysers, we obtained a disinfectant solution containing chlorine oxigenates (active chlorine, hypochlorite, chlorite and sodium chlorate and duly effective in water sterilization. The resulting solution well keeps its properties and is promising for disinfection of natural and waste waters.

  1. Effect of Alkali Stress on Soluble Sugar, Antioxidant Enzymes and Yield of Oat

    Institute of Scientific and Technical Information of China (English)

    BAI Jian-hui; LIU Jing-hui; ZHANG Na; YANG Jun-heng; SA Ru-la; WU Lan

    2013-01-01

    Alkali stress can cause severe crop damage and reduce production. However, physiological processes involved in alkali stress in oat seedlings are not well understood. In this study, physiological responses and yield of oat to alkali stress were studied using the alkali-tolerant oat genotype Vao-9 and the alkali-sensitive oat genotype Baiyan 5. The results were:(i) low concentrations of alkali stress (25 and 50 mmol L-1) significantly reduced the yield and grain weight while increased the oat grain number per spike. A negative correlation between yield and malondialdehyde (MDA) content at the jointing and grain filling stages and positive correlations between yield on one hand and superoxide dismutase (SOD), and peroxidase (POD) activities on the other at the jointing stage were observed. There was a positive correlation between MDA and soluble sugar at the grain filling stage;(ii) soluble sugar content was increased at the jointing and grain filling stages and decreased at the heading stage by alkali stress;(iii) alkali stress increased the SOD activity during the heading and grain filling stages, and increased the POD activity at the heading stage. As compared to the control, the increase of MDA contents in alkali-treated oat was observed, during the jointing, heading and grain filling stages;(iv) under alkali stress, the oat genotype Vao-9 showed higher antioxidant enzyme activity and lower soluble sugar contents during the heading stage, and lower MDA contents than those in the oat genotype Baiyan 5 under alkali stress. The result suggested that the high ROS scavenging capacity and soluble sugar levels might play roles in oat response to alkali stress.

  2. Construction of thermionic alkali-ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Ul Haq, F.

    1986-04-01

    A simple technique is described by which singly charged alkali ions of K, Na, Li, Rb and Cs are produced by heating ultra-pure chemical salts of different alkali metals on tungsten filaments without employing a temperature measuring device. The character of alkali-ion currents at different heating powers and the remarkably constant ion emission current for prolonged periods are discussed.

  3. Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

    Science.gov (United States)

    Joshi, Ashok V.; Balagopal, Shekar; Pendelton, Justin

    2011-12-13

    Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

  4. Alkali and transition metal phospholides

    International Nuclear Information System (INIS)

    Major tendencies in modern chemistry of alkali and transition metal phospholides (phosphacyclopentadienides) are systematized, analyzed and generalized. Basic methods of synthesis of these compounds are presented. Their chemical properties are considered with a special focus on their complexing ability. Potential applications of phospholides and their derivatives are discussed. The bibliography includes 184 references

  5. Inhibition of the maillard reaction in the process of making rice bran protein by alkali method%碱法制取米糠蛋白过程中美拉德反应的抑制

    Institute of Scientific and Technical Information of China (English)

    王雪; 于鹏; 周雪松; 张智; 于殿宇

    2013-01-01

    应用葡萄糖氧化酶(GOD)对米糠中的葡萄糖进行氧化抑制,通过单因素实验,考察了酶解过程中反应温度、pH、反应时间、GOD添加量对蛋白色素抑制率的影响,并在单因素水平的基础上进行响应面优化实验,确定了反应的最佳条件:反应温度45℃,pH5.5,反应时间25min,GOD添加量0.035%,在优化出的最佳条件下进行反应,得到的蛋白色素抑制率为62.73%,说明向米糠中添加GOD可有效改善碱提酸沉法提取米糠蛋白后的色泽,提高蛋白的色素抑制率.%The purpose of the present study was to optimize the process of making rice bran protein by alkali method using single-factor tests and response surface methodology,glucose oxidase was used to inhibit the oxidation of glucose in the rice bran.The effect of reaction temperature,pH,reaction time,the GOD addition amount on the protein pigment inhibition rate in the enzymatic process was investigated,and on the basis of the single-factor test,the optimum conditions of reaction was determined by response surface methodology.The reaction temperature was 45℃,the reaction pH was 5.5,the reaction time was 25min,the addition amount of GOD was 0.035%.The pigment inhibition rate reached to 62.73% on the optimum conditions.Results indicated that this method could improve the color after extraction of rice bran protein by alkali extraction and acid precipitation,and increase protein pigment inhibition rate effectually.

  6. Alkaline and high-temperature electrolysis for nuclear hydrogen production

    International Nuclear Information System (INIS)

    In anticipation to energy world evolution in the coming decades, we will discuss the role that hydrogen can play in the future energy systems. Facing strong energy demand growth in the transport field, expected oil production limitation and climate change constraints, the oil industry has to raise difficult challenges requiring short-term actions. Hydrogen being a key molecule for this industry, we will show how nuclear produced hydrogen can contribute to resolve some of the oil industry challenges, within a compatible time frame with the inertia of climate mechanisms. Technical solutions to produce hydrogen using nuclear energy and electrolysis will then be described. We will describe the relevant characteristics of alkaline electrolyser technology. Using results of nuclear-aided petrochemical processes technico-economic studies, we will show that synthetic fuels are accessible at reasonable costs. We will also discuss the limitations of these technological solutions and describe which improvements and evolutions can be expected and looked for, as regards both the nuclear industry and electrolyser technologies. For the latter, we will discuss both alkaline and high-temperature electrolysis. The evolutions to be looked for should minimise development efforts, therefore we will argue why advanced thermal integration should be studied in order to avoid too-stringent requirements on both the nuclear reactor and the electrolyser. Remaining challenges will be discussed. As a result, our paper will show how and why the nuclear industry, and specifically AREVA, will be able with relatively limited developments to massively de-carbonise transportation from well to wheel, through a variety of applications. (authors)

  7. Pathways of birnessite formation in alkali medium

    Institute of Scientific and Technical Information of China (English)

    FENG Xionghan; TAN Wenfeng; LIU Fan; HUANG Qiaoyun; LIU Xiangwen

    2005-01-01

    Birnessite is a common weathering and oxidation product of manganese-bearing rocks. An O2 oxidation procedure of Mn(OH)2 in the alkali medium has been used to synthesize birnessite. Fast and powder X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), energy dispersed X-ray analysis (EDAX), infrared spectroscopy (IR) techniques and chemical composition analysis, Eh-pH equilibrium diagram approaches were employed to investigate the reaction process and pathways of birnessite formation. Results showed that the process of the birnessite formation could be divided into four stages: (1) formation stage for hausmannite and feitknechtite, (2) stage of transformation of hausmannite and feitknechtite to buserite, (3) buserite crystal growing stage, and (4) stage of conversion of buserite into birnessite. Mn(OH)2 was mainly present as amorphous state only for a short initial time of oxidation reaction. In the oxidation process, buserite formed following two pathways by recrystallization after dissolution of the intermediates, and the transformations of the minerals depended on the Eh determined by the dissolved O2 concentration on their surfaces. The results are fundamental in further exploration on the mechanism of birnessite formation in the alkali medium. A great practical significance would also be expected with respect to the areas of material sciences.

  8. Systems Engineering Provides Successful High Temperature Steam Electrolysis Project

    Energy Technology Data Exchange (ETDEWEB)

    Charles V. Park; Emmanuel Ohene Opare, Jr.

    2011-06-01

    This paper describes two Systems Engineering Studies completed at the Idaho National Laboratory (INL) to support development of the High Temperature Stream Electrolysis (HTSE) process. HTSE produces hydrogen from water using nuclear power and was selected by the Department of Energy (DOE) for integration with the Next Generation Nuclear Plant (NGNP). The first study was a reliability, availability and maintainability (RAM) analysis to identify critical areas for technology development based on available information regarding expected component performance. An HTSE process baseline flowsheet at commercial scale was used as a basis. The NGNP project also established a process and capability to perform future RAM analyses. The analysis identified which components had the greatest impact on HTSE process availability and indicated that the HTSE process could achieve over 90% availability. The second study developed a series of life-cycle cost estimates for the various scale-ups required to demonstrate the HTSE process. Both studies were useful in identifying near- and long-term efforts necessary for successful HTSE process deployment. The size of demonstrations to support scale-up was refined, which is essential to estimate near- and long-term cost and schedule. The life-cycle funding profile, with high-level allocations, was identified as the program transitions from experiment scale R&D to engineering scale demonstration.

  9. Durable SOC stacks for production of hydrogen and synthesis gas by high temperature electrolysis

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Høgh, Jens Valdemar Thorvald; Nielsen, Karsten Agersted;

    2011-01-01

    Electrolysis of steam and co-electrolysis of steam and carbon dioxide was studied in Solid Oxide Electrolysis Cell (SOEC) stacks composed of Ni/YSZ electrode supported SOECs. The results of this study show that long-term electrolysis is feasible without notable degradation in these SOEC stacks. T...

  10. Preparation of Al(OH)3 by ion membrane electrolysis and precipitation of sodium aluminate solution with seeds

    Institute of Scientific and Technical Information of China (English)

    LI Yuan-gao; CHEN Qi-yuan; WANG Song-sen; YIN Zhou-lan; ZHANG Ping-min

    2008-01-01

    The preparation of Al(OH)3 by the ion exchange membrane electrolysis followed by the precipitation of sodium aluminate solution with seeds was made. During the process of ion membrane electrolysis, the sodium aluminate solution is rapidly acidified and the caustic ratio (aK) is decreased due to oxygen evolution in the anodic region. And the causticity of solution is increased due to hydrogen evolution in the cathode region, producing the high concentration of caustic soda solution. Regulating the acidity of the anodic solution by controlling the electric quantity in the electrolysis and subsequent decomposing the solution, Al(OH)3 could yield with very large rate and high efficiency. The experiments also indicate that the quality of aluminum hydroxide product is greatly affected by the impurity silicon.

  11. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis

    International Nuclear Information System (INIS)

    Elemental analyses of palladium electrodes were conducted after a new type of light water electrolysis was performed at optimum conditions in a system designed to induce a nuclear reaction. This process is referred to as Pd/Pd light water critical electrolysis. The conjecture that a nuclear transmutation process is occurring in this experiment is easier to test in this system, because it is easy to determine whether the elements detected on the cathode surface are impurities or transmutation products. We assume that the elements detected only on the cathode surface, and nowhere else in the cell as contamination, namely iron, titanium, chromium and so on, must be transmutation products. Furthermore, countless Ohmori-type palladium craters were observed for the first time for this system, and these are evidence that nuclear reactions occurred at the electrode surface. (author)

  12. Structural Investigation of Alkali Activated Clay Minerals for Application in Water Treatment Systems

    Science.gov (United States)

    Bumanis, G.; Bajare, D.; Dembovska, L.

    2015-11-01

    Alkali activation technology can be applied for a wide range of alumo-silicates to produce innovative materials with various areas of application. Most researches focuse on the application of alumo-silicate materials in building industry as cement binder replacement to produce mortar and concrete [1]. However, alkali activation technology offers high potential also in biotechnologies [2]. In the processes where certain pH level, especially alkaline environment, must be ensured, alkali activated materials can be applied. One of such fields is water treatment systems where high level pH (up to pH 10.5) ensures efficient removal of water pollutants such as manganese [3]. Previous investigations had shown that alkali activation technology can be applied to calcined clay powder and aluminium scrap recycling waste as a foam forming agent to create porous alkali activated materials. This investigation focuses on the structural investigation of calcined kaolin and illite clay alkali activation processes. Chemical and mineralogical composition of both clays were determined and structural investigation of alkali activated materials was made by using XRD, DTA, FTIR analysis; the microstructure of hardened specimens was observed by SEM. Physical properties of the obtained material were determined. Investigation indicates the essential role of chemical composition of the clay used in the alkali activation process, and potential use of the obtained material in water treatment systems.

  13. Preparation of Al-Si-Ti Master Alloys by Electrolysis of Silica and Titania in Cryolite-Alumina Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aluminum-silicon-titanium master alloys were prepared in the laboratory by electrolysis of silica and titania dissolved in cryolite-alumina melts. Alloys containing up to 12 mass% Si and 2.6 mass% Ti were formed after about 90 min of electrolysis at 950℃. The current efficiency for the preparation of the Al-Si-Ti alloys varied with time, temperature and cathodic current density. It is concluded that this electrolytic method may be an interesting alternative to the direct metal mixing process for formation of Al-Si-Ti master alloys.

  14. Microbial electrolysis cells for production of methane from CO2: long-term performance and perspectives

    OpenAIRE

    Eerten-Jansen, van, M.C.A.A.; Heijne, ter, A.; C J N Buisman; Hamelers, H.V.M.

    2012-01-01

    A methane-producing microbial electrolysis cell (MEC) is a technology to convert CO2 into methane, using electricity as an energy source and microorganisms as the catalyst. A methane-producing MEC provides the possibility to increase the fuel yield per hectare of land area, when the CO2 produced in biofuel production processes is converted to additional fuel methane. Besides increasing fuel yield per hectare of land area, this also results in more efficient use of land area, water, and nutrie...

  15. A Study on the Preparation of Regular Multiple Micro-Electrolysis Filler and the Application in Pretreatment of Oil Refinery Wastewater.

    Science.gov (United States)

    Yang, Ruihong; Zhu, Jianzhong; Li, Yingliu; Zhang, Hui

    2016-01-01

    Through a variety of material screening experiments, Al was selected as the added metal and constituted a multiple micro-electrolysis system of Fe/C/Al. The metal proportion of alloy-structured filler was also analyzed with the best Fe/C/Al ratio of 3:1:1. The regular Fe/C/Al multiple micro-electrolysis fillers were prepared using a high-temperature anaerobic roasting method. The optimum conditions for oil refinery wastewater treated by Fe/C/Al multiple micro-electrolysis were determined to be an initial pH value of 3, reaction time of 80 min, and 0.05 mol/L Na₂SO₄ additive concentration. The reaction mechanism of the treatment of oil refinery wastewater by Fe/C/Al micro-electrolysis was investigated. The process of the treatment of oil refinery wastewater with multiple micro-electrolysis conforms to the third-order reaction kinetics. The gas chromatography-mass spectrometry (GC-MS) used to analyze the organic compounds of the oil refinery wastewater before and after treatment and the Ultraviolet-visible spectroscopy (UV-VIS) absorption spectrum analyzed the degradation process of organic compounds in oil refinery wastewater. The treatment effect of Fe/C/Al multiple micro-electrolysis was examined in the continuous experiment under the optimum conditions, which showed high organic compound removal and stable treatment efficiency. PMID:27136574

  16. A Study on the Preparation of Regular Multiple Micro-Electrolysis Filler and the Application in Pretreatment of Oil Refinery Wastewater

    Directory of Open Access Journals (Sweden)

    Ruihong Yang

    2016-04-01

    Full Text Available Through a variety of material screening experiments, Al was selected as the added metal and constituted a multiple micro-electrolysis system of Fe/C/Al. The metal proportion of alloy-structured filler was also analyzed with the best Fe/C/Al ratio of 3:1:1. The regular Fe/C/Al multiple micro-electrolysis fillers were prepared using a high-temperature anaerobic roasting method. The optimum conditions for oil refinery wastewater treated by Fe/C/Al multiple micro-electrolysis were determined to be an initial pH value of 3, reaction time of 80 min, and 0.05 mol/L Na2SO4 additive concentration. The reaction mechanism of the treatment of oil refinery wastewater by Fe/C/Al micro-electrolysis was investigated. The process of the treatment of oil refinery wastewater with multiple micro-electrolysis conforms to the third-order reaction kinetics. The gas chromatography–mass spectrometry (GC–MS used to analyze the organic compounds of the oil refinery wastewater before and after treatment and the Ultraviolet–visible spectroscopy (UV–VIS absorption spectrum analyzed the degradation process of organic compounds in oil refinery wastewater. The treatment effect of Fe/C/Al multiple micro-electrolysis was examined in the continuous experiment under the optimum conditions, which showed high organic compound removal and stable treatment efficiency.

  17. LIQUID BIO-FUEL PRODUCTION FROM NON-FOOD BIOMASS VIA HIGH TEMPERATURE STEAM ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    G. L. Hawkes; J. E. O' Brien; M. G. McKellar

    2011-11-01

    Bio-Syntrolysis is a hybrid energy process that enables production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), bio-syntrolysis has the potential to provide a significant alternative petroleum source that could reduce US dependence on imported oil. Combining hydrogen from HTSE with CO from an oxygen-blown biomass gasifier yields syngas to be used as a feedstock for synthesis of liquid transportation fuels via a Fischer-Tropsch process. Conversion of syngas to liquid hydrocarbon fuels, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power

  18. Investigation of solid surfaces by nuclear spin polarized alkali atoms

    International Nuclear Information System (INIS)

    Nuclear spin polarized alkali atom beams are used to investigate metal surfaces. The surface diffusion of the alkali atoms on the surface results in a randomly fluctuating electric field gradient. The relaxation is measured in dependence of the surface temperature. Using an additional external RF field, also NMR measurement can be performed. Besides some fluctuating components of the EFG which cause the relaxation process, there is also a static part of the EFG. This results in an energy splitting of the nuclear spin states and can be detected by the NMR experiments. (Auth.)

  19. Electron Mean-Free Paths in the Alkali Metals

    OpenAIRE

    Wertheim, G.K.; Riffe, D. Mark; Smith, N.V.; Citrin, P. H.

    1992-01-01

    Photoemission data in which the signal from the first atomic layer is well resolved from that of the bulk are used to determine accurately the kinetic-energy dependence of the inelastic-electron mean free path in the alkali metals. At the higher kinetic energies, the data are in very good agreement with the theory of Penn. Below about 10 eV, the mean free path in the heavier alkali metals drops markedly below the theoretical values. This is attributed to electron decay processes involvi...

  20. Status of the INL high-temperature electrolysis research programme - experimental and modelling

    International Nuclear Information System (INIS)

    This paper provides a status update on the high-temperature electrolysis (HTE) research and development programme at Idaho National Laboratory (INL), with an overview of recent large-scale system modelling results and the status of the experimental programme. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyser module. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor coolant outlet temperatures. In terms of experimental research, the INL has recently completed an Integrated Laboratory Scale (ILS) HTE test at the 15 kW level. The initial hydrogen production rate for the ILS test was in excess of 5000 litres per hour. Details of the ILS design and operation will be presented. Current small-scale experimental research is focused on improving the degradation characteristics of the electrolysis cells and stacks. Small-scale testing ranges from single cells to multiple-cell stacks. The INL is currently in the process of testing several state-of-the-art anode-supported cells and is working to broaden its relationship with industry in order to improve the long-term performance of the cells. (authors)

  1. Status of the INL high-temperature electrolysis research program –experimental and modeling

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots; M. G. McKellar; E. A. Harvego; K. G. Condie; G. K. Housley; J. S. Herring; J. J. Hartvigsen

    2009-04-01

    This paper provides a status update on the high-temperature electrolysis (HTE) research and development program at the Idaho National Laboratory (INL), with an overview of recent large-scale system modeling results and the status of the experimental program. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor coolant outlet temperatures. In terms of experimental research, the INL has recently completed an Integrated Laboratory Scale (ILS) HTE test at the 15 kW level. The initial hydrogen production rate for the ILS test was in excess of 5000 liters per hour. Details of the ILS design and operation will be presented. Current small-scale experimental research is focused on improving the degradation characteristics of the electrolysis cells and stacks. Small-scale testing ranges from single cells to multiple-cell stacks. The INL is currently in the process of testing several state-of-the-art anode-supported cells and is working to broaden its relationship with industry in order to improve the long-term performance of the cells.

  2. Behaviour of gaseous alkali compounds in coal gasification; Kaasumaisten alkaliyhdisteiden kaeyttaeytyminen kivihiilien kaasutuksessa

    Energy Technology Data Exchange (ETDEWEB)

    Nykaenen, J. [Imatran Voima Oy, Vantaa (Finland)

    1997-10-01

    In this project the behaviour of alkali compounds emitting from CO{sub 2}/O{sub 2}- and airblown gasification are studied. This research project is closely connected to an EU-project coordinated by the Delft University of Technology (DUT). In that project alkali emissions from a 1.6 MW pilot plant will be measured. The results from those measurements will be compared with the calculations performed in this LIEKKI 2 project. The equilibrium calculations show that the major gaseous alkali compounds emitting from combustion and gasification are chlorides and hydroxides. This applies both to air- and CO{sub 2}/O{sub 2}-blown processes. In all the cases studied the concentration of gaseous alkali compounds is determined mainly by the amount of chlorides. The key parameters, with respect to alkali behaviour, are the temperature of the process and chlorine content of the coal. By cooling the gases down to 600 deg C prior to a ceramic filter the alkali concentration can be kept about at 100 ppbv. In combustion, the addition of calcium carbonate increases the amount of gaseous alkali compounds by decreasing the amount of alkali sulphates. In the case of gasification the importance of limestone is negligible. The difference between air- and CO{sub 2}/O{sub 2}-blown processes, in terms of gaseous alkali emissions, is small. This is because CO{sub 2} concentration of the gas does not have a strong impact on alkali chlorides. Furthermore, the effect of CO{sub 2}/O{sub 2}-ratio of the recirculation process is negligible. (orig.)

  3. Electrocatalysis of carbon anode in aluminium electrolysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The anodic overvoltage of the carbon anode in aluminum electrolysis isof the order of 0.6 V at normal current densities. However, it can be reduced somewhat by doping the anode carbon with various inorganic compounds. A new apparatus was designed to improve the precision of overvoltage measurements. Anodes were doped with MgAl2O4 and AlF3 both by impregnation of the coke and by adding powder, and the measured overvoltage was compared with that of undoped samples. For prebake type anodes baked at around 1150 oC, the anodic overvoltage was reduced by 40-60 mV, and for Soderberg type anodes, baked at 950 oC, by 60-80 mV.

  4. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...... overpotentials. Current densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2.3 A cm-2 were obtained....

  5. HIGH-TEMPERATURE ELECTROLYSIS FOR LARGE-SCALE HYDROGEN AND SYNGAS PRODUCTION FROM NUCLEAR ENERGY – SYSTEM SIMULATION AND ECONOMICS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; M. G. McKellar; E. A. Harvego; C. M. Stoots

    2009-05-01

    A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures. Pure steam electrolysis for hydrogen production as well as coelectrolysis for syngas production from steam/carbon dioxide mixtures have both been considered. In addition, the feasibility of coupling the high-temperature electrolysis process to biomass and coal-based synthetic fuels production has been considered. These simulations demonstrate that the addition of supplementary nuclear hydrogen to synthetic fuels production from any carbon source minimizes emissions of carbon dioxide during the production process.

  6. Pulse-step-change electrolysis at obtaining of zinc-scandium alloys from chloride-fluoride melts

    International Nuclear Information System (INIS)

    The results of laboratory studies and pilot production tests are reported for the process of electrolyte deposition of scandium on liquid zinc from chloride-fluoride melts under pulse-step conditions with the aim of producing alloys with a maximum possible scandium content. The ranges of optimum parameters and electrolysis methods permitting the solution of the problem are determined

  7. Solid oxide electrolysis cell analysis by means of electrochemical impedance spectroscopy: A review

    Science.gov (United States)

    Nechache, A.; Cassir, M.; Ringuedé, A.

    2014-07-01

    High temperature water electrolysis based on Solid Oxide Electrolysis Cell (SOEC) is a very promising solution to produce directly pure hydrogen. However, degradation issues occurring during operation still represent a scientific and technological barrier in view of its development at an industrial scale. Electrochemical Impedance Spectroscopy (EIS) is a powerful in-situ fundamental tool adapted to the study of SOEC systems. Hence, after a quick presentation of EIS principle and data analysis methods, this review demonstrates how EIS can be used: (i) to characterize the performance and mechanisms of SOEC electrodes; (ii) as a complementary tool to study SOEC degradation processes for different cell configurations, in addition to post-test tools such as scanning electron microscopy (SEM) or X-ray diffraction (XRD). The use of EIS to establish a systematic SOEC analysis is introduced as well.

  8. Organic Fuel Synthesis from Atmospheric Carbon Dioxide and Hydrogen Produced from Water by Electrolysis

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2009-01-01

    Synthesis of organic fuels from cain dioxide and hydrogen is analysed, in terms of energy recovery efficiency, and the required energy input for electrolysis of water. This electrical energy is related to the thermal energy required in a power station. A method is described to recover heat from energy-producing reactions in the fuel synthesis process, which can then be used to reduce the electrical energy requirement for electrolysis. By co-locating the fuel synthesis plant with a thermal power station, primary (thermal) energy can be used to produce high temperature steam, with a lower electrical requirement for electrolytic production of hydrogen. This can make more efficient use of the primary energy than a thermodynamic engine. Comparison is made with alternative fuels, in terms of energy budget, sustainability, carbon dioxide emissions, etc. The energy security benefits of advanced fuel synthesis are also identified.

  9. A study of metallic coatings obtained by electrolysis of molten salts

    International Nuclear Information System (INIS)

    An appropriate technique has been developed for obtaining compact metallic coatings from electrolysis of molten salts. Through the use of this method, it has been possible to produce pure metal deposits which, until now, has been extremely difficult to do. The apparatus used and the main steps of the process such as dehydration of the solvant, degassing of the equipment, and starting of the electrolytic process, are first described. This is followed by a discussion of the deposits of the metals beryllium, uranium, tantalum and tungsten obtained from electrolysis of molten fluorides at temperatures between 600 and 8000C. The metal coatings so obtained are homogeneous and show continuity, their thicknesses varying from a few microns to a millimeter or more. They have been studied by measurements. As potential applications of this new technique, one can mention the growth of diffusion barriers and the production of cathodes for thermoionic emission. The method can also be used for electroforming. An intermetallic diffusion between the deposit and the substrate has been observed in some cases. The advantage of the technique of melt electrolysis in obtaining metal coatings of enhanced thicknesses is illustrated by taking the beryllium-nickel system as an example. It is shown that the thickness obtained is proportional to the square root of growth time and is about 6 to 8 times larger than that obtained by conventional techniques

  10. On-line alkali monitoring - Part 1

    International Nuclear Information System (INIS)

    As a consequence of the increased knowledge of the environmental impact of combustion based heat and power generation, the use of renewable biofuels will be increased. An obstacle associated to biofuel combustion compared to other fuels is the large release of alkali. Alkali compounds in flue gases are known to cause severe operational problems. Three of the major problems are; fouling of superheating tubes (causing reduced heat transfer and possibly corrosion), agglomeration of the bed material in fluidized beds, and poisoning of SCR catalysts. Yet another alkali related problem arises when, in order to increase the electric efficiency of combustion power plants, combined-cycle technology is used. Alkali vapour present in the fuel gas for the gas turbine is condensed to particles which increase corrosion and erosion of the turbine blades. The research on ash related operational problems has to be extended in order to ensure future use of biofuels in heat and power generation. In all successful research, adequate tools are necessary. To investigate ash related problems the key issue is to be able to perform continuous alkali measurements. This pilot study has investigated the need of continuous alkali measurements, which alkali species are harmful in the different applications and also available instrumentation capable of measuring the specific alkali species. The report gives a short summary presenting alkali related operational problems. In addition a schematic overview is given, showing the alkali species that possibly can exist in various parts of the power plant. 48 refs, 13 figs, 4 tabs

  11. Solar Power Augmented Electrolysis Module for Energy Storage Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Regenerative fuel cell systems often include a dedicated electrolysis module with solar photovoltaic (PV) panels packaged as a subsystem of the larger energy...

  12. Durability of Solid Oxide Electrolysis Cells for Syngas Production

    DEFF Research Database (Denmark)

    Sun, Xiufu; Chen, Ming; Liu, Yi-Lin; Hjalmarsson, Per; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard; Mogensen, Mogens Bjerg; Hendriksen, Peter Vang

    2013-01-01

    Performance and durability of Ni-YSZ supported solid oxide electrolysis cells (SOECs) for co-electrolysis of H2O and CO2 at high current density was investigated. The cells consist of a Ni-YSZ support, a Ni-YSZ electrode, a YSZ electrolyte, and an LSM-YSZ electrode. The durability was examined at...... 800°C and electrolysis current densities of −1 or −1.5 A/cm2 with 60% reactant (H2O + CO2) utilization. The cell voltage degradation showed a strong dependence on the electrolysis current density. Electrochemical characterization of the cells showed that the degradation was mainly related to the LSM...

  13. The micro-electrolysis technique in waste water treatment

    International Nuclear Information System (INIS)

    The micro-electrolysis is one of the efficient methods to treat some kinds of waste water. The experiments have shown its high efficiency in sewage treatment and some kinds of industrial waste water. It is suitable for pre-treatment of high concentrated waste water and deep treatment of waste water for reuse purpose. The disadvantage of micro-electrolysis is its high energy consumption in case of high electrolyte concentration. (author) 2 figs., 11 tabs., 2 refs

  14. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation

    OpenAIRE

    Stehling, Michael K.; Guenther, Enric; Mikus, Paul; Klein, Nina; Rubinsky, Liel; Rubinsky, Boris

    2016-01-01

    Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs “Synergistic electrolysis and electroporation” (SEE). The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to es...

  15. Effects of H2S and process conditions in the synthesis of mixed alcohols from syngas over alkali promoted cobalt-molybdenum sulfide

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Mortensen, Peter Mølgaard; Trane, Rasmus;

    2009-01-01

    The present work is an investigation of how the process conditions influence the synthesis of mixed alcohols from syngas over a K2CO3/Co/MoS2/C catalyst. The emphasis in the investigations is upon the effects of H2S in the syngas feed. However the effects of the temperature and of the partial...... stabilization of the product distribution and ensures that higher alcohols are the dominant reaction products. With less than 57 ppmv H2S in the feed the stabilization of the product distribution is much slower, and methanol is the dominant product. An investigation of the reaction kinetics indicates a high CO...

  16. Utilization of coal-derived pyrite by electrolysis

    Institute of Scientific and Technical Information of China (English)

    李登新; M.Makinot; 高晋生; 孟繁玲

    2001-01-01

    The utilization of coal-derived pyrite by electrolysis was studied. It is obvious that the sulfur and Fe in pyrite can be electrolyzed into Fe3+ and SO2-4, and the no pollutant is drained off. In this paper, the influence of conditions, including electrolysis potential, time, temperature, the acidity of electrolysis solutions, the concentration of adding agent, the concentration of pyrite, and the rate of conversion of pyrite (Cr) was investigated. Cr increases with the rise of potential, time, temperature, acidity and the concentration of additive agent, but decreases, with the rise of concentration of pyrite. At the certain conditions (at the potential of 3.0 V, temperature of 298 K, time of 12 h, the concentration of MnSO4 of 6%, concentration of pyrite of 4%, and concentration of acid of 10%), Cr is high to 93%. In the same time, the mechanism of electrolysis of pyrite was provided. The electrolysis of pyrite is actually the recycle of Mn ion between anodic surface and pyrite. At last, the production of FeSO4·7H2O through electrolysis of pyrite was introduced.

  17. Method of processing chloride waste

    International Nuclear Information System (INIS)

    In a method of applying molten salt electrolysis to chloride wastes discharged from a electrolytic refining step of a dry reprocessing step for spent fuels, and removed with transuranium elements of long half-decaying time, metals capable of alloying with alkali and alkaline earth metals under melting by electrolysis are used as a cathode material, and an electrolytic temperature is made higher than the melting point of salts in a molten salt electrolysis bath, to recover Li, Ca and Na as alloys with the cathode material in a first electrolysis step. Then, the electrolytic temperature is made higher than the melting point of the chloride salts remained in the bath after the electrolysis step described above by using the cathode material, to recover Ba, Rb, Sr and Cs of nuclear fission products also as alloys with the cathode material in a second electrolysis step. Accordingly, the amount of wastes formed can be reduced, and the wastes contain no heat generating nuclear fission elements. (T.M.)

  18. Performance characterization of rigid polyurethane foam with refined alkali lignin and modified alkali lignin

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-ming; YU Fei; FANG Gui-zhen; YANG Hui-jun

    2009-01-01

    The two kinds of rigid polyurethane (PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.

  19. 3D CFD Electrochemical And Heat Transfer Model Of An Internally Manifolded Solid Oxide Electrolysis Cell

    International Nuclear Information System (INIS)

    A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal

  20. Leaching Mechanism of Complicated Antimony-Lead Concentrate and Sulfur Formation in Slurry Electrolysis

    Institute of Scientific and Technical Information of China (English)

    WangChengyan; QiuDingfan; JiangPeihai

    2004-01-01

    Anodic reaction mechanism of complicated antimony-lead concentrate in slurry electrolysis was investigated by the anodic polarization curves determined under various conditions. The main reactions on the anode are the oxidations of FeCln(2-n) . Though the oxidation of jamesonite particle on the anode can occur during the whole process, it is less. With the help of mineralogy studies and relevant tests, the leaching reaction mechanism of jameson[to and gudmundite during slurry electrolysis was ascertained. Because of the oxidation reaction of FeCl3 produced by antimony-lead concentrate itself, the non-oxidation complex acid dissolution of jameson[re, the oxidation complex acid dissolution of gudmundite, and the oxidation of air carried by stirring, the leaching ratio of antimony reaches about 35% when HCl-NH4Cl solution is used to leach antimony-lead concentrate directly. So when the theoretical electric quantity is given to oxidation of antimony in slurry electrolysis, all of antimony, lead and iron containing in antimony-lead concentrate, are leached. The formation of sulfur is through the directly redox reaction of Fe3+ and jameson[re. The S2- in jamesonite is oxidized into S0 , and forms the crystals of sulfur again on the spot. The redox reaction of Fe3+ and H2S formed by non-oxidative acid dissolution of jamesonite is less.

  1. Water electrolysis with a conducting carbon cloth: subthreshold hydrogen generation and superthreshold carbon quantum dot formation.

    Science.gov (United States)

    Biswal, Mandakini; Deshpande, Aparna; Kelkar, Sarika; Ogale, Satishchandra

    2014-03-01

    A conducting carbon cloth, which has an interesting turbostratic microstructure and functional groups that are distinctly different from other ordered forms of carbon, such as graphite, graphene, and carbon nanotubes, was synthesized by a simple one-step pyrolysis of cellulose fabric. This turbostratic disorder and surface chemical functionalities had interesting consequences for water splitting and hydrogen generation when such a cloth was used as an electrode in the alkaline electrolysis process. Importantly, this work also gives a new twist to carbon-assisted electrolysis. During electrolysis, the active sites in the carbon cloth allow slow oxidation of its surface to transform the surface groups from COH to COOH and so forth at a voltage as low as 0.2 V in a two-electrode system, along with platinum as the cathode, instead of 1.23 V (plus overpotential), which is required for platinum, steel, or even graphite anodes. The quantity of subthreshold hydrogen evolved was 24 mL cm(-2)  h(-1) at 1 V. Interestingly, at a superthreshold potential (>1.23 V+overpotential), another remarkable phenomenon was found. At such voltages, along with the high rate and quantity of hydrogen evolution, rapid exfoliation of the tiny nanoscale (5-7 nm) units of carbon quantum dots (CQDs) are found in copious amounts due to an enhanced oxidation rate. These CQDs show bright-blue fluorescence under UV light. PMID:24492961

  2. Effect of Substrate Concentration to Anode Chamber Performance in Microbial Electrolysis Cell

    Directory of Open Access Journals (Sweden)

    Libertus Darus

    2015-11-01

    Full Text Available Microbial electrolysis is a promising process for bio-hydrogen production which might be implemented in waste water treatment in a near future. Unfortunately substrate could be converted into methane by acetoclastic methanogens and will reduce the coulombic efficiency (CE. The research objective was to study the competition between electrogens and methanogens for substrate in a continuous Microbial Electrolysis Cell (MEC.The competition was studied in relation to controlling acetate influent concentration (Cin from 35 to 1 mM with a fixed anode potential -350 mV, by assessing activity of electrogens as current density (CD, activity of acetoclastic methanogens as methanogenic consumed acetate (Cmeth, and CE and by measuring anolyte protein content to confirm a steady state condition. Controlling Cin from 35 to 1 mM resulted in tendency of both CD and Cmeth to decrease and CE to increase. At decreasing Cin from 35 to 5 mM which left excess acetate concentration in anolyte, the CEs were between 36.4% and 75.3%. At further decreasing Cin to 1 mM the acetate concentration was limited (Cef 0 mM, but the CE only reached 95.8%. Methanogenesis always occur and electrogens were not able to outcompete the acetoclastic methanogens even though the substrate concentration was limited.Keywords : microbial electrolysis cell, bio-hydrogen, metanogenesis, substrate concentration

  3. High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; G.K. Housley; K. DeWall; L. Moore-McAteer

    2012-09-01

    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this

  4. The Concept and Analytical Investigation of CO2 and Steam Co-Electrolysis for Resource Utilization in Space Exploration

    Science.gov (United States)

    McKellar, Michael G.; Stoots, Carl M.; Sohal, Manohar S.; Mulloth, Lila M.; Luna, Bernadette; Abney, Morgan B.

    2010-01-01

    CO2 acquisition and utilization technologies will have a vital role in designing sustainable and affordable life support and in situ fuel production architectures for human and robotic exploration of Moon and Mars. For long-term human exploration to be practical, reliable technologies have to be implemented to capture the metabolic CO2 from the cabin air and chemically reduce it to recover oxygen. Technologies that enable the in situ capture and conversion of atmospheric CO2 to fuel are essential for a viable human mission to Mars. This paper describes the concept and mathematical analysis of a closed-loop life support system based on combined electrolysis of CO2 and steam (co-electrolysis). Products of the coelectrolysis process include oxygen and syngas (CO and H2) that are suitable for life support and synthetic fuel production, respectively. The model was developed based on the performance of a co-electrolysis system developed at Idaho National Laboratory (INL). Individual and combined process models of the co-electrolysis and Sabatier, Bosch, Boudouard, and hydrogenation reactions are discussed and their performance analyses in terms of oxygen production and CO2 utilization are presented.

  5. The Alkali/Surfactant/ Polymer Process: Effects of Slug Size, Core Length and a Chase Polymer Le procédé alkali/surfactant/polymère : effets de la taille du bouchon, de la longueur de la carotte et d'un polymère de déplacement

    Directory of Open Access Journals (Sweden)

    Green K. A.

    2006-11-01

    Full Text Available An experimental study was conducted to examine the effects of slug size, core length, and a chase polymer on the effectiveness of the alkali/surfactant/polymer (A/S/P process in recovering waterflood residual oil. Core flood experiments were conducted with unfired linear Berea sandstone cores. The tertiary oil recovery, oil cut, pressure drop, and chemical propagation were measured for each flood. Tertiary oil recovery significantly increased with the slug size up to 0. 5 of a pore volume. Increasing the slug size further resulted in a smaller incremental increase in oil recovery. A slight increase in tertiary oil recovery was obtained when small size A/S/P slugs were followed with achase polymer having a viscosity higher than the slug. The lack of oil recovery with small A/S/P slugs was due to the consumption and dilution of the injected chemicals, especially the synthetic surfactant, due to adsorption and dispersion. Increasing the core length by a factor of 4. 5 (from 9 to 40. 6 cm had no significant effect on tertiary oil recovery. Chemical propagation was found to be a function of core length (i. e. , core Peclet number and the size of the chase polymer slug. Increasing core length and employing a chase polymer maintained the integrity of the A/S/P slug by decreasing the effect of dispersion and minimizing the influence of viscous fingering at the tail of the A/S/P slug. Une étude expérimentale a été effectuée pour examiner les effets de la taille du bouchon, de la longueur de la carotte et de l'emploi d'un polymère de déplacement sur l'efficacité du procédé A/S/P (alkali/surfactant/polymère dans la récupération d'huile résiduelle par injection d'eau. Les expériences d'injection ont été faites avec des carottes rectilignes en grès de Berea vert. La récupération tertiaire du pétrole, la présence d'eau, la perte de charge et la propagation chimique ont été mesurées pour chaque injection. La récupération tertiaire du

  6. Combined Electrolysis and Catalytic Exchange (CECE) upgraders - an alternative to Water Distillation (DW) heavy water upgraders

    International Nuclear Information System (INIS)

    All operating CANDU stations are equipped with Water Distillation (DW) systems for heavy water upgrading. An alternative process, Combined Electrolysis and Catalytic Exchange (CECE), is being considered for use in future CANDU stations. The CECE process has several operating advantages over DW systems, including lower emissions and heavy water losses. Changes in nuclear standards may change seismic requirements and classification of upgrader systems. These changes will likely increase the cost of heavy water upgraders, but the cost increase will be smaller for a CECE upgrader. Research at Chalk River Labs has identified materials for use in the CECE process that will not chemically or mechanically degrade when exposed to highly tritiated water. (author)

  7. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  8. Modeling Degradation in Solid Oxide Electrolysis Cells

    Energy Technology Data Exchange (ETDEWEB)

    Manohar S. Sohal; Anil V. Virkar; Sergey N. Rashkeev; Michael V. Glazoff

    2010-09-01

    Idaho National Laboratory has an ongoing project to generate hydrogen from steam using solid oxide electrolysis cells (SOECs). To accomplish this, technical and degradation issues associated with the SOECs will need to be addressed. This report covers various approaches being pursued to model degradation issues in SOECs. An electrochemical model for degradation of SOECs is presented. The model is based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic no equilibrium. It is shown that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, , within the electrolyte. The within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just near the oxygen electrode/electrolyte interface, leading to oxygen electrode delamination. These predictions are in accordance with the reported literature on the subject. Development of high pressures may be avoided by introducing some electronic conduction in the electrolyte. By combining equilibrium thermodynamics, no equilibrium (diffusion) modeling, and first-principles, atomic scale calculations were performed to understand the degradation mechanisms and provide practical recommendations on how to inhibit and/or completely mitigate them.

  9. Alkali and Halogen Chemistry in Volcanic Gases on Io

    CERN Document Server

    Schaefer, L

    2004-01-01

    We use chemical equilibrium calculations to model the speciation of alkalis and halogens in volcanic gases emitted on Io. The calculations cover wide temperature (500-2000 K) and pressure (10^-6 to 10^+1 bars) ranges, which overlap the nominal conditions at Pele (T = 1760 K, P = 0.01 bars). About 230 compounds of 11 elements (O, S, Li, Na, K, Rb, Cs, F, Cl, Br, I) are considered. We predict the major alkali and halogen species in a Pele-like volcanic gas and the major alklai and halogen condensates. We also model disequilibrium chemistry of the alkalis and halogens in the volcanic plume. Based on this work and our prior modeling for Na, K, and Cl in a volcanic plume, we predict the major loss processes for the alkali halide gases are photolysis and/or condensation onto grains. On the basis of elemental abundances and photochemical lifetimes, we recommend searching for gaseous KCl, NaF, LiF, LiCl, RbF, RbCl, CsF, and CsCl around volcanic vents during eruptions. Based on abundance considerations and observation...

  10. Inner-shell excitation of alkali-metal atoms

    International Nuclear Information System (INIS)

    Inner-shell excitation of alkali-metal atoms, which leads to auto-ionization, is reviewed. The validity of quantum mechanical approximation is analyzed and the importance of exchange and correlation is demonstrated. Basic difficulties in making accurate calculations for inner-shell excitation process are discussed. Suggestions are made for further study of inner-shell process in atoms and ions. (author). 26 refs, 4 figs, 1 tab

  11. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    Science.gov (United States)

    de Mello Luvielmo, Márcia; Borges, Caroline Dellinghausen; de Oliveira Toyama, Daniela; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  12. Structure of xanthan gum and cell ultrastructure at different times of alkali stress.

    Science.gov (United States)

    Luvielmo, Márcia de Mello; Borges, Caroline Dellinghausen; Toyama, Daniela de Oliveira; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  13. Steam electrolysis by solid oxide electrolysis cells (SOECs) with proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2014-01-01

    Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions.

  14. Steam electrolysis by solid oxide electrolysis cells (SOECs) with proton-conducting oxides.

    Science.gov (United States)

    Bi, Lei; Boulfrad, Samir; Traversa, Enrico

    2014-12-21

    Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions. PMID:25134016

  15. THE DIGESTION OPERATION IN THE ALKALI ALUMINAT SOLUTIONS OF ALUMINUM HYDROXIDES IN THE BOEHMITIC BAUXITES

    OpenAIRE

    Sami ŞAHİN

    1999-01-01

    At present more than 90 per cent of the world's alumina is produced by the Bayer process, a simple technology providing high purity final product. A part from some exceptional local conditions, bauxite is processed almost solely by this technology. As a benefication process, alumina production releases the aluminum oxide content of bauxite from other accompanying oxides thus providing alumina suitable for electrolysis in a cryolite melt. The basic theory of the Bayer process was elaborated by...

  16. CO2 Fixation by Membrane Separated NaCl Electrolysis

    Directory of Open Access Journals (Sweden)

    Hyun Sic Park

    2015-08-01

    Full Text Available Atmospheric concentrations of carbon dioxide (CO2, a major cause of global warming, have been rising due to industrial development. Carbon capture and storage (CCS, which is regarded as the most effective way to reduce such atmospheric CO2 concentrations, has several environmental and technical disadvantages. Carbon capture and utilization (CCU, which has been introduced to cover such disadvantages, makes it possible to capture CO2, recycling byproducts as resources. However, CCU also requires large amounts of energy in order to induce reactions. Among existing CCU technologies, the process for converting CO2 into CaCO3 requires high temperature and high pressure as reaction conditions. This study proposes a method to fixate CaCO3 stably by using relatively less energy than existing methods. After forming NaOH absorbent solution through electrolysis of NaCl in seawater, CaCO3 was precipitated at room temperature and pressure. Following the experiment, the resulting product CaCO3 was analyzed with Fourier transform infrared spectroscopy (FT-IR; field emission scanning electron microscopy (FE-SEM image and X-ray diffraction (XRD patterns were also analyzed. The results showed that the CaCO3 crystal product was high-purity calcite. The study shows a successful method for fixating CO2 by reducing carbon dioxide released into the atmosphere while forming high-purity CaCO3.

  17. Investigation of Coliform Removal from Drinking Water by Electrolysis

    Directory of Open Access Journals (Sweden)

    A. Rahmani

    2008-07-01

    Full Text Available Introduction & Objective: The practice of eliminating pathogenic microorganisms in water dates back to ancient times. The most common methods for water disinfection are using chemicals, Ozonation, Ultra Violet ray, Membrane Processes and etc. There has been considerable interest in disinfection of water by using electrochemical methods in recent years. The main purpose of this study is to conduct experimental investigation of water disinfection by using the electrolysis method. Inactivation and killing Coliform in polluted waters was investigated by different voltage, electrodes (Al, St and Cu and distance between electrodes.Materials & Methods: The polluted water was prepared by adding a colony of coliform growth on EMB in raw water. Experiments were done similarly via the same electrolyzes time, electrodes distance and voltage intensity for all types of combinations of electrodes respectively. Results: The experimental results show that the removal efficiency depends on the voltage and electrodes material. From the experiments carried out at 10 V. and at current intensity of 135 mA, it was found that five-minute period was sufficient for disinfecting water using Stainless Steel electrodes.Conclusion: Due to the results, the electrochemical methods can be proposed as a promising cleaning and purifying method for water disinfection.

  18. Laser-synchrotron studies of the dynamics of UV-photon-stimulated desorption in alkali halides

    International Nuclear Information System (INIS)

    Laser-synchrotron studies of neutral alkali emission from alkali halide crystals are yielding new insights into the dynamics of energy absorption, energy localization and bond-breaking in photon-stimulated desorption. The ground-state neutral desorption is triggered by the thermal diffusion of photon-induced electronic defects; however, the excited-state neutral alkalis are formed in a surface-specific process on an extremely short time scale. In addition, there is new evidence for a surface overlayer which retards substrate desorption, thus suggesting a new approach to the optical damage problem at ultraviolet wavelengths. 8 references

  19. Laser-synchrotron studies of the dynamics of UV-photon-stimulated desorption in alkali halides

    International Nuclear Information System (INIS)

    Laser-synchrotron studies of neutral alkali emission from alkali halide crystals are yielding new insights into the dynamics of energy absorption, energy localization and bond-breaking in photon-stimulated desorption. The ground-state neutral desorption is triggered by thermal diffusion of photon-induced electronic defects; however, the excited-state neutral alkalis are formed in a surface-specific process on an extremely short time scale. In addition, there is new evidence for a surface overlayer which retards substrate desorption, thus suggesting a new approach to the optical damage problem at ultraviolet wavelengths

  20. Trace Element Geochemistry of Hannuoba Ultramafic Inclusion—bearing Alkali Basalts

    Institute of Scientific and Technical Information of China (English)

    支霞臣

    1990-01-01

    Presented in this paper are the trace element abundances of 16 samples of Hannuoba ultramafic inclusion-bearing aldali basalts,which were determined by instrumental neutron activation analysis and X-ray fluorescence spectrometry.The Petrogenesis of the alkali basalt suite has been modeled by batch partial melting and and Rayleigh fractional crystallization processes,The geochemical characteristics of the mantle source from where alkali basalts were derived are described in terms of variations in trace element abundances of the alkali basalt suite.

  1. Comparative thermoeconomic analysis of hydrogen production by water electrolysis and by ethanol steam reforming

    Energy Technology Data Exchange (ETDEWEB)

    Riveros-Godoy, Gustavo; Chavez-Rodriguez, Mauro; Cavaliero, Carla [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Mechanical Engineering School], Email: garg@fem.unicamp.br

    2010-07-01

    Hydrogen is the focus of this work that evaluates in comparative form through thermo economic analysis two hydrogen production processes: water electrolysis and ethanol steam reforming. Even though technical-economical barriers still exist for the development of an economy based on hydrogen, these difficulties are opportunities for the appearance of new business of goods and services, diversification of the energy mix, focus of research activities, development and support to provide sustainability to the new economy. Exergy and rational efficiency concept are used to make a comparison between both processes. (author)

  2. High Temperature Electrolysis using Electrode-Supported Cells

    International Nuclear Information System (INIS)

    An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. The cells currently under study were developed primarily for the fuel cell mode of operation. Results presented in this paper were obtained from single cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes (∼10 (micro)m thick), nickel-YSZ steam/hydrogen electrodes (∼1400 (micro)m thick), and manganite (LSM) air-side electrodes (∼90 (micro)m thick). The purpose of the present study was to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of DC potential sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-duration testing, first in the fuel cell mode, then in the electrolysis mode over more than 500 hours of operation. Results indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of the single-cell test apparatus developed specifically for these experiments.

  3. High Temperature Electrolysis using Electrode-Supported Cells

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots

    2010-07-01

    An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. The cells currently under study were developed primarily for the fuel cell mode of operation. Results presented in this paper were obtained from single cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes (~10 µm thick), nickel-YSZ steam/hydrogen electrodes (~1400 µm thick), and manganite (LSM) air-side electrodes (~90 µm thick). The purpose of the present study was to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of DC potential sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-duration testing, first in the fuel cell mode, then in the electrolysis mode over more than 500 hours of operation. Results indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of the single-cell test apparatus developed specifically for these experiments.

  4. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    Science.gov (United States)

    Zhu, Xiuping; Hatzell, Marta C; Logan, Bruce E

    2014-04-01

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration. PMID:24741666

  5. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    KAUST Repository

    Zhu, Xiuping

    2014-03-24

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.

  6. Coupling of microbial electrolysis cells and dark fermentation to enhance the production of hydrogen from agro-industrial wastewaters

    OpenAIRE

    Marone, Antonella; Ayala, Olga; Trably, Eric; Carmona Martinez, Alessandro; Moscoviz, Roman; Latrille, Eric; Alcaraz-Gonzalez, Victor; Bernet, Nicolas

    2015-01-01

    The aim of this work is the development of a feasible, cascade two-step BioH2 production process from Organic Wastewater (WW), combining dark fermentation (DF) and Microbial Electrolysis Cells (MECs). Such coupling of DF and ME constitutes a technological cornerstone within the concept of an environmental biorefinery. Five different WW coming from cheese (CW), fruit juice (FJW), paper (PW), sugar (SW) and fruit processing (FPW) factories were selected among 21 different WW collected from a wi...

  7. Solid oxide electrolysis cell for decomposition of tritiated water

    International Nuclear Information System (INIS)

    The decomposition of tritiated water vapor with solid oxide electrolysis cell was proposed for the application to the D-T fusion reactor system. This method is essentially free from problems such as large tritium inventory, radiation damage, and generation of solid waste, so it is expected to be a promising one. Electrolysis of water vapor in argon carrier was performed using tube-type stabilized zirconia cell with porous platinum electrodes in the temperature range of 5000C to 9500C. High conversion ratio from water to hydrogen up to 99.9% was achieved. The characteristics of the cell is deduced from the Nernst's equation and conversion ratio is described as the function of the open circuit voltage. Experimental results agreed with the equation. Isotope effect in electrolysis is also discussed and experiments with heavy water were carried out. Obtained separation factor was slightly higher than the theoretical value

  8. High temperature electrolysis of steam and carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hoejgaard Jensen, Soeren [H.C. Oersted Institute, Copenhagen (Denmark); Hoegh, Jens V.T.; Barfod, Rasmus; Mogensen, Mogens [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    2003-09-01

    The vision behind this work is establishment of methods for cheap production of hydrogen, H{sub 2}, and methane, CH{sub 4}, by electrolysis. CH{sub 4} is a particular suitable storage medium for renewable energy. Preliminary electrolysis experiments with a second generation of solid oxide fuel cells developed at Risoe National Laboratory, Denmark, show that these cells also have a high potential as solid oxide electrolyse cells. Furthermore, the experiments indicate that production of CH{sub 4} by high temperature electrolysis of mixtures of H{sub 2} and CO{sub 2} is possible using these cells, but very high gas pressure seems necessary to obtain acceptable yields. The results also indicate that much more research and development work is needed in order to make a sufficient durable electrolyse cell. (au)

  9. 脉冲电解电火花复合小孔加工工艺的探讨%A Discussion on the Pulse Electrolysis and EDM Compound Processing Technology for Small Holes

    Institute of Scientific and Technical Information of China (English)

    陈钢; 沈立勤

    2001-01-01

    The basic principle of electrolytic machining and the superiority of its processing technology were introduced. The ECM/EDM (electrochemical melting and electric discharge machining) compound machining process was stated. And the foreign developing status quo of the ECM/EDM compound processing of deep and small holes was mentioned.%介绍了电解加工的基本原理及其加工工艺优点,阐述了 ECM(电化学溶解及电火花熔蚀 )/EDM(电火花放电腐蚀成型 )复合加工过程,以及国外深小孔 ECM/EDM复合加工的发展现状。

  10. Alkali silica reaction in concrete induced by mortar adhered to recycled aggregate

    OpenAIRE

    Etxeberria, M.; Vázquez, E.

    2010-01-01

    The durability of recycled concrete must be determined before this material can be used in construction. In this paper the alkali-silica reaction in recycled concrete is analyzed. The recycled concrete is made with recycled aggregates, composed by original limestone aggregates and adhered mortar with reactive silica sand, and high alkali content cement. Due to the manufacturing process used for concrete production and the high water absorption capacity of recycled aggregates, cement accumulat...

  11. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and an immobilized electrolyte allow for reversible operation as electrolysis cell or fuel...... cell. In the present work we demonstrate the application of hydrophobic, porous, and electro-catalytically active gas diffusion electrodes. PTFE particles and silver nanowires as electro-catalysts were used in the gas diffusion electrodes. Impedance spectroscopy and cyclic voltammetry were performed to...

  12. Foam Based Gas Diffusion Electrodes for Reversible Alkaline Electrolysis Cells

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2014-01-01

    Alkaline electrolysis cells operated at 250 °C and 40 bar have shown to be able to convert electrical energy into chemical energy in the form of hydrogen at very high efficiencies and power densities. Foam based gas diffusion electrodes and a liquid immobilized electrolyte allow the operation of...... the newly designed electrolysis cell as a fuel cell, but condensation of steam may lead to blocked pores, thereby inhibiting gas diffusion and decreasing the performance of the cell. In the here presented work we present the application of a hydrophobic, porous, and electro-catalytically active layer...

  13. Carbon dioxide and water vapor high temperature electrolysis

    Science.gov (United States)

    Isenberg, Arnold O.; Verostko, Charles E.

    1989-01-01

    The design, fabrication, breadboard testing, and the data base obtained for solid oxide electrolysis systems that have applications for planetary manned missions and habitats are reviewed. The breadboard tested contains sixteen tubular cells in a closely packed bundle for the electrolysis of carbon dioxide and water vapor. The discussion covers energy requirements, volume, weight, and operational characteristics related to the measurement of the reactant and product gas compositions, temperature distribution along the electrolyzer tubular cells and through the bundle, and thermal energy losses. The reliability of individual cell performance in the bundle configuration is assessed.

  14. Power to fuel using electrolysis and CO2 capture

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Graves, Christopher R.; Chatzichristodoulou, Christodoulos;

    2014-01-01

    ” hydrocarbon fuels seem particularlybenign to replace the fossil fuels, and electrolysis seems to be a feasible step in production of green fuels. In particular, synthetic hydrocarbon based fuel will be necessary for the heavy transportation vehicles such as airplanes, ships, and trucks. More than 65 % of the......Conversion of renewable electricity to synthetic fuel using electrolysis to produce at H2 and CO, which is furtherused to form liquid or gaseous fuel, called “power to fuel” or “power2fuel” has got a lot of attention recently.This is because synthetic fuels (synfuels) in the form CO2 neutral “green...... large scale fuel production....

  15. From Oxygen Generation to Metals Production: In Situ Resource Utilization by Molten Oxide Electrolysis

    Science.gov (United States)

    Khetpal, Deepak; Ducret, Andrew C.; Sadoway, Donald R.

    2003-01-01

    For the exploration of other bodies in the solar system, electrochemical processing is arguably the most versatile technology for conversion of local resources into usable commodities: by electrolysis one can, in principle, produce (1) breathable oxygen, (2) silicon for the fabrication of solar cells, (3) various reactive metals for use as electrodes in advanced storage batteries, and (4) structural metals such as steel and aluminum. Even so, to date there has been no sustained effort to develop such processes, in part due to the inadequacy of the database. The objective here is to identify chemistries capable of sustaining molten oxide electrolysis in the cited applications and to examine the behavior of laboratory-scale cells designed to generate oxygen and to produce metal. The basic research includes the study of the underlying high-temperature physical chemistry of oxide melts representative of lunar regolith and of Martian soil. To move beyond empirical approaches to process development, the thermodynamic and transport properties of oxide melts are being studied to help set the limits of composition and temperature for the processing trials conducted in laboratory-scale electrolysis cells. The goal of this investigation is to deliver a working prototype cell that can use lunar regolith and Martian soil to produce breathable oxygen along with metal by-product. Additionally, the process can be generalized to permit adaptation to accommodate different feedstock chemistries, such as those that will be encountered on other bodies in the solar system. The expected results of this research include: (1) the identification of appropriate electrolyte chemistries; (2) the selection of candidate anode and cathode materials compatible with electrolytes named above; and (3) performance data from a laboratory-scale cell producing oxygen and metal. On the strength of these results it should be possible to assess the technical viability of molten oxide electrolysis for in

  16. Real-time quantum feedback control with cold alkali atoms

    OpenAIRE

    Geremia, J. M.

    2007-01-01

    This chapter describes recent experiments involving continuous measurement and quantum feedback control of collective spin in a cloud of cold alkali atoms. While measurement by itself can generate entanglement between different atoms in the sample by virtue of conditional spin-squeezing, the squeezed state produced in any individual instance of the measurement is randomly distributed. Incorporating real-time feedback control into the observation process suppresses the statistical dispersion o...

  17. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    Science.gov (United States)

    Allagui, Anis; Rojas, Andrea Espinel; Bonny, Talal; Elwakil, Ahmed S.; Abdelkareem, Mohammad Ali

    2016-05-01

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as "random," and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  18. Microbial electrolysis contribution to anaerobic digestion of waste activated sludge, leading to accelerated methane production

    DEFF Research Database (Denmark)

    Liu, Wenzong; Cai, Weiwei; Guo, Zechong;

    2016-01-01

    Methane production rate (MPR) in waste activated sludge (WAS) digestion processes is typically limitedby the initial steps of complex organic matter degradation, leading to a limited MPR due to sludgefermentation speed of solid particles. In this study, a novel microbial electrolysis AD reactor (ME....../m3 reactor/d in AD). The methane production yield reached 116.2 mg/g VSS in the ME-ADreactor. According to balance calculation on electron transfer and methane yield, the increasedmethane production was mostly dependent on electron contribution through the ME system. Thus, theuse of the novel ME...

  19. Pilot study of mechanism of property-modified anode in aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    肖劲; 杨建红; 胡国荣; 赖延清; 王先黔; 刘业翔

    2003-01-01

    On the basis of serial laboratory research and industrial test, the mechanism of saving energy and reducing carbon consumption of property-modified prebaked anode in aluminum electrolysis was discussed. It is considered that the anodic over voltage is affected by the concentration of carbon monoxide surrounding anode. The property-modified prebaked anode can restrain the production of carbon monoxide. The reason of reducing carbon consumption was also analyzed, the result shows that besides physical action, chemical action also exists in the process where additives change the reaction rate of anodes.

  20. Advancements in flowing diode pumped alkali lasers

    Science.gov (United States)

    Pitz, Greg A.; Stalnaker, Donald M.; Guild, Eric M.; Oliker, Benjamin Q.; Moran, Paul J.; Townsend, Steven W.; Hostutler, David A.

    2016-03-01

    Multiple variants of the Diode Pumped Alkali Laser (DPAL) have recently been demonstrated at the Air Force Research Laboratory (AFRL). Highlights of this ongoing research effort include: a) a 571W rubidium (Rb) based Master Oscillator Power Amplifier (MOPA) with a gain (2α) of 0.48 cm-1, b) a rubidium-cesium (Cs) Multi-Alkali Multi-Line (MAML) laser that simultaneously lases at both 795 nm and 895 nm, and c) a 1.5 kW resonantly pumped potassium (K) DPAL with a slope efficiency of 50%. The common factor among these experiments is the use of a flowing alkali test bed.

  1. High effective silica fume alkali activator

    Indian Academy of Sciences (India)

    Vladimír Živica

    2004-04-01

    Growing demands on the engineering properties of cement based materials and the urgency to decrease unsuitable ecologic impact of Portland cement manufacturing represent significant motivation for the development of new cement corresponding to these aspects. One category represents prospective alkali activated cements. A significant factor influencing their properties is alkali activator used. In this paper we present a new high effective alkali activator prepared from silica fume and its effectiveness. According to the results obtained this activator seems to be more effective than currently used activators like natrium hydroxide, natrium carbonate, and water glass.

  2. Recycling Carbon Dioxide into Sustainable Hydrocarbon Fuels: Electrolysis of Carbon Dioxide and Water

    Science.gov (United States)

    Graves, Christopher Ronald

    Great quantities of hydrocarbon fuels will be needed for the foreseeable future, even if electricity based energy carriers begin to partially replace liquid hydrocarbons in the transportation sector. Fossil fuels and biomass are the most common feedstocks for production of hydrocarbon fuels. However, using renewable or nuclear energy, carbon dioxide and water can be recycled into sustainable hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse of fuel combustion). Capture of CO2 from the atmosphere would enable a closed-loop carbon-neutral fuel cycle. The purpose of this work was to develop critical components of a system that recycles CO2 into liquid hydrocarbon fuels. The concept is examined at several scales, beginning with a broad scope analysis of large-scale sustainable energy systems and ultimately studying electrolysis of CO 2 and H2O in high temperature solid oxide cells as the heart of the energy conversion, in the form of three experimental studies. The contributions of these studies include discoveries about electrochemistry and materials that could significantly improve the overall energy use and economics of the CO2-to-fuels system. The broad scale study begins by assessing the sustainability and practicality of the various energy carriers that could replace petroleum-derived hydrocarbon fuels, including other hydrocarbons, hydrogen, and storage of electricity on-board vehicles in batteries, ultracapacitors, and flywheels. Any energy carrier can store the energy of any energy source. This sets the context for CO2 recycling -- sustainable energy sources like solar and wind power can be used to provide the most energy-dense, convenient fuels which can be readily used in the existing infrastructure. The many ways to recycle CO2 into hydrocarbons, based on thermolysis, thermochemical loops, electrolysis, and photoelectrolysis of CO2 and/or H 2O, are critically reviewed. A process based on high temperature co-electrolysis

  3. Preparation of Mg-Li alloys by electrolysis in molten salt at low temperature

    Institute of Scientific and Technical Information of China (English)

    Mi Lin Zhang; Yong De Yan; Zhi Yao Hou; Lu An Fan; Zeng Chen; Ding Xiang Tang

    2007-01-01

    A new technology for preparation of low cost Mg-Li alloys was studied. The alloys were prepared by electrolysis in molten were investigated, and optimal electrolysis parameters were obtained. Mg-Li alloys with low lithium content (about 25%) were prepared by the unique method of a higher post-thermal treatment temperature after electrolysis at low temperature. The results showed that the electrolysis can be carried out at low temperature, which resulted in reducing preparation cost due to energy saving.The new technology for the preparation of Mg-Li alloy by electrolysis in molten salt was proved to be feasible.

  4. CHALLENGES IN GENERATING HYDROGEN BY HIGH TEMPERATURE ELECTROLYSIS USING SOLID OXIDE CELLS

    Energy Technology Data Exchange (ETDEWEB)

    M. S. Sohal; J. E. O' Brien; C. M. Stoots; M. G. McKellar; J. S. Herring; E. A. Harvego

    2008-03-01

    Idaho National Laboratory’s (INL) high temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells is presented in this paper. The research results reported here have been obtained in a laboratory-scale apparatus. These results and common scale-up issues also indicate that for the technology to be successful in a large industrial setting, several technical, economical, and manufacturing issues have to be resolved. Some of the issues related to solid oxide cells are stack design and performance optimization, identification and evaluation of cell performance degradation parameters and processes, integrity and reliability of the solid oxide electrolysis (SOEC) stacks, life-time prediction and extension of the SOEC stack, and cost reduction and economic manufacturing of the SOEC stacks. Besides the solid oxide cells, balance of the hydrogen generating plant also needs significant development. These issues are process and ohmic heat source needed for maintaining the reaction temperature (~830°C), high temperature heat exchangers and recuperators, equal distribution of the reactants into each cell, system analysis of hydrogen and associated energy generating plant, and cost optimization. An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a cost of $3.23/kg of hydrogen assuming an internal rate of return of 10%. These issues need interdisciplinary research effort of federal laboratories, solid oxide cell manufacturers, hydrogen consumers, and other such stakeholders. This paper discusses research and development accomplished by INL on such issues and highlights associated challenges that need to

  5. HIGH-TEMPERATURE CO-ELECTROLYSIS OF H2O AND CO2 FOR SYNGAS PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Stoots, C.M.

    2006-11-01

    Worldwide, the demand for light hydrocarbon fuels like gasoline and diesel oil is increasing. To satisfy this demand, oil companies have begun to utilize oil deposits of lower hydrogen content (an example is the Athabasca Oil Sands). Additionally, the higher contents of sulfur and nitrogen of these resources requires processes such as hydrotreating to meet environmental requirements. In the mean time, with the price of oil currently over $50 / barrel, synthetically-derived hydrocarbon fuels (synfuels) have become economical. Synfuels are typically produced from syngas – hydrogen (H2) and carbon monoxide (CO) -- using the Fischer-Tropsch process, discovered by Germany before World War II. South Africa has used synfuels to power a significant number of their buses, trucks, and taxicabs. The Idaho National Laboratory (INL), in conjunction with Ceramatec Inc. (Salt Lake City, USA) has been researching for several years the use of solid-oxide fuel cell technology to electrolyze steam for large-scale nuclear-powered hydrogen production. Now, an experimental research project is underway at the INL to investigate the feasibility of producing syngas by simultaneously electrolyzing at high-temperature steam and carbon dioxide (CO2) using solid oxide fuel cell technology. The syngas can then be used for synthetic fuel production. This program is a combination of experimental and computational activities. Since the solid oxide electrolyte material is a conductor of oxygen ions, CO can be produced by electrolyzing CO2 sequestered from some greenhouse gas-emitting process. Under certain conditions, however, CO can further electrolyze to produce carbon, which can then deposit on cell surfaces and reduce cell performance. The understanding of the co-electrolysis of steam and CO2 is also complicated by the competing water-gas shift reaction. Results of experiments and calculations to date of CO2 and CO2/H2O electrolysis will be presented and discussed. These will include

  6. PREPARATION OF HOLLOW LATEX PARTICLES BY ALKALI-ACID TREATMENT

    Institute of Scientific and Technical Information of China (English)

    郝冬梅; 王新灵; 朱卫华; 唐小真; 刘成岑; 施凯

    2001-01-01

    Hollow polymer latex particles were prepared by seeded emulsion polymerization. A seed latex consisting of styrene (St), butyl acrylate(BA) copolymer was first prepared, and seeded terpolymerization of St-BA-MA(methacrylic acid) were then carried out in the absence of surfactant. Final latex was treated by a two-step treatment under alkaline and acidic conditions, thus, the particles with hollow structure were obtained. We discussed the effects of pH value, temperature and time in alkali and acid treatment processes on hollow structure within the polymer latex particles and amount of carboxylic group on particle surface. The results show that the hollow polymer latex particles with the largest hollow size can be obtained under a certain condition (pH12.5, 90°C, 3 h in alkali treatment stage and pH2.5, 85°C, 3 h in acid treatment stage).

  7. Density of mixed alkali borate glasses: A structural analysis

    International Nuclear Information System (INIS)

    Density of mixed alkali borate glasses has been correlated with the glass structure. It is assumed that in such glasses each alkali oxide associates with a proportional quantity of B2O3. The number of BO3 and BO4 units related to each type of alkali oxide depends on the total concentration of alkali oxide. It is concluded that in mixed alkali borate glasses the volumes of structural units related to an alkali ion are the same as in the corresponding binary alkali borate glass. This reveals that each type of alkali oxide forms its own borate matrix and behaves as if not affected with the presence of the other alkali oxide. Similar conclusions are valid for borate glasses with three types of alkali oxide

  8. Density of mixed alkali borate glasses: A structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Doweidar, H. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt)]. E-mail: hdoweidar@mans.edu.eg; El-Damrawi, G.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt); Moustafa, Y.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt); Ramadan, R.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt)

    2005-05-15

    Density of mixed alkali borate glasses has been correlated with the glass structure. It is assumed that in such glasses each alkali oxide associates with a proportional quantity of B{sub 2}O{sub 3}. The number of BO{sub 3} and BO{sub 4} units related to each type of alkali oxide depends on the total concentration of alkali oxide. It is concluded that in mixed alkali borate glasses the volumes of structural units related to an alkali ion are the same as in the corresponding binary alkali borate glass. This reveals that each type of alkali oxide forms its own borate matrix and behaves as if not affected with the presence of the other alkali oxide. Similar conclusions are valid for borate glasses with three types of alkali oxide.

  9. Production of Hydrogen and Synthesis Gas by High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Høgh, Jens Valdemar Thorvald; Mogensen, Mogens Bjerg

    2009-01-01

    electrolysis cells was found to be influenced by the adsorption of impurities from the gasses, whereas the application of chromium containing interconnect plates and glass sealings do not seem to influence the durability. Cleaning the inlet gasses to the Ni/YSZ electrode resulted in operation without any long...

  10. Analysis of cavitation effect for water purifier using electrolysis

    Science.gov (United States)

    Shin, Dong Ho; Ko, Han Seo; Lee, Seung Ho

    2015-11-01

    Water is a limited and vital resource, so it should not be wasted by pollution. A development of new water purification technology is urgent nowadays since the original and biological treatments are not sufficient. The microbubble-aided method was investigated for removal of algal in this study since it overcomes demerits of the existing purification technologies. Thus, the cavitation effect in a venturi-type tube using the electrolysis was analyzed. Ruthenium-coated titanium plates were used as electrodes. Optimum electrode interval and applied power were determined for the electrolysis. Then, the optimized electrodes were installed in the venturi-type tube for generating cavitation. The cavitation effect could be enhanced without any byproduct by the bubbly flow induced by the electrolysis. The optimum mass flow rate and current were determined for the cavitation with the electrolysis. Finally, the visualization techniques were used to count the cell number of algal and microbubbles for the confirmation of the performance. As a result, the energy saving and high efficient water purifier was fabricated in this study. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. 2013R1A2A2A01068653).

  11. PEM Electrolysis H2A Production Case Study Documentation

    Energy Technology Data Exchange (ETDEWEB)

    James, Brian [Strategic Analysis Inc. (SA), Arlington, Virginia; Colella, Whitney [Strategic Analysis Inc. (SA), Arlington, Virginia; Moton, Jennie [Strategic Analysis Inc. (SA), Arlington, Virginia; Saur, G. [Strategic Analysis Inc. (SA), Arlington, Virginia; Ramsden, T. [Strategic Analysis Inc. (SA), Arlington, Virginia

    2013-12-31

    This report documents the development of four DOE Hydrogen Analysis (H2A) case studies for polymer electrolyte membrane (PEM) electrolysis. The four cases characterize PEM electrolyzer technology for two hydrogen production plant sizes (Forecourt and Central) and for two technology development time horizons (Current and Future).

  12. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation.

    Science.gov (United States)

    Stehling, Michael K; Guenther, Enric; Mikus, Paul; Klein, Nina; Rubinsky, Liel; Rubinsky, Boris

    2016-01-01

    Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs "Synergistic electrolysis and electroporation" (SEE). The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to establish SEE treatment parameters of clinical utility. We examined two SEE methods. One of the methods employs multiple electrochemotherapy-type reversible electroporation magnitude pulses, designed in such a way that the charge delivered during the electroporation pulses generates the electrolytic products. The second SEE method combines the delivery of a small number of electrochemotherapy magnitude electroporation pulses with a low voltage electrolysis generating DC current in three different ways. We show that both methods can produce lesion with dimensions of clinical utility, without the need to inject drugs as in electrochemotherapy, faster than with conventional electrolysis and with lower electric fields than irreversible electroporation and nanosecond pulsed ablation. PMID:26866693

  13. Synergistic Combination of Electrolysis and Electroporation for Tissue Ablation.

    Directory of Open Access Journals (Sweden)

    Michael K Stehling

    Full Text Available Electrolysis, electrochemotherapy with reversible electroporation, nanosecond pulsed electric fields and irreversible electroporation are valuable non-thermal electricity based tissue ablation technologies. This paper reports results from the first large animal study of a new non-thermal tissue ablation technology that employs "Synergistic electrolysis and electroporation" (SEE. The goal of this pre-clinical study is to expand on earlier studies with small animals and use the pig liver to establish SEE treatment parameters of clinical utility. We examined two SEE methods. One of the methods employs multiple electrochemotherapy-type reversible electroporation magnitude pulses, designed in such a way that the charge delivered during the electroporation pulses generates the electrolytic products. The second SEE method combines the delivery of a small number of electrochemotherapy magnitude electroporation pulses with a low voltage electrolysis generating DC current in three different ways. We show that both methods can produce lesion with dimensions of clinical utility, without the need to inject drugs as in electrochemotherapy, faster than with conventional electrolysis and with lower electric fields than irreversible electroporation and nanosecond pulsed ablation.

  14. Alkali-metal intercalation in carbon nanotubes

    Science.gov (United States)

    Béguin, F.; Duclaux, L.; Méténier, K.; Frackowiak, E.; Salvetat, J. P.; Conard, J.; Bonnamy, S.; Lauginie, P.

    1999-09-01

    We report on successful intercalation of multiwall (MWNT) and single wall (SWNT) carbon nanotubes with alkali metals by electrochemical and vapor phase reactions. A LiC10 compound was produced by full electrochemical reduction of MWNT. KC8 and CsC8-MWNT first stage derivatives were synthesized in conditions of alkali vapor saturation. Their identity periods and the 2×2 R 0° alkali superlattice are comparable to their parent graphite compounds. The dysonian shape of KC8 EPR line and the temperature-independent Pauli susceptibility are both characteristic of a metallic behavior, which was confirmed by 13C NMR anisotropic shifts. Exposure of SWNT bundles to alkali vapor led to an increase of the pristine triangular lattice from 1.67 nm to 1.85 nm and 1.87 nm for potassium and rubidium, respectively.

  15. Characterization of Waste Poly(Ethylene-Terephthalate after Alkali Treatment

    Directory of Open Access Journals (Sweden)

    Rešček, A.

    2011-07-01

    in contact angle (which is measured with water indicates an increase in surface hydrophilicity and increase in the number of present polar -OH and -COOH groups formed during the partial degradation. Also, the values of total surface energies and their polar and dispersive components indicate that during the alkali treatment the surface characteristics of PET flakes were slightly changed due to depolymerization (Table 3. Generally, it can be concluded that partial depolymerization of PET flakes occurs during the alkali treatment but the material retains its good properties and it is appropriate for the further recycling process.

  16. Durability of solid oxide electrolysis cells for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Hauch, A.; Hoejgaard Jensen, S.; Dalgaard Ebbesen, S.

    2007-05-15

    In the perspective of the increasing interest in renewable energy and hydrogen economy, the reversible solid oxide cells (SOCs) is a promising technology as it has the potential of providing efficient and cost effective hydrogen production by high temperature electrolysis of steam (HTES). Furthermore development of such electrolysis cells can gain from the results obtained within the R and D of SOFCs. For solid oxide electrolysis cells (SOEC) to become interesting from a technological point of view, cells that are reproducible, high performing and long-term stable need to be developed. In this paper we address some of the perspectives of the SOEC technology i.e. issues such as a potential H2 production price as low as 0.71 US dollar/kg H{sub 2} using SOECs for HTES; is there a possible market for the electrolysers? and what R and D steps are needed for the realisation of the SOEC technology? In the experimental part we present electrolysis test results on SOCs that have been optimized for fuel cell operation but applied for HTES. The SOCs are produced on a pre-pilot scale at Risoe National Laboratory. These cells have been shown to have excellent initial electrolysis performance, but the durability of such electrolysis cells are not optimal and examples of results from SOEC tests over several hundreds of hours are given here. The long-term tests have been run at current densities of -0.5 A/cm{sup 2} and -1 A/cm{sup 2}, temperatures of 850 deg. C and 950 deg. C and p(H{sub 2}O)/p(H{sub 2}) of 0.5/0.5 and 0.9/0.1. Long-term degradation rates are shown to be up to 5 times higher for SOECs compared to similar SOFC testing. Furthermore, hydrogen and synthetic fuel production prices are calculated using the experimental results from long-term electrolysis test as input and a short outlook for the future work on SOECs will be given as well. (au)

  17. Pre-investigation of water electrolysis for flexible energy storage at large scales: the case of the Spanish power system

    OpenAIRE

    Gutierrez Martin, Fernando; Ochoa Mendoza, Almudena; Rodriguez Anton, Luis Miguel

    2015-01-01

    This report analyzes the basis of hydrogen and power integration strategies, by using water electrolysis processes as a means of flexible energy storage at large scales. It is a prospective study, where the scope is to describe the characteristics of current power systems (like the generation technologies, load curves and grid constraints), and define future scenarios of hydrogen for balancing the electrical grids, considering the efficiency, economy and easiness of operations. We focus in th...

  18. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    Science.gov (United States)

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  19. Water Content of Lunar Alkali Fedlspar

    Science.gov (United States)

    Mills, R. D.; Simon, J. I.; Wang, J.; Alexander, C. M. O'D.; Hauri, E. H.

    2016-01-01

    Detection of indigenous hydrogen in a diversity of lunar materials, including volcanic glass, melt inclusions, apatite, and plagioclase suggests water may have played a role in the chemical differentiation of the Moon. Spectroscopic data from the Moon indicate a positive correlation between water and Th. Modeling of lunar magma ocean crystallization predicts a similar chemical differentiation with the highest levels of water in the K- and Th-rich melt residuum of the magma ocean (i.e. urKREEP). Until now, the only sample-based estimates of water content of KREEP-rich magmas come from measurements of OH, F, and Cl in lunar apatites, which suggest a water concentration of water content of the magma ocean would have water contents of 320 ppm for the bulk Moon and 1.4 wt % for urKREEP from plagioclase in ferroan anorthosites. Results and interpretation: NanoSIMS data from granitic clasts from Apollo sample 15405,78 show that alkali feldspar, a common mineral in K-enriched rocks, can have approx. 20 ppm of water, which implies magmatic water contents of approx. 1 wt % in the high-silica magmas. This estimate is 2 to 3 orders of magnitude higher than that estimated from apatite in similar rocks. However, the Cl and F contents of apatite in chemically similar rocks suggest that these melts also had high Cl/F ratios, which leads to spuriously low water estimates from the apatite. We can only estimate the minimum water content of urKREEP (+ bulk Moon) from our alkali feldspar data because of the unknown amount of degassing that led to the formation of the granites. Assuming a reasonable 10 to 100 times enrichment of water from urKREEP into the granites produces an estimate of 100-1000 ppm of water for the urKREEP reservoir. Using the modeling of and the 100-1000 ppm of water in urKREEP suggests a minimum bulk silicate Moon water content between 2 and 20 ppm. However, hydrogen loss was likely very significant in the evolution of the lunar mantle. Conclusions: Lunar granites

  20. Calcium silicate hydrate: Crystallisation and alkali sorption

    International Nuclear Information System (INIS)

    Homogeneous single C-S-H gels has been prepared for the investigation of alkali binding potential and crystallisation. A distribution coefficient, Rd, was introduced to express the partition of alkali between solid and aqueous phases at 25 deg. C. Rd is independent of alkali hydroxide concentration and depends only on Ca:Si ratio over wide ranges of alkali concentration. The trend of numerical values of Rd indicates that alkali bonding into the solid improves as its Ca:Si ratio decreases. Reversibility is demonstrated, indicating a possibility of constant Rd value of the material. Al has been introduced to form C-A-S-H gels and their alkali sorption properties also determined. Al substituted into C-S-H markedly increases Rd, indicating enhancement of alkali binding. However, the dependence of Rd on alkali concentration is non-ideal with composition. A two-site model for bonding is presented. Crystallisation both under saturated steam and 1 bar vapour pressure has been investigated. It has been shown that heat treatment by saturated steam causes crystallisation of gels. The principal minerals obtained were (i) C-S-H gel and Ca(OH)2 at -55 deg. C, (ii) 1.1 nm tobermorite, jennite and afwillite at 85 -130 deg. C, and (iii) xonotlite, foshagite and hillebrandite at 150-180 deg. C. Properties of crystalline C-S-H were also reported for reversible phase transformation, pH conditioning ability, seeding effect and solubility. At 1 bar pressure, crystallisation is slower than in saturated steam due to lower water activity. Tobermorite-like nanodomains develop during reaction at low Ca/Si ratios. In some Ca-rich compositions, Ca(OH)2 is exsolved and occurs as nano-sized crystallites. (author)

  1. Versatile fuel cleanup system based on palladium permeation and vapor electrolysis

    International Nuclear Information System (INIS)

    Some variations and extensions of a Fuel Cleanup System based on the combination of palladium diffuser and a vapor electrolysis cell were studied to improve the flexibility to accept broader range of flow rate, gas contents and operation modes. Processing of inert gas - CH4, H2, He2O mixtures in a closed loop showed satisfactory detritiation, with the processing of methane by catalytic steam reforming and oxidation, and electrolytic oxidation. The decomposition of hydrocarbon on the anode side of the ceramic electrolysis cell was tested to study the feasibility as an oxidizer. The zirconia ceramic membrane with Pt electrode are tested with methane at the anode for oxidation, and water vapor on the cathode for reduction. The cell converted methane to carbon dioxide and vapor with high efficiency and simultaneously decomposed water vapor to hydrogen. This application of the cell simplifies the process, and eliminates the use of catalyst and oxygen gas. A versatile fuel cleanup that eliminates most of previous concerns and improves the performance is proposed. 7 refs., 5 figs., 1 tab

  2. Composite membranes for alkaline electrolysis based on polysulfone and mineral fillers

    Science.gov (United States)

    Burnat, Dariusz; Schlupp, Meike; Wichser, Adrian; Lothenbach, Barbara; Gorbar, Michal; Züttel, Andreas; Vogt, Ulrich F.

    2015-09-01

    Mineral-based membranes for high temperature alkaline electrolysis were developed by a phase inversion process with polysulfone as binder. The long-term stability of new mineral fillers: wollastonite, forsterite and barite was assessed by 8000 h-long leaching experiments (5.5 M KOH, 85 °C) combined with thermodynamic modelling. Barite has released only 6.22 10-4 M of Ba ions into the electrolyte and was selected as promising filler material, due to its excellent stability. Barite-based membranes, prepared by the phase inversion process, were further studied. The resistivity of these membranes in 5.5 M KOH was investigated as a function of membrane thickness and total porosity, hydrodynamic porosity as well as gas purities determined by conducting electrolysis at ambient conditions. It was found that a dense top layer resulting from the phase inversion process, shows resistivity values up to 451.0 ± 22 Ω cm, which is two orders of magnitude higher than a porous bulk membrane microstructure (3.89 Ω cm). Developed membranes provided hydrogen purity of 99.83 at 200 mA cm-2, which is comparable to previously used chrysotile membranes and higher than commercial state-of-the-art Zirfon 500utp membrane. These cost-effective polysulfone - barite membranes are promising candidates as asbestos replacement for commercial applications.

  3. Study and modelling of an industrial plant for hydrogen production by High Temperature Steam Electrolysis

    International Nuclear Information System (INIS)

    HTSE field (High Temperature Steam Electrolysis) is moving from the research phase to development phase. It's now necessary to prove and to possibly improve the technology competitiveness. Therefore we need a tool able to allow communication between hydrogen producers and electrolysis cell stack designers. Designers seek where their efforts have to focus, for example by searching what are the operating best conditions for HTSE (voltage, temperature). On the contrary, the producer wants to choose the most suitable stack for its needs and under the best conditions: hydrogen has to be produced at the lowest price. Two main constraints have been identified to reach this objective: the tool has to be inserted into a process simulation software and needs to be representative of the cell and stack used technology. These constraints are antagonistic. Making an object model in a process simulation usually involves a highly simplified representation of it. To meet these constraints, we have built a model chain starting from the electrode models and leading to a representative model of the HTSE technology used process. Work and added value of this thesis mainly concern a global and local energy optimization approach. Our model allows at each scale an appropriate analysis of the main phenomena occurring in each object and a quantification of the energy and economic impacts of the technology used. This approach leads to a tool able to achieve the technical and economic optimization of a HTSE production unit. (author)

  4. HYDROGEN GENERATION FROM ELECTROLYSIS - REVISED FINAL TECHNICAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    IBRAHIM, SAMIR; STICHTER, MICHAEL

    2008-07-31

    DOE GO13028-0001 DESCRIPTION/ABSTRACT This report is a summary of the work performed by Teledyne Energy Systems to understand high pressure electrolysis mechanisms, investigate and address safety concerns related to high pressure electrolysis, develop methods to test components and systems of a high pressure electrolyzer, and produce design specifications for a low cost high pressure electrolysis system using lessons learned throughout the project. Included in this report are data on separator materials, electrode materials, structural cell design, and dissolved gas tests. Also included are the results of trade studies for active area, component design analysis, high pressure hydrogen/oxygen reactions, and control systems design. Several key pieces of a high pressure electrolysis system were investigated in this project and the results will be useful in further attempts at high pressure and/or low cost hydrogen generator projects. An important portion of the testing and research performed in this study are the safety issues that are present in a high pressure electrolyzer system and that they can not easily be simplified to a level where units can be manufactured at the cost goals specified, or operated by other than trained personnel in a well safeguarded environment. The two key objectives of the program were to develop a system to supply hydrogen at a rate of at least 10,000 scf/day at a pressure of 5000psi, and to meet cost goals of $600/ kW in production quantities of 10,000/year. On these two points TESI was not successful. The project was halted due to concerns over safety of high pressure gas electrolysis and the associated costs of a system which reduced the safety concerns.

  5. Removal of heavy metals from fly ash leachate using combined bioelectrochemical systems and electrolysis

    International Nuclear Information System (INIS)

    Highlights: • Heavy metals removal from MSWI fly ash with BES and electrolysis was confirmed. • 98.5% of Cu(II), 95.4% of Zn(II) and 98.1% of Pb(II) removal were achieved in reactors. • BESs can remove some heavy metals in fly ash with energy saving. -- Abstract: Based on environmental and energetic analysis, a novel combined approach using bioelectrochemical systems (BES) followed by electrolysis reactors (ER) was tested for heavy metals removal from fly ash leachate, which contained high detectable levels of Zn, Pb and Cu according to X-ray diffraction analysis. Acetic acid was used as the fly ash leaching agent and tested under various leaching conditions. A favorable condition for the leaching process was identified to be liquid/solid ratio of 14:1 (w/w) and leaching duration 10 h at initial pH 1.0. It was confirmed that the removal of heavy metals from fly ash leachate with the combination of BESs and ER is feasible. The metal removal efficiency was achieved at 98.5%, 95.4% and 98.1% for Cu(II), Zn(II), and Pb(II), respectively. Results of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) indicated that Cu(II) was reduced and recovered mainly as metal Cu on cathodes related to power production, while Zn(II) and Pb(II) were not spontaneously reduced in BESs without applied voltage and basically electrolyzed in the electrolysis reactors

  6. Efficient treatment of azo dye containing wastewater in a hybrid acidogenic bioreactor stimulated by biocatalyzed electrolysis.

    Science.gov (United States)

    Wang, Hong-Cheng; Cheng, Hao-Yi; Wang, Shu-Sen; Cui, Dan; Han, Jing-Long; Hu, Ya-Ping; Su, Shi-Gang; Wang, Ai-Jie

    2016-01-01

    In this study, a novel scaled-up hybrid acidogenic bioreactor (HAB) was designed and adopted to evaluate the performance of azo dye (acid red G, ARG) containing wastewater treatment. Principally, HAB is an acidogenic bioreactor coupled with a biocatalyzed electrolysis module. The effects of hydraulic retention time (HRT) and ARG loading rate on the performance of HAB were investigated. In addition, the influent was switched from synthetic wastewater to domestic wastewater to examine the key parameters for the application of HAB. The results showed that the introduction of the biocatalyzed electrolysis module could enhance anoxic decolorization and COD (chemical oxygen demand) removal. The combined process of HAB-CASS presented superior performance compared to a control system without biocatalyzed electrolysis (AB-CASS). When the influent was switched to domestic wastewater, with an environment having more balanced nutrients and diverse organic matters, the ARG, COD and nitrogen removal efficiencies of HAB-CASS were further improved, reaching 73.3%±2.5%, 86.2%±3.8% and 93.5%±1.6% at HRT of 6 hr, respectively, which were much higher than those of AB-CASS (61.1%±4.7%, 75.4%±5.0% and 82.1%±2.1%, respectively). Moreover, larger TCV/TV (total cathode volume/total volume) for HAB led to higher current and ARG removal. The ARG removal efficiency and current at TCV/TV of 0.15 were 39.2%±3.7% and 28.30±1.48 mA, respectively. They were significantly increased to 62.1%±2.0% and 34.55±0.83 mA at TCV/TV of 0.25. These results show that HAB system could be used to effectively treat real wastewater. PMID:26899658

  7. Development of a solid polymer electrolyte electrolysis cell module and ancillary components for a breadboard water electrolysis system

    Science.gov (United States)

    Porter, F. J., Jr.

    1972-01-01

    Solid polymer electrolyte technology in a water electrolysis system along with ancillary components to generate oxygen and hydrogen for a manned space station application are considered. Standard commercial components are utilized wherever possible. Presented are the results of investigations, surveys, tests, conclusions and recommendations for future development efforts.

  8. Geochemical Trace of Silicon Isotopes of Intrusions and Ore Veins Related to Alkali-rich Porphyry Deposits in Western Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    LIU Xianfan; YANG Zhengxi; LIU Jiaduo; WU Dechao; ZHANG Chenjiang; LI Youguo

    2004-01-01

    Western Yunnan is the well-known polymetallic province in China. It is characterized by copper-gold mineralization related to Cenozoic alkali-rich porphyry. This paper analyzes the silicon isotope data obtained from four typical alkali-rich porphyry deposits based on the dynamic fractionation principle of silicon isotope. The study shows that the ore materials should originate mainly from alkali-rich magmas, together with silicon-rich mineralizing fluids.The process of mineralization was completed by auto-metasomatism, i.e. silicon-rich mineralizing fluids (including alkali-rich porphyry and wall-rock strata) replaced and altered the country rocks and contaminated with crustal rocks during the crystallization of alkali-rich magmas. Such a process is essentially the continuance of the metasomatism of mantle fluids in crust's mineralization. This provides important evidence of silicon isotopic geochemistry for better understanding the mineralization of the Cenozoic alkali-rich porphyry polymetallic deposits

  9. Inorganic ion exchangers-fillers and modifiers of perfluor-polymer membranes, applicable in chlor-alkali electrolysis

    International Nuclear Information System (INIS)

    The possibility of modification of perfluor-polymer sulfonate membranes by oxyhydrate inorganic ion exchangers is studied. Study included searching of different ways to combine the inorganic ion exchanger and perfluor-polymer, revealing of modifying effect. It was defined that insertion by specific way selected inorganic ion exchanger decreases possibility of membrane to absorb water, increases electro conductivity of membrane in NaCl solutions.

  10. Alkali Metal Variation and Twisting of the FeNNFe Core in Bridging Diiron Dinitrogen Complexes.

    Science.gov (United States)

    McWilliams, Sean F; Rodgers, Kenton R; Lukat-Rodgers, Gudrun; Mercado, Brandon Q; Grubel, Katarzyna; Holland, Patrick L

    2016-03-21

    Alkali metal cations can interact with Fe-N2 complexes, potentially enhancing back-bonding or influencing the geometry of the iron atom. These influences are relevant to large-scale N2 reduction by iron, such as in the FeMoco of nitrogenase and the alkali-promoted Haber-Bosch process. However, to our knowledge there have been no systematic studies of a large range of alkali metals regarding their influence on transition metal-dinitrogen complexes. In this work, we varied the alkali metal in [alkali cation]2[LFeNNFeL] complexes (L = bulky β-diketiminate ligand) through the size range from Na(+) to K(+), Rb(+), and Cs(+). The FeNNFe cores have similar Fe-N and N-N distances and N-N stretching frequencies despite the drastic change in alkali metal cation size. The two diketiminates twist relative to one another, with larger dihedral angles accommodating the larger cations. In order to explain why the twisting has so little influence on the core, we performed density functional theory calculations on a simplified LFeNNFeL model, which show that the two metals surprisingly do not compete for back-bonding to the same π* orbital of N2, even when the ligand planes are parallel. This diiron system can tolerate distortion of the ligand planes through compensating orbital energy changes, and thus, a range of ligand orientations can give very similar energies. PMID:26925968

  11. pH dependency of hydrogen fermentation from alkali-pretreated sludge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Batch tests were carried out to study the possibility of hydrogen production from alkali-pre- treated sludge without seed and the pH dependency of hydrogen fermentation from alkali-pretreated sludge. Experimental results showed that the sewage sludge with alkali-pretreatment could be successfully applied to biologically producing hydrogen without seed and extra-feed. The results also showed that the initial pH value of sewage sludge was an important factor throughout the hydrogen fermentation of alkali-pretreated sludge. The maximum hydrogen yield was obtained at initial pH value of 11.0 (14.4 mL·g VS-1). The hydrogen yield of alkali-pretreated sludge at alkaline initial pH value was much higher than that of acidic or neutral initial pH value. The optimal pH value of hydrogen production from alkali- pretreated sludge was approximately 9.5. The consumption of hydrogen could be inhibited when the pH value of sludge was above 8.5. The change of hydrogen yield at various initial pH values was similar to that of sludge SCOD. The change of sludge pH value was slow and acetate was the major component of volatile fatty acids produced in the process of hydrogen production. The yield and the constitution of volatile fatty acids were sensitive to the initial pH value.

  12. A Control Strategy for Photovoltaic-Solid Polymer Electrolysis System Based on Surface Temperature of PV Panel

    Directory of Open Access Journals (Sweden)

    Riza Muhida

    2008-01-01

    Full Text Available Processes to produce hydrogen from solar photovoltaic powered water electrolysis using solid polymer electrolysis are reported. An alternative control of maximum power point tracking method based on analysis of PV panel’s surface Temperature for the PV-SPE system was designed and implemented. From this analysis an optimal voltage of PV can be obtained and was realized as a reference voltage of Dc-DC converter. By maintenance the output voltage of PV using the reference voltage control, the output PV can be optimized at its MPP operation. The MPPT performance and hydrogen production performance of this method have been evaluated and discussed based on the results of the experiment.

  13. High Temperature Co-electrolysis of Steam and CO2 in an SOC stack: Performance and Durability

    DEFF Research Database (Denmark)

    Chen, Ming; Høgh, Jens Valdemar Thorvald; Nielsen, Jens Ulrik;

    2012-01-01

    units can be used for co-electrolysis of steam and CO2 to produce synthesis gas (CO+H2), which can be further processed to a variety of synthetic fuels such as methane, methanol or DME [2]. Previously we have shown at stack level that Ni/YSZ electrode supported SOEC cells can be operated at 850 oC and....... The stack was operated at 800 oC and -0.75 A/cm2 with 60% conversion for a period of 1000 hours. One type of the cells showed no long term degradation but actually activation during the entire electrolysis period, while the other two types degraded. The performance and durability of the different cell...

  14. Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

    Science.gov (United States)

    Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

    2014-08-01

    The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. PMID:25104378

  15. Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

    Science.gov (United States)

    Sibille, Laurent; Dominques, Jesus A.

    2012-01-01

    The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

  16. Lithological influence of aggregate in the alkali-carbonate reaction

    International Nuclear Information System (INIS)

    The reactivity of carbonate rock with the alkali content of cement, commonly called alkali-carbonate reaction (ACR), has been investigated. Alkali-silica reaction (ASR) can also contribute in the alkali-aggregate reaction (AAR) in carbonate rock, mainly due to micro- and crypto-crystalline quartz or clay content in carbonate aggregate. Both ACR and ASR can occur in the same system, as has been also evidenced on this paper. Carbonate aggregate samples were selected using lithological reactivity criteria, taking into account the presence of dedolomitization, partial dolomitization, micro- and crypto-crystalline quartz. Selected rocks include calcitic dolostone with chert (CDX), calcitic dolostone with dedolomitization (CDD), limestone with chert (LX), marly calcitic dolostone with partial dolomitization (CD), high-porosity ferric dolostone with clays (FD). To evaluate the reactivity, aggregates were studied using expansion tests following RILEM AAR-2, AAR-5, a modification using LiOH AAR-5Li was also tested. A complementary study was done using petrographic monitoring with polarised light microscopy on aggregates immersed in NaOH and LiOH solutions after different ages. SEM-EDAX has been used to identify the presence of brucite as a product of dedolomitization. An ACR reaction showed shrinkage of the mortar bars in alkaline solutions explained by induced dedolomitization, while an ASR process typically displayed expansion. Neither shrinkage nor expansion was observed when mortar bars were immersed in solutions of lithium hydroxide. Carbonate aggregate classification with AAR pathology risk has been elaborated based on mechanical behaviours by expansion and shrinkage. It is proposed to be used as a petrographic method for AAR diagnosis to complement the RILEM AAR1 specifically for carbonate aggregate. Aggregate materials can be classified as I (non-reactive), II (potentially reactive), and III (probably reactive), considering induced dedolomitization ACR

  17. Nitrate removal and microbial analysis by combined micro-electrolysis and autotrophic denitrification.

    Science.gov (United States)

    Xing, Wei; Li, Desheng; Li, Jinlong; Hu, Qianyi; Deng, Shihai

    2016-07-01

    A process combining micro-electrolysis and autotrophic denitrification (CEAD) with iron-carbon micro-electrolysis carriers was developed for nitrate removal. The process was performed using organic-free influent with a NO3(-)-N concentration of 40.0±3.0mg/L and provided an average nitrate removal efficiency of 95% in stable stages. The total nitrogen removal efficiency reached 75%, with 21% of NO3(-)-N converted into NH4(+)-N. The corresponding hydraulic retention time was 8-10h, and the optimal pH ranged from 8.5 to 9.5. Microbial analysis with high-throughput sequencing revealed that dominant microorganisms in the reactor belonged to the classes of β-, γ-, and α-Proteobacteria. The abundance of the genera Thermomonas significantly increased during the operation, comprising 21.4% and 24.1% in sludge attached to the carriers in the middle and at the bottom of the reactor, respectively. The developed CEAD achieved efficient nitrate removal from water without organics, which is suitable for practical application. PMID:27019127

  18. Commercial scale performance predictions for high-temperature electrolysis plants coupled to three advanced reactor types

    International Nuclear Information System (INIS)

    This paper presents results of system analyses that have been developed to assess the hydrogen-production performance of commercial-scale high-temperature electrolysis (HTE) plants driven by three different advanced reactor - power-cycle combinations: a high-temperature helium-cooled reactor coupled to a direct Brayton power cycle, a supercritical CO2-cooled reactor coupled to a direct recompression cycle, and a sodium-cooled fast reactor coupled to a Rankine cycle. The system analyses were performed using UniSim software. The work described in this report represents a refinement of previous analyses in that the process flow diagrams include realistic representations of the three advanced reactors directly coupled to the power cycles and integrated with the high-temperature electrolysis process loops. In addition, this report includes parametric studies in which the performance of each HTE concept is determined over a wide range of operating conditions. Results of the study indicate that overall thermal-to-hydrogen production efficiencies (based on the low heating value of the produced hydrogen) in the 45 - 50% range can be achieved at reasonable hydrogen production rates with the high-temperature helium-cooled reactor concept, 42 - 44% with the supercritical CO2-cooled reactor and about 33 - 34% with the sodium-cooled reactor. (authors)

  19. Effects of electric voltage and sodium chloride level on electrolysis of swine wastewater

    International Nuclear Information System (INIS)

    The effects of electric voltage and NaCl concentration on the removal of pollutants in swine wastewater were investigated to determine the optimum operation conditions for a designed electrolysis process. An up-flow electrolytic reactor was fabricated from Plexiglas, and one titanium anode coated with iridium oxide (IrO2) and two stainless steel cathodes were installed in it. The anode surface area was 80 cm2/L and the hydraulic retention time (HRT) was 6 h. The results indicated that the pollutant removal was highly proportional to the electric voltage and removal could be enhanced by adding NaCl. The removal efficiencies of NH4-N, soluble nitrogen (NH4-N plus NOx-N), soluble total organic carbon (STOC), and color were proportional to the NaCl level up to 0.05% NaCl level, beyond which no further enhancement in removal was observed. However, such a tendency was not observed in the case of PO4-P removal. The obtained results indicate that 7 V and 0.05% (8.56 mM) NaCl level would be the optimum conditions for the designed electrolysis process. Under these conditions, the average removal efficiencies of NH4-N, soluble nitrogen, PO4-P, STOC, and color were 99%, 94%, 59%, 64%, and 93%, respectively.

  20. Efficiency Enhancement Mechanism for Poly(3, 4-ethylenedioxythiophene):Poly(styrenesulfonate)/Silicon Nanowires Hybrid Solar Cells Using Alkali Treatment

    Science.gov (United States)

    Jiang, Yurong; Gong, Xiu; Qin, Ruiping; Liu, Hairui; Xia, Congxin; Ma, Heng

    2016-05-01

    The efficiency enhancement mechanism of the alkali-treated Si nanowire (SiNW) solar cells is discussed and analyzed in detail, which is important to control the useful photovoltaic process. All the results demonstrate that the photovoltaic performance enhancement of alkali-treated SiNW device steps from the formation of the good core-shell heterojunction, which consequently enhances the junction area, promotes fast separating and transporting of electron and hole pairs, and reduces the carrier surface combination. It also indicates that alkali treatment for SiNWs is a promising processing as an economical method for the formation of good core-shell SiNW/polymer heterojunction.

  1. Optical response of alkali metal atoms confined in nanoporous glass

    International Nuclear Information System (INIS)

    We study the influence of optical radiation on adsorption and desorption processes of alkali metal atoms confined in nanoporous glass matrices. Exposure of the sample to near-IR or visible light changes the atomic distribution inside the glass nanopores, forcing the entire system to evolve towards a different state. This effect, due to both atomic photodesorption and confinement, causes the growth and evaporation of metastable nanoparticles. It is shown that, by a proper choice of light characteristics and pore size, these processes can be controlled and tailored, thus opening new perspectives for fabrication of nanostructured surfaces. (nanoobjects)

  2. The Impact of the Source of Alkali on Sludge Batch 3 Melt Rate

    International Nuclear Information System (INIS)

    Previous Savannah River National Laboratory (SRNL) melt rate tests in support of the Defense Waste Processing Facility (DWPF) have indicated that improvements in melt rate can be achieved through an increase in the total alkali of the melter feed. Higher alkali can be attained by the use of an ''underwashed'' sludge, a high alkali frit, or a combination of the two. Although the general trend between melt rate and total alkali (in particular Na2O content) has been demonstrated, the question of ''does the source of alkali (SOA) matter?'' still exists. Therefore the purpose of this set of tests was to determine if the source of alkali (frit versus sludge) can impact melt rate. The general test concept was to transition from a Na2O-rich frit to a Na2O-deficient frit while compensating the Na2O content in the sludge to maintain the same overall Na2O content in the melter feed. Specifically, the strategy was to vary the amount of alkali in frits and in the sludge batch 3 (SB3) sludge simulant (midpoint or baseline feed was SB3/Frit 418 at 35% waste loading) so that the resultant feeds had the same final glass composition when vitrified. A set of SOA feeds using frits ranging from 0 to 16 weight % Na2O (in 4% increments) was first tested in the Melt Rate Furnace (MRF) to determine if indeed there was an impact. The dry-fed MRF tests indicated that if the alkali is too depleted from either the sludge (16% Na2O feed) or the frit (the 0% Na2O feed), then melt rate was negatively impacted when compared to the baseline SB3/Frit 418 feed currently being processed at DWPF. The MRF melt rates for the 4 and 12% SOA feeds were similar to the baseline SB3/Frit 418 (8% SOA) feed. Due to this finding, a smaller subset of SOA feeds that could be processed in the DWPF (4 and 12% SOA feeds) was then tested in the Slurry-fed Melt Rate Furnace (SMRF). The results from a previous SMRF test with SB3/Frit 418 (Smith et al. 2004) were used as the SMRF melt rate of the baseline feed. The SOA

  3. Preliminary study of synthesis gas production from water electrolysis, using the ELECTROFUEL® concept

    International Nuclear Information System (INIS)

    This paper describes preliminary work on the generation of synthesis gas from water electrolysis using graphite electrodes without the separation of the generated gases. This is an innovative process, that has no similar work been done earlier. Preliminary tests allowed to establish correlations between the applied current to the electrolyser and flow rate and composition of the generated syngas, as well as a characterisation of generated carbon nanoparticles. The obtained syngas can further be used to produce synthetic liquid fuels, for example, methane, methanol or DME (dimethyl ether) in a catalytic reactor, in further stages of a present ongoing project, using the ELECTROFUEL® concept. The main competitive advantage of this project lies in the built-in of an innovative technology product, from RE (renewable energy) power in remote locations, for example, islands, villages in mountains as an alternative for energy storage for mobility constraints. - Highlights: • Generation of synthesis gas from water electrolysis without separation of gases. • Obtained syngas: 7.7% CO; 10.3% O2 and 2.0% CO2. • Syngas can further be used to produce synthetic liquid fuels

  4. Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis

    Directory of Open Access Journals (Sweden)

    Guangzai Nong

    2015-12-01

    Full Text Available Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas and 52.1 g of biomass solids. Therefore, the recovery ratios of elemental sodium and biomass solids are 80.4% and 76%, respectively. Treating black liquor by electrolysis is an environmentally friendly technology that can, in particular, be an alternative process in addressing the environmental issues of pulping waste liquor to the small-scale mills without black liquor recovery.

  5. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor

    International Nuclear Information System (INIS)

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with ω1/2 (ω: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH4Cl concentration was 53.46 g L-1 and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min-1. Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.

  6. Development of Hydrogen Electrodes for Alkaline Water Electrolysis

    DEFF Research Database (Denmark)

    Kjartansdóttir, Cecilía Kristín

    gas based infrastructure. Alkaline water electrolysis (AWE) is the current standard (stat of the art) for industrial large-scale water electrolysis systems. One of the main criteria for industrial AWE is efficient and durable electrodes. The aim of the present PhD study was to develop electrode...... nickel hydrides in electrode metal lattice. The material degradation was considerably more severe at the anode compared to the cathode. The durability single-cell measurements indicate no deactivation of electrodes after shut-downs. Microstructure investigations on the PVD Al-Ni diffusion couples at 610......Ni3 phase. The diffusion mechanism can be the key to good properties of the developed PVD Al/Ni electrodes. Electrodes produced with shorter time of diffusion, 10-30 minutes, are found to be more prone to alkaline aluminium leaching and only 4-5 wt.% of aluminium residue is found in the leached...

  7. Neutron emission during Pd-D2O electrolysis

    International Nuclear Information System (INIS)

    A clear correlation has been found between neutron counting and the pulsation of an electrolysis current obtained with different Pd cathodes (rolled and wire) in D2O. Different spectra as a function of time synchronized with the electrolysis current of Pd-D2O and Pd-H2O are presented, all in identical conditions. Measurements in Pd-D2O lack the (statistically significant) synchronic increments in counting which are observed when the electrolite used is D2O. On the hypothesis that the observed neutrons are originated in Deuteron fusion with a branching ratio 0.5, the obtained countings correspond to a fusion rate of approximately 0.5 fusions/second. (Author)

  8. Alkali roasting of bomar ilmenite: rare earths recovery and physico-chemical changes

    Directory of Open Access Journals (Sweden)

    Sanchez-Segado Sergio

    2014-11-01

    (FeTiO3 is presented as a process route for integrated beneficiation of the mineral for rutile-rich phase and rare earth oxides; the latter is released as a consequence of physical changes in the ilmenite matrix, during the water leaching after roasting. The oxidative alkali roasting transforms ilmenite mineral into water-insoluble alkali titanate and water-soluble ferrite. After roasting the insoluble alkali titanate is separated from rare-earth oxide mixture in colloidal form and water-soluble ferrite. Further leaching of alkali titanate is carried out with oxalic (0.3M and ascorbic (0.01M acid solution which removes the remaining Fe2+ ions into the leachate and allows precipitation of high-purity synthetic rutile containing more than 95% TiO2. Iron is removed as iron oxalate. The physico-chemical changes occurred during the roasting and leaching processes are reported by comparing the role of alkali on the roasting process and product morphologies formed.

  9. Aluminium Electrolysis with Fe-Ni-Al2O3 Inert Anodes at 850 °C

    Science.gov (United States)

    Shi, Zhongning; Junli, Junli; Gao, Bingliang; Hu, Xianwei; Wang, Zhaowen

    2011-06-01

    Fe-Ni-Al2O3 cermet materials were prepared, and the electrolysis with these anodes were performed in cryolite-based electrolyte consisted of 44NaF-40AlF3-8NaCl-5CaF2-3Al2O3(wt%) at 850 °C. The purity of produced aluminium is 97-98%, while the calculated anodic corrosion rate is 18.2 mm/a-24.0 mm/a. The EPMA analysis showed that there is an oxide scale consisting of Fe2O3 and FeAl2O4 on the anode working surface. The homeostasis of dissolution and formation of oxide scale makes the thickness of the oxide scale and the cell voltage stable within a certain range. The dissolution of oxide scale results in the presence of FeF3 in the electrolyte. By analysis of the corrosion process, it shows that low temperature, high alumina concentration and low CR electrolysis is preferred for using Fe-Ni-Al2O3 inert anodes for aluminium electrolysis.

  10. Characteristics of particulate emissions from aluminium electrolysis cells

    OpenAIRE

    Gaertner, Heiko

    2013-01-01

    Modern sampling and analysis techniques were applied to study the morphology and composition of pot exhaust particles from aluminium smelters. In this study the total spectrum of pot exhaust particles from prebake electrolysis cells was sampled on filters and in a standard cyclone. Application of a cascade impactor allowed for fractionation of raw gas dust into 12 fractions with particle diameters in the range from approximately 7 nm to 10 μm. The performed experiments demonstrated that the p...

  11. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    OpenAIRE

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the ...

  12. Solid Oxide Electrolysis Cells: Degradation at High Current Densities

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Traulsen, Marie Lund; Hauch, Anne; Ebbesen, Sune; Mogensen, Mogens Bjerg

    2010-01-01

    The degradation of Ni/yttria-stabilized zirconia (YSZ)-based solid oxide electrolysis cells operated at high current densities was studied. The degradation was examined at 850°C, at current densities of −1.0, −1.5, and −2.0 A/cm2, with a 50:50 (H2O:H2) gas supplied to the Ni/YSZ hydrogen electrode...

  13. Application of mercury cathode electrolysis to fission-product separation

    International Nuclear Information System (INIS)

    A method involving controlled potential mercury cathode electrolysis has been developed to separate fission products. It allows the radiochemical determination of Ag, Cd, Pd, Rh, Ru, Sn, Te, Sb and Mo from solutions of fission products highly concentrated in mineral salts. The general procedure consists in three main steps: electrolytic amalgam generation, destruction of amalgams and ultimate purification of elements by other means. Electrolytic operations last about five hours. Chemical yields lie between 10 per cent and 70 per cent. (authors)

  14. Theoretical investigation on the alkali-metal doped BN fullerene as a material for hydrogen storage

    International Nuclear Information System (INIS)

    Graphical abstract: First-principles calculations have been used to investigate hydrogen adsorption on alkali atom doped B36N36 clusters. Adsorption of alkali atoms involves a charge transfer process, creating positively-charged alkali atoms and this polarizes the H2 molecules and increases their binding energy. The maximum hydrogen storage capacity of Li doped BN fullerene is 8.9 wt.% in which 60 hydrogen atoms were chemisorbed and 12 H2 were adsorbed in molecular form. - Abstract: First-principles calculations have been used to investigate hydrogen adsorption on alkali atom doped B36N36 clusters. The alkali atom adsorption takes place near the six tetragonal bridge sites available on the cage, thereby avoiding the notorious clustering problem. Adsorption of alkali atoms involves a charge transfer process, creating positively charged alkali atoms and this polarizes the H2 molecules thereby, increasing their binding energy. Li atom has been found to adsorb up to three hydrogen molecules with an average binding energy of 0.189 eV. The fully doped Li6B36N36 cluster has been found to hold up to 18 hydrogen molecules with the average binding energy of 0.146 eV. This corresponds to a gravimetric density of hydrogen storage of 3.7 wt.%. Chemisorption on the Li6B36N36 has been found to be an exothermic reaction, in which 60 hydrogen atoms chemisorbed with an average chemisorption energy of -2.13 eV. Thus, the maximum hydrogen storage capacity of Li doped BN fullerene is 8.9 wt.% in which 60 hydrogen atoms were chemisorbed and 12 hydrogen molecules were adsorbed in molecular form.

  15. Superconductivity in alkali-doped C60

    International Nuclear Information System (INIS)

    Highlight: • Superconductivity in alkali-doped C60 (A3C60) is well described by an s-wave state produced by phonon mediated pairing. • Moderate coupling of electrons to high-frequency shape-changing intra-molecular vibrational modes produces transition temperatures up to 33 K in single-phase material. • The good understanding of pairing in A3C60 offers a paradigm for the development of new superconducting materials. - Abstract: Superconductivity in alkali-doped C60 (A3C60, A = an alkali atom) is well described by an s-wave state produced by phonon mediated pairing. Moderate coupling of electrons to high-frequency shape-changing intra-molecular vibrational modes produces transition temperatures (Tc) up to 33 K in single-phase material. The good understanding of pairing in A3C60 offers a paradigm for the development of new superconducting materials

  16. Production of hydrogen using composite membrane in PEM water electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Santhi priya, E.L.; Mahender, C.; Mahesh, Naga; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally, Hyderabad-500 085, A.P (India); Anjaneyulu, Y. [Director, TLGVRC, JSU Box 18739, JSU, Jackson, MS 32917-0939 (United States)

    2012-07-01

    Electrolysis of water is the best known technology till today to produce hydrogen. The only practical way to produce hydrogen using renewable energy sources is by proton exchange membrane (PEM) water electrolysis. The most commonly used PEM membrane is Nafion. Composite membrane of TiO2 is synthesized by casting method using Nafion 5wt% solution. RuO2 is used as anode and 10 wt% Pd on activated carbon is used as cathode in the water electrolyser system. The performance of this Composite membrane is studied by varying voltage range 1.8 to 2.6V with respect to hydrogen yield and at current density 0.1, 0.2, 0.3, 0.4, and 0.5(A cm-2). This Composite membrane has been tested using in-house fabricated single cell PEM water electrolysis cell with 10cm2 active area at temperatures ranging from 30,45,65 850c and at 1 atmosphere pressure.

  17. Tritium separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    Use of bipolar electrolysis with countercurrent electrolyte flow to separate hydrogen isotopes was investigated for the removal of tritium from light water effluents or from heavy water moderator. Deuterium-tritium and protium-tritium separation factors occurring on a Pd-25% Ag bipolar electrode were measured to be 2.05 to 2.16 and 11.6 to 12.4 respectively, at current densities between 0.21 and 0.50 A cm-2, and at 35 to 900C. Current densities up to 0.3 A cm-2 have been achieved in continuous operation, at 80 to 900C, without significant gas formation on the bipolar electrodes. From the measured overvoltage at the bipolar electrodes and the electrolyte conductivity the power consumption per stage was calculated to be 3.0 kwh/kg H2O at 0.2 A cm-2 and 5.0 kwh/kg H2O at 0.5 A cm-2 current density, compared to 6.4 and 8.0 kwh/kg H2O for normal electrolysis. A mathematical model derived for hydrogen isotope separation by bipolar electrolysis, i.e., for a square cascade, accurately describes the results for protium-tritium separation in two laboratory scale, multistage experiments with countercurrent electrolyte flow; the measured tiritum concentration gradient through the cascade agreed with the calculated values

  18. High temperature steam electrolysis stack with enhanced performance and durability

    International Nuclear Information System (INIS)

    High Temperature Steam Electrolysis (HTSE) is one of the most promising ways for hydrogen production. If coupled to a CO2-free electricity and low cost heat sources, this process is liable to a high efficiency. The present study describes recent promising results obtained in terms of performance and durability in stack environment, thanks to the use of protective coatings on one hand, and of advanced cells on the other hand. As for Solid Oxide Fuel Cells, it has been demonstrated that the integration of protective coatings was mandatory to decrease the degradation rate in HTSE stacks, and that with optimized coatings, (CoMn)3O4 in the present case, the same durability as the one of the single cell tested in a ceramic housing could be reached. The type of cell was also shown to play a major role on the degradation rate. With advanced cells, degradations below 2%/kh could be reached. The higher is the current density, the higher is the degradation rate, with a mostly reversible effect. These degradation rates are close to the objectives, even if a bit higher than in SOFC mode. Finally a low-weight stack has been designed, targeting high performance and durability while reducing the cost by the use of thin interconnects. An electrochemical performance similar to the previous stack design has been obtained for a 3-cell stack (-1 A/cm2) at 1.3 V at 800 degrees C), with degradation rates below 3%/1000 h in the testing conditions. The thermal cyclability of stacks has been demonstrated, from 800 degrees C to 20 degrees C, as well as electrical load cycling. The results showed that the HTSE stacks considered in the present study can cycle very rapidly, and that the cycles considered do not induce any degradation. Therefore it can be concluded that these results makes HTSE technology getting closer to the objectives of performance, durability, thermal and electrical cyclability and cost, and that HTSE is a candidate to produce hydrogen as a mean to store renewable

  19. Electrolysis of water on (oxidized) metal surfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Logadottir, Ashildur; Nørskov, Jens Kehlet

    Density functional theory calculations are used as the basis for an analysis of the electrochemical process, where by water is split to form molecular oxygen and hydrogen. We develop a method for obtaining the thermochemistry of the electrochemical water splitting process as a function of the bia...

  20. Electrocatalysis in Water Electrolysis with Solid Polymer Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Rasten, Egil

    2001-10-01

    Development and optimization of the electrodes in a water electrolysis system using a polymer membrane as electrolyte have been carried out in this work. A cell voltage of 1.59 V (energy consumption of about 3.8 kWh/Nm{sub 3} H{sub 2}) has been obtained at practical operation conditions of the electrolysis cell (10 kA . m2, 90{sup o}C) using a total noble metal loading of less than 2.4 mg.cm{sub 2} and a Nafion -115 membrane. It is further shown that a cell voltage of less than 1.5 V is possible at the same conditions by combination of the best electrodes obtained in this work. The most important limitation of the electrolysis system using polymer membrane as electrolyte has proven to be the electrical conductivity of the catalysts due to the porous backing/current collector system, which increases the length of the current path and decreases the cross section compared to the apparent one. A careful compromise must therefore be obtained between electrical conductivity and active surface area, which can be tailored by preparation and annealing conditions of the metal oxide catalysts. Anode catalysts of different properties have been developed. The mixed oxide of Ir-Ta (85 mole% Ir) was found to exhibit highest voltage efficiency at a current density of 10 kA.m{sub 2} or below, whereas the mixed oxide of Ir and Ru (60-80 mole% Ir) was found to give the highest voltage efficiency for current densities of above 10 kA.m{sub 2}. Pt on carbon particles, was found to be less suitable as cathode catalyst in water electrolysis. The large carbon particles introduced an unnecessary porosity into the catalytic layer, which resulted in a high ohmic drop. Much better voltage efficiency was obtained by using Pt-black as cathode catalyst, which showed a far better electrical conductivity. Ru-oxide as cathode catalyst in water electrolysis systems using a polymer electrolyte was not found to be of particular interest due to insufficient electrochemical activity and too low

  1. Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities

    DEFF Research Database (Denmark)

    Tao, Youkun; Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

    2014-01-01

    process and the reaction process at the Ni-YSZ triple-phase boundaries. The performance degradation is mainly ascribed to the microstructural changes in the Ni-YSZ electrode close to the YSZ electrolyte, including percolation loss of Ni and the contact loss of Ni and YSZ electrolyte. The type of the......In this work the durability of solid oxide cells for co-electrolysis of steam and carbon dioxide (45 % H2O + 45 % CO2 + 10 % H2) at high current densities was investigated. The tested cells are Ni-YSZ electrode supported, with a YSZ electrolyte and either a LSM-YSZ or LSCF-CGO oxygen electrode. A...... oxygen electrode showed an influence to the ohmic degradation: the better performing oxygen electrode corresponded to a lower Rs increase. However, the oxygen electrode itself was found to be relative stable both with respect to the electrochemical performance and microstructure....

  2. Degradation of Methyl Orange in Water by Contact Glow Discharge Electrolysis

    Institute of Scientific and Technical Information of China (English)

    GONG Jianying; CAI Weimin

    2007-01-01

    The degradation of methyl orange in a neutral phosphate buffer solution was investigated by means of contact glow discharge electrolysis (CGDE).The methyl oranges were degraded and eventually decomposed into inorganic carbon when CGDE was conducted under the applied DC voltage of 480 V and current of ca.80 mA.As the intermediate products,some phenolic compounds were detected as well as carboxylic acids.Experimental results showed that the oxidation process followed the first-order reaction law.Based on the analysis of the ultraviolet (UV) spectra of the solution and the intermediate products from High Pressure Liquid Chromatography-Mass Spectrum (HPLC-MS),the reaction pathway was proposed.The attack of hydroxyl radicals was considered to be a key step to start the whole oxidation process.

  3. Alkali Pretreatment and Enzymatic Hydrolysis of Cattails from Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2010-01-01

    Full Text Available Problem statement: To date, production of liquid fuel, particularly ethanol, has only been economically feasible from food crops that are high in sugar and starch. However, the use of arable land for fuel rather than for food production and the use of a food source for fuel rather than as food have created issues in prices and availability of traditional foods and feed. The use of cattails to produce biofuel will add value to land and will also reduce emissions of greenhouse gases by replacing petroleum products. Approach: In order to investigate the feasibility of converting cattails into cellulosic ethanol, an alkali (NaOH pretreatment process was studied using cattails from constructed wetlands on a North Carolina A and T Farm based on NaOH concentration and enzyme loading. Results: The alkali pretreatment method was able to effectively increase enzymatic digestibility of cattail cellulose; nearly 78% of the cellulose from raw cattails was converted to fermentable glucose in 48 h using a cellulase loading of 60 FPU g-1 glucan. About 25.5, 37.4, 38.4, 42.4 and 55.9% of the lignin was removed with pretreatment in 0.5, 1, 2, 3 and 4% NaOH, respectively. The yeast Saccharomyces cerevisiae (ATCC 24858 was able to ferment the sugars released by cattail cellulose. Conclusion: The overall effectiveness of alkali pretreatment was a function of NaOH concentration and enzyme loading. NaOH concentrations in the range of 1-2% are recommended for the pretreatment of cattails. For cattails pretreated with 4% NaOH, no significant change in digestibility occurred when enzyme loading was increased beyond 15 FPU g-1 glucan. It is recommended that further studies be carried out using cattails as a feedstock for biofuels, especially to optimize the economics of pretreatment processes for cattails in terms of energy input, enzyme loading, glucose yield and xylose yield.

  4. Heavy water in the context of hydrogen economy. Prospects for cheaper production by water electrolysis

    International Nuclear Information System (INIS)

    Hydrogen is an extremely important material. It is commonly used in many industrial processes. It can also be used as the key medium in 'hydrogen energy philosophy' due to its unique energetic properties (production for storage, gas-line transport). Its heavy isotopes, deuterium (D) and tritium (T), are very important nuclear materials. Deuterium, in the form of heavy water, is an excellent moderator in fission reactors, while both D and T are now seen as fuel components in fusion reactors in the future. Thus, improvements of production processes for hydrogen and its isotopes are always actual. Electrolysis (sometimes in combination with other methods) is often used for heavy water production or re-enrichment or for tritium removal from 'nuclear waters', mostly because of high D/H (T/H, T/D) isotope separation factors, although the electrolysis consumes great amounts of energy (about 4.5 to 5 kWh/m3 H2 in industrial electrolyzers). There were various attempts to improve this process: zero-gap cell geometry, development of new diaphragm materials, development of new electrocatalytic materials for electrodes, using so-called ionic activators etc. We investigated the use of catalytic cathode materials made from hypo-hyper-d-electronic combinations of transition metals as well as in situ activation of electrodes. Many intermetallic combinations were tried. Two types of ionic activators were used: tris-(ethylenediamine)-Co(III)-chloride complex and tris-(trimethylenediamine)-Co(III)-chloride complex. Some significant increases of the separation factors were obtained. Dependence of isotope enrichment on the amount of water that must be electrolysed for was estimated for different values of the separation factor. It was concluded that this a good way to increase the efficiency of the process by achieving an energy saving and an increase of the separation factors simultaneously. The method is discussed in a context that assumes heavy water as a by-product of the hydrogen

  5. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

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

    2012-01-01

    Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared by...

  6. Alkali metals in fungi of forest soil

    International Nuclear Information System (INIS)

    The high affinity of forest soil fungi for alkali metals such as potassium, rubidium, caesium as well as radiocaesium is shown and discussed. Good positive correlation was found between K: Rb concentration ratios in soil and in fungi, when correlation between K: Cs concentration ratios was less pronounced. (LN)

  7. Contributions to the mixed-alkali effect in molecular dynamics simulations of alkali silicate glasses

    OpenAIRE

    Lammert, Heiko; Heuer, Andreas

    2005-01-01

    The mixed-alkali effect on the cation dynamics in silicate glasses is analyzed via molecular dynamics simulations. Observations suggest a description of the dynamics in terms of stable sites mostly specific to one ionic species. As main contributions to the mixed--alkali slowdown longer residence times and an increased probability of correlated backjumps are identified. The slowdown is related to the limited accessibility of foreign sites. The mismatch experienced in a foreign site is stronge...

  8. SISGR-Fundamental Experimental and Theoretical Studies on a Novel Family of Oxide Catalyst Supports for Water Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumta, Prashant [University of Pittsburgh

    2014-10-03

    potentially be preferred as OER electro-catalysts for PEM electrolysis. The excellent performance of the catalysts coupled with its robustness would make them great candidates for contributing to significant reduction in the overall capital costs of PEM based water electrolyzers. This s.thesis provides a detailed fundamental study of the synthesis, materials, characterization, theoretical studies and detailed electrochemical response and potential mechanisms of these novel electro-catalysts for OER processes.

  9. Direct observation of bi-alkali antimonide photocathodes growth via in operando x-ray diffraction studies

    OpenAIRE

    M. Ruiz-Osés; Schubert, S.; Attenkofer, K.; Ben-Zvi, I.; Liang, X; Muller, E; Padmore, H; Rao, T.; T. Vecchione; Wong, J; Xie, J.; Smedley, J.

    2014-01-01

    Alkali antimonides have a long history as visible-light-sensitive photocathodes. This work focuses on the process of fabrication of the bi-alkali photocathodes, K2CsSb. In-situ synchrotron x-ray diffraction and photoresponse measurements were used to monitor phase evolution during sequential photocathode growth mode on Si(100) substrates. The amorphous-to-crystalline transition for the initial antimony layer was observed at a film thickness of 40 Å . The antimony crystalline structure dissolv...

  10. Research Progresses of New Type Alkali-activated Cementitious Material Catalyst

    Directory of Open Access Journals (Sweden)

    ZHANG Yao-Jun, YANG Meng-Yang, KANG Le, ZHANG Li, ZHANG Ke

    2016-03-01

    Full Text Available Alkali-activated solid aluminosilicate-based cementitious material is one of prospective research fields of advanced inorganic non-metallic materials. Its classification, preparation process, formation mechanism, and potential applications are reviewed in this paper. It is considered that its microstructure and chemical characteristics intensively depend on the raw materials and synthesis conditions. Geopolymers derive from alkali-activated metakaolin or fly ash with low calcium content, while the amorphous calcium silicate hydrate (C-S-H gels root in the chemical-activated solid wastes of granular blast furnace slag, steel slag and other solid aluminosilicate wastes with high calcium contents. Even though durability of alkali-activated cementitious materials as the building structure materials has been widely studied in the past decades, the intrinsic brittleness still restricts their applications in the field of civil and building engineering. Therefore, exploration of a new applied approach is by far the best option. In recent years, many researches report that the alkali-activated cementitious materials are used as novel precursors and catalysts for some kinds of heterogeneous reactions. The latest research progresses on alkali-activated cementitious material-based catalysts are discussed.

  11. Electrolysis of H2O and CO2 in an oxygen-ion conducting solid oxide electrolyzer with a La0.2Sr0.8TiO3+δ composite cathode

    Science.gov (United States)

    Li, Shisong; Li, Yuanxin; Gan, Yun; Xie, Kui; Meng, Guangyao

    2012-11-01

    Solid oxide electrolyzers have attracted a great deal of interest in recent years because they can convert electrical energy into chemical energy with high efficiency. Ni/YSZ cathodes are generally utilized for high temperature electrolysis of H2O and CO2 in oxygen-ion conducting solid oxide electrolyzers; however, such electrodes can only operate under reducing conditions. In an atmosphere without a flow of reducing gas, cathodes based on La0.2Sr0.8TiO3+δ (LST) are a promising alternative. Solid Oxide Electrolyzers with LST cathodes without pre-reduction were used at 700 °C for the electrolysis of 3%H2O/97%N2 and 100%CO2, and promising polarization impedance data were obtained in both atmospheres. The electrochemical results indicated that the electrochemical reduction of the La0.2Sr0.8TiO3+δ cathode was the main process at low electrical voltages, while the electrolysis was the main process at high voltages because ion transportation in the electrolyte limited the overall efficiency. The electrolysis of H2O was determined to be more efficient than the electrolysis of CO2 under the same conditions. The Faraday efficiencies of H2O and CO2 were 85.0% and 24.7%, respectively, at 700 °C and a 2 V applied potential.

  12. Removal of Mercury from chlor-alkali Industry Wastewater using Acetobacter xylinum Cellulose

    Directory of Open Access Journals (Sweden)

    A. Rezaee

    2005-01-01

    Full Text Available In this study, the removal of mercury ions by cellulose of Acetobacter xylinum was investigated in the synthetic and chlor-alkali wastewater. Biofilms of Acetobacter xylinum were grown in laboratory column bioreactors. The biofilms were continuously treated with sterile synthetic model wastewater or nonsterile, neutralized chloralkali wastewater.The extent of adsorption was studied as function of pH, adsorbent dose and contact time. Efficiency of mercury ion removal from chlor-alkali industry wastewater by aluminum sulfate and ferric chloride was also determined. Under acidic condition the adsorption of mercury by cellulose was quite low and increasing processing time more than 10min has no remarkably effect on the adsorption rate. Adsorption capacity of cellulose under dynamic condition for chlor-alkali wastewater was 65mg/µg which was less than the value (80mg/µg that obtained from batch adsorption experiments for synthetic wastewater.

  13. Development and character of gap states on alkali doping of molecular films

    International Nuclear Information System (INIS)

    Here we study the alkali metal induced effects on an ordered and aligned sexiphenyl monolayer on Cu(110) with angle-resolved UV spectroscopy (ARUPS). The caesium (Cs) induced gap states could clearly be identified by orbital tomography, a method based on ARUPS, which allows both the orbital character of these states and the molecular orientation to be determined. We show that with increasing alkali metal dose, doping proceeds in three distinct steps. Initially, Cs decouples the molecular monolayer from the substrate, with emptying of the lowest unoccupied molecular orbital (LUMO) that had been filled on hybridization with the substrate. Further Cs exposure refills the LUMO. Finally a filling of the LUMO + 1 by charge transfer from the alkali metal occurs. Remarkably, although long range order is not preserved and the molecular planes tilt away from the surface, the molecules remain aligned parallel to the [1 1-bar 0] azimuth during the whole doping process. (paper)

  14. Iron migration from the anode surface in alumina electrolysis

    Science.gov (United States)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V.; Kirik, Sergei D.

    2013-01-01

    Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF3 electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF2. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl2O4, Fe3O4, Fe2O3. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The electrolysis of alumina occurs beyond the corrosion shell. The rate limiting step in the corrosion is the electrolyte penetration through corrosion shell to the anode surface. The participation of the released oxygen in the corrosion has not been observed.

  15. A metallic seal for high-temperature electrolysis stacks

    International Nuclear Information System (INIS)

    Gas tightness over a long period of time is a real challenge in high-temperature electrolysis. The seals must indeed be able to run at high temperature between metals and brittle ceramic materials, which is a major issue to be solved. The common sealing solution relies on glass-made seals, despite their low mechanical strength at high temperature. Metallic seals have seldom been used in this field, because their stiffness and their hardness require a much higher load to achieve the appropriate tightness. In the French project ANR Pan-H/SEMIEHT, two different sealing solutions were investigated in two different locations of the GENHEPIS-G1 stack. Experiments were carried out with a glass-made seal between the cell and its ceramic support, and with metallic seals between the interconnect and the cell support, in order to seal the gas input and output as well as the cathodic chamber. An initial Garlock seal design has been optimised in order to decrease the seating load. Seals were also manufactured by Garlock. The C-shaped seals are made of two components: an Inconel-X750-made elastic inner part, and a specially profiled Fecralloy-made 'soft' outer lining. The use of Fecralloy enables the generation of an alumina thin layer, which both protects the seal and eases disassembly. In this study, these seals were tested on specific equipments and on actual stacks. It is shown that they are tight enough to achieve the electrolysis tests at 800 deg. C. Therefore a significant breakthrough in high-temperature electrolysis sealing has been achieved. It sheds new light on the actual potential of metallic seals and constitutes a basis for ongoing studies, such as another French project, namely ANR/Pan-H/EMAIL. (authors)

  16. Potential Modulated Intercalation of Alkali Cations into Metal Hexacyanoferrate Coated Electrodes

    International Nuclear Information System (INIS)

    Nickel hexacyanoferrate is a polynuclear inorganic ion intercalation material that loads (intercalates) and elutes (deintercalates) alkali cations from its structure when electrochemically reduced and oxidized, respectively. Nickel hexacyanoferrrate (NiHCF) is known to preferentially intercalate cesium over all other alkali cations, thus providing a basis for a separation scheme that can tackle DOE's radiocesium contamination problem. This program studied fundamental issues in alkalization intercalation and deintercalation in nickel hexacyanoferrate compounds, with the goal of (1) quantifying the ion exchange selectivity properties from cation mixtures, (2) enhancing ion exchange capacities, and (3) and understanding the electrochemically-switched ion exchange process (ESIX)

  17. A STUDY ON THE ADSORPTION OF LOW CONCENTRATION FREE ALKALI BY SUBACID RESIN

    Institute of Scientific and Technical Information of China (English)

    PANYufang; CHENBingren; 等

    2001-01-01

    The absorption of free alkali at low concentration by subacid resin was traced with electric conductance method,the effect of temperature on the adsorption,the activation energy of adsorption (Ea) and interaction energy(U) was studied.The result showed that,the process of low concentration alkali adsorption by subacid resin was in accordance with mechanism of monomolecular layer absorption,in addition,with the increasing of temperature,the interaction energy between adsorbate and sorbent increase,so did the surface adsorption rate(k),and linear correlation existed between interaction energy(U) and temperature(T).

  18. Study on alkali leaching of a complicated uranium-bearing magnetic concentrate

    International Nuclear Information System (INIS)

    Alkali leaching of a complicated uranium-bearing magnetic concentrate was studied. The research results showed that the uranium recovery from the concentrate leaching increased with destruction and dissolution of organic matters. It is suitable and feasible to treat the magnetic concentrate by a two-stage alkali leaching process including pre-leaching, and it is beneficial to treat the obtained product solution in the subsequent operations. It is extremely possible that the residual uranium in the leached residue is closely associated with hard-to-open davidite. So it is not reasonable economically to continue intensifying the conditions to treat the concentrate

  19. Measurement of background gas in paraffin-coated alkali vapor cells

    CERN Document Server

    Sekiguchi, Naota

    2015-01-01

    We measured the rate of velocity-changing collisions (VCCs) between alkali atoms and background gas in buffer-gas-free anti-spin-relaxation-coated cells. The average VCC rate in paraffin-coated rubidium vapor cells prepared in this work was $1 \\times 10^{6}$ s$^{-1}$, which corresponds to $\\sim$1 mm in the mean free path of rubidium atoms. This short mean free path indicates that alkali atoms do not travel freely between the cell walls. In addition, we found that a heating process known as "ripening" increases the VCC rate, and also confirmed that ripening improves the anti-relaxation performance of the coatings.

  20. High School Students' Proficiency and Confidence Levels in Displaying Their Understanding of Basic Electrolysis Concepts

    Science.gov (United States)

    Sia, Ding Teng; Treagust, David F.; Chandrasegaran, A. L.

    2012-01-01

    This study was conducted with 330 Form 4 (grade 10) students (aged 15-16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students' understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic…

  1. Production of neutron and tritium from D2O electrolysis with palladium cathode

    International Nuclear Information System (INIS)

    Anomalous neutron burst and an increase in tritium concentration were observed simultaneously from heavy water electrolysis with palladium cathode. Considered with previous experiment results, we presumed that production of neutron and tritium from D2O electrolysis depends heavily on the constitution and the state of each cathode. (author)

  2. Production of Synthetic Fuels by Co-Electrolysis of Steam and Carbon Dioxide

    DEFF Research Database (Denmark)

    Ebbesen, Sune; Graves, Christopher R.; Mogensen, Mogens Bjerg

    2009-01-01

    Co-electrolysis of H2O and CO2 was studied in solid oxide cells (SOCs) supported by nickel-/yittria-stabilized zirconia (Ni/YSZ) electrode. Polarization characterization indicates that electrochemical reduction of both CO2 and H2O occurs during co-electrolysis. In parallel with the electrochemical...

  3. Solid Oxide Electrolysis Cells: Microstructure and Degradation of the Ni/Yttria-Stabilized Zirconia Electrode

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    Solid oxide fuel cells produced at Risø DTU have been tested as solid oxide electrolysis cells for steam electrolysis by applying an external voltage. Varying the sealing on the hydrogen electrode side of the setup verifies that the previously reported passivation over the first few hundred hours...

  4. Efficiency of tritium measurement in the environmental water by electrolysis enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Koganezawa, T.; Iida, T. [Nagoya Univ., Graduate School of Engineering, Nagoya, Aichi (Japan); Sakuma, Y.; Yamanishi, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Ogata, Y. [Nagoya Univ., School of Health Sciences, Nagoya, Aichi (Japan); Tsuji, N. [Japan Air-conditioning Service Co. and Ltd., Nagoya, Aichi (Japan); Kakiuchi, M. [Gakushuin Univ., Faculty of Science, Tokyo (Japan); Satake, H. [Toyama Univ., Faculty of Science, Toyama (Japan)

    2002-06-01

    Now tritium concentration in the environmental water is 0.5-2 Bq{center_dot}L{sup -1} in Japan. Tritium concentration cannot be measured accurately by liquid scintillation method, because the minimum detectable limits of liquid scintillation method is 0.5 Bq{center_dot}L{sup -1}. Therefore, one needs to enrich tritium concentration in the environmental water. Although the most popular method for tritium enrichment is electrolysis, the electrolysis takes much time and labor for distilling sample water at before and after the electrolysis. The purpose of this study is to investigate the possibility of more convenient method for tritium measurement. The method substitutes filtration for distillation at before electrolysis and omits distillation at after electrolysis. The method enables by using the electrolysis with solid polymer electrode. We performed two kinds of experiment to confirm the possibility of the method. First, impurities eluted from electrolysis installation with ultra pure water as sample was measured. Some impurities were eluted into the sample, but they brought noneffective quenching. Secondly, we applied new method to the environmental waters. Substituting for distillation, two filtration, 0.1 {mu}m filtration and reverse osmosis method, were investigated. Impurities in the samples by the filtrations were somewhat higher than that by the distillation, they brought noneffective quenching. We, however, observed distemper of the electrolysis happened by electrolysing filtered sample. Distillation is substituted filtration at before enrichment and omitted at after enrichment, leaving the influence of quenching out of consideration. (author)

  5. Electrolysis of Water in the Secondary School Science Laboratory with Inexpensive Microfluidics

    Science.gov (United States)

    Davis, T. A.; Athey, S. L.; Vandevender, M. L.; Crihfield, C. L.; Kolanko, C. C. E.; Shao, S.; Ellington, M. C. G.; Dicks, J. K.; Carver, J. S.; Holland, L. A.

    2015-01-01

    This activity allows students to visualize the electrolysis of water in a microfluidic device in under 1 min. Instructional materials are provided to demonstrate how the activity meets West Virginia content standards and objectives. Electrolysis of water is a standard chemistry experiment, but the typical laboratory apparatus (e.g., Hoffman cell)…

  6. Efficiency of tritium measurement in the environmental water by electrolysis enrichment

    International Nuclear Information System (INIS)

    Now tritium concentration in the environmental water is 0.5-2 Bq·L-1 in Japan. Tritium concentration cannot be measured accurately by liquid scintillation method, because the minimum detectable limits of liquid scintillation method is 0.5 Bq·L-1. Therefore, one needs to enrich tritium concentration in the environmental water. Although the most popular method for tritium enrichment is electrolysis, the electrolysis takes much time and labor for distilling sample water at before and after the electrolysis. The purpose of this study is to investigate the possibility of more convenient method for tritium measurement. The method substitutes filtration for distillation at before electrolysis and omits distillation at after electrolysis. The method enables by using the electrolysis with solid polymer electrode. We performed two kinds of experiment to confirm the possibility of the method. First, impurities eluted from electrolysis installation with ultra pure water as sample was measured. Some impurities were eluted into the sample, but they brought noneffective quenching. Secondly, we applied new method to the environmental waters. Substituting for distillation, two filtration, 0.1 μm filtration and reverse osmosis method, were investigated. Impurities in the samples by the filtrations were somewhat higher than that by the distillation, they brought noneffective quenching. We, however, observed distemper of the electrolysis happened by electrolysing filtered sample. Distillation is substituted filtration at before enrichment and omitted at after enrichment, leaving the influence of quenching out of consideration. (author)

  7. Degradation of 2,4-dichlorophenol by using glow discharge electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu Quanfang [Editorial Department of the University Journal, Northwest Normal University, Lanzhou 730070 (China); Yu Jie [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Gao Jinzhang [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)]. E-mail: jzgao@nwnu.edu.cn

    2006-08-25

    Degradation of 2,4-dichlorophenol (2,4-DCP) in aqueous by glow discharge electrolysis (GDE) has been investigated. Ultraviolet (UV) absorption spectra, atomic force microscopy (AFM), high performance liquid chromatography (HPLC) and gas chromatogram-mass spectrum (GC/MS) are used to monitor the degradation process and to identify the major oxidation intermediate products. It has been found that 2,4-DCP undergoes a series of intermediate step, which leads to form a number of intermediate products, mainly isomeric chlorophenols and aliphatic acids. These products are further oxidized, eventually, mineralized into CO{sub 2} and Cl{sup -}. A degradation pathway for 2,4-DCP is proposed on the basis of detection of intermediate compounds.

  8. Tritium isotope separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    A process for separating tritium from light and heavy water is described. Hydrogen is transferred at and through bipolar electrodes at rates H > D > T. In a cell containing several bipolar electrodes placed in series between two terminal electrodes, a flow of hydrogen is established from the terminal anode compartment toward the terminal cathode. An electrolyte feed containing tritium is continuously added to the system and is subsequently transported countercurrent to the hydrogen mass transfer. A cascaded system is established, in which effluent streams enriched and depleted in tritium can be withdrawn. The voltage drop is smaller at any bipolar electrode as compared to the voltage for normal electrolysis. Cell design is compact because isotope separation occurs at bipolar electrodes without evolution of gas. Isotope separation was demonstrated in laboratory cells where a steady-state tritium concentration gradient was attained. This gradient was in agreement with concentrations calculated from a derived mathematical model

  9. Electrolysis of plutonium nitride in LiCl-KCl eutectic melts

    Science.gov (United States)

    Shirai, O.; Iwai, T.; Shiozawa, K.; Suzuki, Y.; Sakamura, Y.; Inoue, T.

    2000-01-01

    The electrolysis of plutonium nitride, PuN, was investigated in the LiCl-KCl eutectic salt with 0.54 wt% PuCl 3 at 773 K in order to understand the dissolution of PuN at the anode and the deposition of metal at the cathode from the viewpoint of the application of a pyrochemical process to nitride fuel cycle. It was found from cyclic voltammetry that the electrochemical dissolution of PuN began nearly at the theoretically evaluated potential and this reaction was irreversible. Several grams of plutonium metal were successfully recovered at the molybdenum electrode as a deposit with a current efficiency of about 90%, although some fractions of the deposited plutonium often fell from the molybdenum electrode.

  10. Electrolysis of plutonium nitride in LiCl-KCl eutectic melts

    International Nuclear Information System (INIS)

    The electrolysis of plutonium nitride, PuN, was investigated in the LiCl-KCl eutectic salt with 0.54 wt% PuCl3 at 773 K in order to understand the dissolution of PuN at the anode and the deposition of metal at the cathode from the viewpoint of the application of a pyrochemical process to nitride fuel cycle. It was found from cyclic voltammetry that the electrochemical dissolution of PuN began nearly at the theoretically evaluated potential and this reaction was irreversible. Several grams of plutonium metal were successfully recovered at the molybdenum electrode as a deposit with a current efficiency of about 90%, although some fractions of the deposited plutonium often fell from the molybdenum electrode

  11. The Role of Fe(II) in the Contact Glow Discharge Electrolysis

    International Nuclear Information System (INIS)

    In this paper, we use methyl violet as a model organic substrate in wastewater to study the effect of Fe(II) ion on the contact glow discharge electrolysis (CGDE). The decoloration rate and the COD (Chemical Oxygen Demand) value have been examined. It is found that the presence of Fe(II) ion can accelerate obviously the degradation of methyl violet, because it reacts with H2O2 in the CGDE process to yield hydroxyl radical, just acting as a Fenton-like reagent. Moreover, the optimal conditions for decoloring methyl violet were obtained, by means of an orthogonal experiment, to be [Fe2+] =1x 10-3 mol/L, applied voltage of 700 V of and pH = 9.0

  12. Iron migration from the anode surface in alumina electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, Elena N.; Drozdova, Tatiana N.; Ponomareva, Svetlana V. [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Kirik, Sergei D., E-mail: kiriksd@yandex.ru [Siberian Federal University, Krasnoyarsk, 660041 (Russian Federation); Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, 660036 (Russian Federation)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. Black-Right-Pointing-Pointer It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe{sup 2+} takes place. Black-Right-Pointing-Pointer Fe{sup 2+} interacts with cryolite melt producing FeF{sub 2}. Black-Right-Pointing-Pointer FeF{sub 2} gives oxides FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Black-Right-Pointing-Pointer The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF{sub 3} electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF{sub 2}. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl{sub 2}O{sub 4}, Fe{sub 3}O{sub 4}, Fe{sub 2}O{sub 3}. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The

  13. Experimental study of the electrolysis of silicate melts

    Science.gov (United States)

    Keller, R.; Larimer, K. T.

    1991-01-01

    To produce oxygen from lunar resources, it may be feasible to melt and electrolyze local silicate ores. This possibility was explored experimentally with synthesized melts of appropriate compositions. Platinum electrodes were employed at a melt temperature of 1425 C. When silicon components of the melt were reduced, the platinum cathode degraded rapidly, which prompted the substitution of a graphite cathode substrate. Discrete particles containing iron or titanium were found in the solidified electrolyte after three hours of electrolysis. Electrolyte conductivities did not decrease substantially, but the escape of gas bubbles, in some cases, appeared to be hindered by high viscosity of the melt.

  14. DEGRADATION ISSUES IN SOLID OXIDE CELLS DURING HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots; V. I. Sharma; B. Yildiz; A. V. Virkar

    2010-06-01

    Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problems between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL’s test results on high temperature electrolysis (HTE) using solid oxide cells do not provide a clear evidence whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become non-conductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. University of Utah (Virkar) has developed a SOEC model based on concepts in local thermodynamic equilibrium in

  15. Thermal imaging of solid oxide cells operating under electrolysis conditions

    Science.gov (United States)

    Cumming, D. J.; Elder, R. H.

    2015-04-01

    Solid oxide fuel cells remain at the forefront of research into electrochemical energy conversion technology. More recent interest has focused on operating in electrolyser mode to convert steam or carbon dioxide into hydrogen or carbon monoxide, respectively. The mechanism of these reactions is not fully understood, particularly when operated in co-electrolysis mode using both steam and CO2. This contribution reports the use of a thermal camera to directly observe changes in the cell temperature during operation, providing a remote, non-contact and highly sensitive method for monitoring an operational cell.

  16. Iron migration from the anode surface in alumina electrolysis

    International Nuclear Information System (INIS)

    Highlights: ► Corrosion destruction of two-component iron-based alloys in high-temperature aluminum electrolysis in the cryolite alumina melt has been studied. ► It was found that at the first stage oxidative polarization of iron atoms on the anode surface into Fe2+ takes place. ► Fe2+ interacts with cryolite melt producing FeF2. ► FeF2 gives oxides FeAl2O4, Fe3O4, Fe2O3. ► The participation of oxygen in the corrosion has not been observed. - Abstract: Corrosion destruction of two-component iron-based alloys used as an anode in high-temperature alumina electrolysis in the melt of NaF/KF/AlF3 electrolyte has been considered. Ni, Si, Cu, Cr, Mn, Al, Ti in the amount of up to 10% have been tested as the dopants to an anode alloys. The composition of the corrosion products has been studied using X-ray diffraction, scanning electron microscopy and electron microprobe analysis. It has been established that the anode corrosion is induced by a surface electrochemical polarization and iron atom oxidation. Iron ions come into an exchange interaction with the fluoride components of the melted electrolyte, producing FeF2. The last interacts with oxyfluoride species transforming into the oxide forms: FeAl2O4, Fe3O4, Fe2O3. Due to the low solubility, the iron oxides are accumulated in the near-electrode sheath. The only small part of iron from anode migrates to cathode that makes an production of high purity aluminum of a real task. The alloy dopants are also subjected to corrosion in accordance with electromotive series resulting corrosion tunnels on the anode surface. The oxides are final compounds which collect in the same area. The corrosion products form an anode shell which is electronic conductor at electrolysis temperature. The electrolysis of alumina occurs beyond the corrosion shell. The rate limiting step in the corrosion is the electrolyte penetration through corrosion shell to the anode surface. The participation of the released oxygen in the corrosion has

  17. Magnetohydrodynamics simulation of 300 KA novel cell for aluminum electrolysis

    Directory of Open Access Journals (Sweden)

    Y. Song

    2015-10-01

    Full Text Available A novel cathode with cylindrical protrusions was presented to investigate the effect of protrusions on the electromagnetic field and flow field in the aluminum electrolysis cell. Results show that by using the novel cathode, the maximum horizontal electromagnetic force and velocity at 2/3 height of the metal pad were reduced by 21 % and 41 % respectively, and the metal - bath interface wave decreased by 0,69 cm. The metal pad flows around protrusions. Eddies due to boundary layer separation are beneficial to the dissolution of alumina.

  18. Considerations on electrolysis in electromembrane extraction of basic drugs

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Kubáň, Pavel; Boček, Petr

    Brno: Ústav analytické chemie AV ČR, v. v. i, 2015 - (Foret, F.; Křenková, J.; Drobníková, I.; Klepárník, K.), s. 198-201 ISBN 978-80-904959-3-7. [CECE 2015. International Interdisciplinary Meeting on Bioanalysis /12./. Brno (CZ), 21.09.2015-23.09.2015] R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : electrolysis * electromembrane extraction * basic drugs Subject RIV: CB - Analytical Chemistry, Separation http://www.ce-ce.org/CECE2015/CECE%202015%20proceedings_full.pdf

  19. Developments in alkali-metal atomic magnetometry

    Science.gov (United States)

    Seltzer, Scott Jeffrey

    Alkali-metal magnetometers use the coherent precession of polarized atomic spins to detect and measure magnetic fields. Recent advances have enabled magnetometers to become competitive with SQUIDs as the most sensitive magnetic field detectors, and they now find use in a variety of areas ranging from medicine and NMR to explosives detection and fundamental physics research. In this thesis we discuss several developments in alkali-metal atomic magnetometry for both practical and fundamental applications. We present a new method of polarizing the alkali atoms by modulating the optical pumping rate at both the linear and quadratic Zeeman resonance frequencies. We demonstrate experimentally that this method enhances the sensitivity of a potassium magnetometer operating in the Earth's field by a factor of 4, and we calculate that it can reduce the orientation-dependent heading error to less than 0.1 nT. We discuss a radio-frequency magnetometer for detection of oscillating magnetic fields with sensitivity better than 0.2 fT/ Hz , which we apply to the observation of nuclear magnetic resonance (NMR) signals from polarized water, as well as nuclear quadrupole resonance (NQR) signals from ammonium nitrate. We demonstrate that a spin-exchange relaxation-free (SERF) magnetometer can measure all three vector components of the magnetic field in an unshielded environment with comparable sensitivity to other devices. We find that octadecyltrichlorosilane (OTS) acts as an anti-relaxation coating for alkali atoms at temperatures below 170°C, allowing them to collide with a glass surface up to 2,000 times before depolarizing, and we present the first demonstration of high-temperature magnetometry with a coated cell. We also describe a reusable alkali vapor cell intended for the study of interactions between alkali atoms and surface coatings. Finally, we explore the use of a cesium-xenon SERF comagnetometer for a proposed measurement of the permanent electric dipole moments (EDMs

  20. Method and system for purification of gas/liquid streams for fuel cells or electrolysis cells

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention provides in embodiments a method for purification of inlet gas/liquid streams in a fuel cell or electrolysis cell, the fuel cell or electrolysis cell comprising at least a first electrode, an electrolyte and a second electrode, the method comprising the steps of: - providing...... at least one scrubber in the gas/liquid stream at the inlet side of the first electrode of the fuel cell or electrolysis cell; and/or providing at least one scrubber in the gas/liquid stream at the inlet side of the second electrode of the fuel cell or electrolysis cell; and - purifying the gas...... purified with the at least one scrubber, with the proviso that the fuel cell or electrolysis cell is not a solid oxide cell....

  1. Perovskites As Electrocatalysts for Alkaline Water Electrolysis

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; De La Osa Puebla, Ana Raquel; Jensen, Jens Oluf;

    2014-01-01

    robust method for synthesis of perovskites with various chemical compositions1. The electrochemical performance of the materials was tested through pellet pressing of the perovskite powders. This involved in some case a time consuming preparation process. Furthermore the technique should show the...... adequate reproducibility.2 In this work we show the development of the method, which was further used to compare the activity of various electrocatalysts (Figures 1,2). The electrocatalytic activity of all prepared perovskites was tested in 1M KOH at 80 °C, using an ink consisting of potassium exchanged...... Nafion®. All tests were performed in the potential window 0-700 mV on a glassy carbon electrode. All the tested perovskites were characterized by their overpotential , measured current at 650 mV, obtained kinetic current and Tafel slopes. It was also shown that this technique do not depend on the initial...

  2. Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

    Directory of Open Access Journals (Sweden)

    Yomei Tokuda

    2015-12-01

    Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

  3. Saturated vapor pressure above the amalgam of alkali metals in discharge lamps

    Science.gov (United States)

    Gavrish, S. V.

    2011-12-01

    A theoretical and numerical analysis of the evaporation process of two-component compounds in vapors of alkali metals in discharge lamps is presented. Based on the developed mathematical model of calculation of saturated vapor pressure of the metal above the amalgam, dependences of mass fractions of the components in the discharge volume on design parameters and thermophysical characteristics of the lamp are obtained.

  4. On the origin of the mixed alkali effect on indentation in silicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Mauro, J. C.; Yue, Yuanzheng

    2014-01-01

    deformation processes (elastic deformation, plastic deformation, and densification) and Hv in two mixed sodium–potassium silicate glass series. We show that the mixed alkali effect in Hv originates from the nonlinear scaling of the resistance to plastic deformation. We thus confirm a direct relation between...

  5. Effect of alkali lignins with different molecular weights from alkali pretreated rice straw hydrolyzate on enzymatic hydrolysis.

    Science.gov (United States)

    Li, Yun; Qi, Benkun; Luo, Jianquan; Wan, Yinhua

    2016-01-01

    This study investigated the effect of alkali lignins with different molecular weights on enzymatic hydrolysis of lignocellulose. Different alkali lignins fractions, which were obtained from cascade ultrafiltration, were added into the dilute acid pretreated (DAP) and alkali pretreated (AP) rice straws respectively during enzymatic hydrolysis. The results showed that the addition of alkali lignins enhanced the hydrolysis and the enhancement for hydrolysis increased with increasing molecular weights of alkali lignins, with maximum enhancement being 28.69% for DAP and 20.05% for AP, respectively. The enhancement was partly attributed to the improved cellulase activity, and filter paper activity increased by 18.03% when adding lignin with highest molecular weight. It was found that the enhancement of enzymatic hydrolysis was correlated with the adsorption affinity of cellulase on alkali lignins, and the difference in surface charge and hydrophobicity of alkali lignins were responsible for the difference in affinity between cellulase and lignins. PMID:26496216

  6. Integration of Microbial Electrolysis Cells (MECs) in the Biorefinery for Production of Ethanol, H2 and Phenolics

    DEFF Research Database (Denmark)

    Thygesen, Anders; Thomsen, Anne Belinda; Possemiers, Sam;

    2010-01-01

    procedure is proposed in which the ethanol biorefinery is coupled with a microbial electrolysis cell (MEC), with the aim to further process and valorize the waste stream of bioethanol production. A MEC is an electrochemical system capable of oxidizing reducing equivalents, which results in hydrogen...... at 177–190 kg, with a hydrogen yield corresponding to 19–23 kg H2. The remaining solid residue of 147–160 kg comprises primarily lignin. The estimated value of these products approximates the double of that of straw. Integrating a MEC in the biorefinery concept may also be useful for other applications...

  7. Improving the adsorption ability of graphene sheets to uranium through chemical oxidation, electrolysis and ball-milling

    International Nuclear Information System (INIS)

    Three types of graphene sheets (GS) were decorated by chemical oxidation, electrolysis and ball-milling, respectively. These oxidized samples were characterized using SEM, XRD, Raman, FT-IR and XPS, and then were employed to enrich U(VI) from aqueous solutions as a function of pH, contact time and initial concentration of U(VI). These results displayed that the quantities and types of oxygen-functional groups were extremely different through these methods, which highly determined the adsorption capacity of graphene oxide to uranium. This work may provide some helpful information to optimize these fabrication processes and improve the adsorption ability of GS to uranium. (author)

  8. Electrochemical extraction of oxygen using PEM electrolysis technology

    Directory of Open Access Journals (Sweden)

    BOULBABA ELADEB

    2012-11-01

    Full Text Available Electrochemical extraction of oxygen from air can be carried out by chemical reduction of oxygen at the cathode and simultaneous oxygen evolution by water anode oxidation. The present investigation deals with the use of an electrolysis cell of PEM technology for this purpose. A dedicated 25 cm2 cell provided with a commercial water electrolysis MEA and titanium grooved plates has been designed for continuous operation at pressures close to the ambient level. The MEA consisted of a Nafion 117 membrane sandwiched between a Pt/C cathode and a non-supported Pt-Ir anode. Oxygen partial consumption in long-term runs was evaluated by analysis of the outlet air by gas chromatography, depending on the cell voltage - or the current density - and the excess in air oxygen fed to the cathode. Runs over more 50 hours indicated the relative stability of the components used for current densities ranging from 0.1 to 0.2 A cm-2 with high efficiency of oxygen reduction. Higher current density could be envisaged with more efficient MEA’s, exhibiting lower overpotentials for oxygen evolution to avoid too significant degradation of the anode material and the membrane. Interpretation of the data has been carried out by calculation of the cathode current efficiency.

  9. Water electrolysis in the presence of an ultrasonic field

    International Nuclear Information System (INIS)

    The energy efficiency of water electrolysis has been considerably improved in the presence of an ultrasonic field. This was demonstrated by measuring the cell voltage, efficiency and energy consumption of the generated gas from the electrolysis. These measurements were carried out in alkaline solution using linear sweep voltammetry (LSV) and galvanostatic polarization techniques. A large reduction of the cell voltage was achieved under the ultrasonic field, especially at high current density and low electrolyte concentration. With the same current density, the cell voltage difference with and without the ultrasonic field fell as the concentration of the electrolyte was increased. The efficiency of H2 generation was improved at a range of 5-18% at high current density in the ultrasonic field but the efficiency of O2 generation fell a little due to the difference in the behavior of the gas bubbles. The energy saving for H2 production by using the ultrasonic field was about 10-25% for a certain concentration of the electrolyte when a high current density was used. On the other hand, the energy consumption for O2 production with and without the ultrasonic field was almost the same.

  10. Cathode for tritium-forming exothermic reaction by electrolysis

    International Nuclear Information System (INIS)

    The present invention provides a cathode used for a reaction in which liquid containing heavy water is electrolyzed under a room temperature to generate energy greater than that required for electrolysis in the liquid. The cathode used in this electrolysis includes any of those described below. (a) metal uranium (U metal) coated with palladium (Pd), (b) U metal contained in porous aluminum (Al203) container and (c) an alloy of U metal and Pd metal contained in a porous aluminum container. According to the result of an experiment, the temperature of the electrolyte is elevated to 40degC at 50 min after the start of electric supply and tritium in the electrolyte is increased to about three times of background, by using any one of cathodes (a), (b) and (c). Based on the result of the experiment, it is assumed that a specific tritium-forming exothermic reaction like that a nuclear fusion reaction is caused in this reaction. (I.S.)

  11. Interactions of alkali metals and electrolyte with cathode carbons

    Energy Technology Data Exchange (ETDEWEB)

    Naas, Tyke

    1997-12-31

    The Hall-Heroult process for electrolytic reduction of alumina has been the only commercial process for production of primary aluminium. The process runs at high temperature and it is important to minimize the energy consumption. To save energy it is desirable to reduce the operating temperature. This can be achieved by adding suitable additives such as LiF or KF to the cryolitic electrolyte. This may conflict with the objective of extending the lifetime of the cathode linings of the cell as much as possible. The thesis investigates this possibility and the nature of the interactions involved. It supports the hypothesis that LiF-additions to the Hall-Heroult cell electrolyte is beneficial to the carbon cathode performance because the diminished sodium activity reduces the sodium induced stresses during the initial period of electrolysis. The use of KF as an additive is more dangerous, but the results indicate that additions up to 5% KF may be tolerated in acidic melts with semigraphitic or graphitic cathodes with little risk of cathode problems. 153 refs., 94 figs., 30 tabs.

  12. Transport properties of alkali metal doped fullerides

    International Nuclear Information System (INIS)

    We have studied the intercage interactions between the adjacent C60 cages and expansion of lattice due to the intercalation of alkali atoms based on the spring model to estimate phonon frequencies from the dynamical matrix for the intermolecular alkali-C60 phonons. We considered a two-peak model for the phonon density of states to investigate the nature of electron pairing mechanism for superconducting state in fullerides. Coulomb repulsive parameter and the electron phonon coupling strength are obtained within the random phase approximation. Transition temperature, Tc, is obtained in a situation when the free electrons in lowest molecular orbital are coupled with alkali-C60 phonons as 5 K, which is much lower as compared to reported Tc (20 K). The superconducting pairing is mainly driven by the high frequency intramolecular phonons and their effects enhance it to 22 K. The importance of the present study, the pressure effect and normal state transport properties are calculated within the same model leading superconductivity

  13. Transport properties of alkali metal doped fullerides

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Daluram, E-mail: daluramyadav@gmail.com; Yadav, Nishchhal, E-mail: somyadav@gmail.com [School of studies in Physics, Vikram University, Ujjain (M.P) India (India)

    2015-07-31

    We have studied the intercage interactions between the adjacent C{sub 60} cages and expansion of lattice due to the intercalation of alkali atoms based on the spring model to estimate phonon frequencies from the dynamical matrix for the intermolecular alkali-C{sub 60} phonons. We considered a two-peak model for the phonon density of states to investigate the nature of electron pairing mechanism for superconducting state in fullerides. Coulomb repulsive parameter and the electron phonon coupling strength are obtained within the random phase approximation. Transition temperature, T{sub c}, is obtained in a situation when the free electrons in lowest molecular orbital are coupled with alkali-C{sub 60} phonons as 5 K, which is much lower as compared to reported T{sub c} (20 K). The superconducting pairing is mainly driven by the high frequency intramolecular phonons and their effects enhance it to 22 K. The importance of the present study, the pressure effect and normal state transport properties are calculated within the same model leading superconductivity.

  14. Biological neutralization of chlor-alkali industry wastewater.

    Science.gov (United States)

    Jain, Rakeshkumar M; Mody, Kalpana H; Keshri, Jitendra; Jha, Bhavanath

    2011-11-01

    The present work reports biological neutralization of chlor-alkali industrial effluent by an alkaliphilic bacterium, isolated from the Gujarat coast, which was identified as Enterococcus faecium strain R-5 on the basis of morphological, biochemical and partial 16S rRNA gene sequencing. The isolate was capable of bringing down the pH of waste water from 12.0 to 7.0 within 3 h in the presence of carbon and nitrogen sources, with simultaneous reduction in total dissolved solutes (TDS) up to 19-22%. This bacterium produced carboxylic acid, as revealed by FT-IR analysis, which facilitated neutralization of alkaline effluent. The presence of unconventional raw materials viz. Madhuca indica flowers or sugar cane bagasse as carbon and nitrogen sources could effectively neutralize alkaline effluent and thus making the bioremediation process economically viable. The time required for neutralization varied with size of inoculum. To the best of our knowledge, this is the first report on biological neutralization of a chlor-alkali industrial effluent. PMID:21944194

  15. Effect of Mineral Admixtures on Alkali-Silica Reaction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chengzhi; WANG Aiqin

    2008-01-01

    The influence of silica fume,slag and fly ash on alkali-silica reaction under the condition of 70℃ is studied.The results show that silica,slag and fly ash may inhibit alkali-silica reaction only under suitable content.When the content is less than 10%,silica fume does not markedly influence the expansion of alkali-silica reaction.When the content is 15%-20%,silica fume only may delay the expansion of alkali-silica reaction.When the content is 30%-70%,slag may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is 10%,fly ash does not markedly influence the expansion of alkali-silica reaction.When the content is 20%-30%,fly ash may only delay the expansion of alkali-silica reaction,but cannot inhibit the expansion of alkali-silica reaction.When the content is over 50%,it is possible that fly ash can inhibit effectively alkali-silica reaction.

  16. A polarized alkali ion source

    International Nuclear Information System (INIS)

    The beam foil technique has been applied to detect nuclear vector polarization of a 10 keV 23Na+ beam. The result was about 70% of the atomic beam polarization thus limiting the depolarization by the surface ionizer to at most 30%. In a Coulomb excitation experiment with a tensor polarized 42 MeV 23Na7+ beam an effect of 0.011 +- 0.003 was measured yielding a value of t20 approx. 0.04 for the beam polarization. The depolarization during the acceleration process can be estimated to be about 0.8. (orig.)

  17. A GIS-based Tupu Analysis of Dynamics of Saline-alkali Land in Western Jilin Province

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on Tupu theory, this paper studied the.dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the western Jilin Province in 1980-2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da'an during 1995-2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography,predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da'an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da'an fluctuated greatly.The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development.

  18. High-pressure water electrolysis: Electrochemical mitigation of product gas crossover

    International Nuclear Information System (INIS)

    Highlights: • New technique to reduce gas crossover during water electrolysis • Increase of the efficiency of pressurized water electrolysis • Prevention of safety hazards due to explosive gas mixtures caused by crossover • Experimental realization for a polymer electrolyte membrane electrolyzer • Discussion of electrochemical crossover mitigation for alkaline water electrolysis - Abstract: Hydrogen produced by water electrolysis can be used as an energy carrier storing electricity generated from renewables. During water electrolysis hydrogen can be evolved under pressure at isothermal conditions, enabling highly efficient compression. However, the permeation of hydrogen through the electrolyte increases with operating pressure and leads to efficiency loss and safety hazards. In this study, we report on an innovative concept, where the hydrogen crossover is electrochemically mitigated by an additional electrode between the anode and the cathode of the electrolysis cell. Experimentally, the technique was applied to a proton exchange membrane water electrolyzer operated at a hydrogen pressure that was fifty times larger than the oxygen pressure. Therewith, the hydrogen crossover was reduced and the current efficiency during partial load operation was increased. The concept is also discussed for water electrolysis that is operated at balanced pressures, where the crossover of hydrogen and oxygen is mitigated using two additional electrodes

  19. Experimental Demonstration of the Molten Oxide Electrolysis Method for Oxygen and Iron Production from Simulated Lunar Materials

    Science.gov (United States)

    Curreri, P. A.; Ethridge, E.; Hudson, S.; Sen, S.

    2006-01-01

    This paper presents the results of a Marshall Space Flight Center funded effort to conduct an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis (MOE) process to produce oxygen and metal from lunar resources to support human exploration of space. Oxygen extracted from lunar materials can be used for life support and propellant, and silicon and metallic elements produced can be used for in situ fabrication of thin-film solar cells for power production. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis, MOE, is chosen for extraction, since the electron is the most practical reducing agent. MOE was also chosen for following reasons. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. In the experiments reported here, melts containing iron oxide were electrolyzed in a low temperature supporting oxide electrolyte (developed by D. Sadoway, MIT).

  20. Oxygen Handling and Cooling Options in High Temperature Electrolysis Plants

    Energy Technology Data Exchange (ETDEWEB)

    Manohar S. Sohal; J. Stephen Herring

    2008-07-01

    Idaho National Laboratory is working on a project to generate hydrogen by high temperature electrolysis (HTE). In such an HTE system, safety precautions need to be taken to handle high temperature oxygen at ~830°C. This report is aimed at addressing oxygen handling in a HTE plant.. Though oxygen itself is not flammable, most engineering material, including many gases and liquids, will burn in the presence of oxygen under some favorable physicochemical conditions. At present, an absolute set of rules does not exist that can cover all aspects of oxygen system design, material selection, and operating practices to avoid subtle hazards related to oxygen. Because most materials, including metals, will burn in an oxygen-enriched environment, hazards are always present when using oxygen. Most materials will ignite in an oxygen-enriched environment at a temperature lower than that in air, and once ignited, combustion rates are greater in the oxygen-enriched environment. Even many metals, if ignited, burn violently in an oxygen-enriched environment. However, these hazards do not preclude the operations and systems involving oxygen. Oxygen can be safely handled and used if all the materials in a system are not flammable in the end-use environment or if ignition sources are identified and controlled. In fact, the incidence of oxygen system fires is reported to be low with a probability of about one in a million. This report is a practical guideline and tutorial for the safe operation and handling of gaseous oxygen in high temperature electrolysis system. The intent is to provide safe, practical guidance that permits the accomplishment of experimental operations at INL, while being restrictive enough to prevent personnel endangerment and to provide reasonable facility protection. Adequate guidelines are provided to govern various aspects of oxygen handling associated with high temperature electrolysis system to generate hydrogen. The intent here is to present acceptable

  1. CONTRIBUTION TO THE STUDY OF HYDROXYMETYLATION REACTION OF ALKALI LIGNIN

    OpenAIRE

    Teodor Malutan; Raluca Nicu; Valentin I. Popa

    2008-01-01

    The hydroxymethylation of alkali lignin with formaldehyde in alkaline solution was studied. The influence of reaction conditions of the hydroxymethylation of alkali lignin was followed by modifying the temperature, time, and the ratios of NaOH to lignin and CH2O to lignin. Three different types of alkali lignin were utilized. The reaction was followed by total consumption of formaldehyde, and the resulting products were characterized through FTIR-spectra, thermogravimetry analysis, ash and mo...

  2. Demonstration and System Analysis of High Temperature Steam Electrolysis for Large-Scale Hydrogen Production Using SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Michael G. McKellar; James E. O' Brien; Carl M. Stoots; J. Stephen Herring

    2008-07-01

    At the Idaho National Engineering Laboratory, an integrated laboratory scale (ILS), 15 kW high-temperature electrolysis (HTE) facility has been developed under the U.S. Department of Energy Nuclear Hydrogen Initiative. Initial operation of this facility resulted in over 400 hours of operation with an average hydrogen production rate of approximately 0.9 Nm3/hr. The integrated laboratory scale facility is designed to address larger-scale issues such as thermal management (feed-stock heating, high-temperature gas handling), multiple-stack hot-zone design, multiple-stack electrical configurations, and other “integral” issues. Additionally, a reference process model of a commercial-scale high-temperature electrolysis plant for hydrogen production has been developed. The reference plant design is driven by a 600 megawatt thermal high-temperature helium-cooled reactor coupled to a direct Brayton power cycle. The electrolysis unit used to produce hydrogen consists of 4.01×106 cells with a per-cell active area of 225 cm2. A nominal cell area-specific resistance, ASR, value of 0.4 Ohm•cm2 with a current density of 0.25 A/cm2 was used, and isothermal boundary conditions were assumed. The overall system thermal-to-hydrogen production efficiency (based on the low heating value of the produced hydrogen) is 47.1% at a hydrogen production rate of 2.36 kg/s with the high-temperature helium-cooled reactor concept. This paper documents the initial operation of the ILS, with experimental details about heat-up, initial stack performance, as well as long-term operation and stack degradation. The paper will also present the optimized design for the reference nuclear-driven HTE hydrogen production plant which may be compared with other hydrogen production methods and power cycles to evaluate relative performance characteristics and plant economics.

  3. Development of a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) cell for the in situ analysis of co-electrolysis in a solid oxide cell.

    Science.gov (United States)

    Cumming, Denis J; Tumilson, Christopher; Taylor, S F Rebecca; Chansai, Sarayute; Call, Ann V; Jacquemin, Johan; Hardacre, Christopher; Elder, Rachael H

    2015-01-01

    Co-electrolysis of carbon dioxide and steam has been shown to be an efficient way to produce syngas, however further optimisation requires detailed understanding of the complex reactions, transport processes and degradation mechanisms occurring in the solid oxide cell (SOC) during operation. Whilst electrochemical measurements are currently conducted in situ, many analytical techniques can only be used ex situ and may even be destructive to the cell (e.g. SEM imaging of the microstructure). In order to fully understand and characterise co-electrolysis, in situ monitoring of the reactants, products and SOC is necessary. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) is ideal for in situ monitoring of co-electrolysis as both gaseous and adsorbed CO and CO2 species can be detected, however it has previously not been used for this purpose. The challenges of designing an experimental rig which allows optical access alongside electrochemical measurements at high temperature and operates in a dual atmosphere are discussed. The rig developed has thus far been used for symmetric cell testing at temperatures from 450 °C to 600 °C. Under a CO atmosphere, significant changes in spectra were observed even over a simple Au|10Sc1CeSZ|Au SOC. The changes relate to a combination of CO oxidation, the water gas shift reaction, carbonate formation and decomposition processes, with the dominant process being both potential and temperature dependent. PMID:26212555

  4. High Temperature Electrolysis 4 kW Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; K. DeWall; L. Moore-McAteer; G. Tao

    2012-09-01

    This report provides results of long-term stack testing completed in the new high-temperature steam electrolysis multi-kW test facility recently developed at INL. The report includes detailed descriptions of the piping layout, steam generation and delivery system, test fixture, heat recuperation system, hot zone, instrumentation, and operating conditions. This facility has provided a demonstration of high-temperature steam electrolysis operation at the 4 kW scale with advanced cell and stack technology. This successful large-scale demonstration of high-temperature steam electrolysis will help to advance the technology toward near-term commercialization.

  5. Coprecipitation of alkali metal ions with calcium carbonate

    International Nuclear Information System (INIS)

    The coprecipitation of alkali metal ions Li+, Na+, K+ and Rb+ with calcium carbonate has been studied experimentally and the following results have been obtained: (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite and their ionic radii shows a parabolic curve with a peak located at Na+ which has approximately the same ionic radius as Ca2+. (3) However, the amounts of alkali metal ions coprecipitated with calcite decrease with increasing ionic radius of alkali metals. (4) Our results support the hypothesis that (a) alkali metals are in interstitial positions in the crystal structure of calcite and do not substitute for Ca2+ in the lattice, but (b) in aragonite, alkali metals substitute for Ca2+ in the crystal structure. (5) Magnesium ions in the parent solution increase the amounts of alkali metal ions (Li+, Na+, K+ and Rb+) coprecipitated with calcite but decrease those with aragonite. (6) Sodium-bearing aragonite decreases the incorporation of other alkali metal ions (Li+, K+ and Rb+) into the aragonite. (author)

  6. HYFIRE: a tokamak- high-temperature electrolysis system

    International Nuclear Information System (INIS)

    Brookhaven National Laboratory is involved in a conceptual design study of a commercial nuclear power system which utilizes high-temperature electrolysis to produce synthetic fuels. The system is called HYFIRE. It includes a tokamak fusion power reactor supplying electrical and thermal energy to an array of electrolytes. The electrolytes produce hydrogen which can be used either directly as a fuel or in the production of hydrocarbons. The purpose of the study is to provide a mechanism for DOE to further assess the commercial potential of fusion using a tokamak reactor to produce synthetic fuel. The HYFIRE design is based on the tokamak commercial power reactor, STARFIRE. STARFIRE uses the deuterium/tritium/lithium fuel cycle. The HYFIRE study assumes the plasma shape and characteristics of STARFIRE study but uses a different blanket design. This study is particularly interested in the possibility of using the STARFIRE tokamak in the production of synthetic fuels

  7. Measurement of neutrons in electrolysis at low temperature range

    International Nuclear Information System (INIS)

    We observed three neutron trains continuing 2 or 3h as the excess flux during an electrolysis of deuterated alcoholic electrolyte at low temperature range with Pd cathode for 1878h. Those were 22 counts/2h and two times of 27 counts/3h in the average background counts of 4/h. We could not find any excess in the other time intervals between 28.6ms and 1878h. The production rates of the 22 and 27 counts were 6.3x10-24 and 4.5x10-24/d-d/s during 2 and 3h, respectively. The confidence levels of neutron emission for 22/2h and 27/3h were 88% and 59%, respectively, estimated from the statistics. And for the total of the three trains, the confidence level became 98%. (author)

  8. Advancements in water vapor electrolysis technology. [for Space Station ECLSS

    Science.gov (United States)

    Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin

    1988-01-01

    The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

  9. Water quality improvement of a lagoon containing mixed chemical industrial wastewater by micro-electrolysis-contact oxidization

    Institute of Scientific and Technical Information of China (English)

    Ya-fei ZHOU; Mao LIU; Qiong WU

    2011-01-01

    A lagoon in the New Binhai District, a high-speed developing area, Tianjin, China, has long been receiving the mixed chemical industrial wastewater from a chemical industrial park. This lagoon contained complex hazardous substances such as heavy metals and accumulative pollutants which stayed over time with a poor biodegradability. According to the characteristics of wastewater in the lagoon, the micro-electrolysis process was applied to improve the biodegradability before the bioprocess treatment. By the orthogonal experimental study of main factors influencing the efficiency of the treatment method, the best control parameters were obtained, including pH=2.0, a volume ratio of Fe and reaction wastewater of 0.03750, a volume ratio of Fe and the granular activated carbon (GAC) of 2.0, a mixing speed of 200 r/min, and a hydraulic retention time (HRT) of 1.5 h. In the meantime, the removal rate of chemical oxygen demand (COD) was up to 64.6%, and NH4-N and Pb in the influent were partly removed. After the micro-electrolysis process, the ratio of biochemical oxygen demand (BOD) to COD (B/C ratio) was greater than 0.6, thus providing a favorable basis for bioprocess treatment.

  10. Cathode architectures for alkali metal / oxygen batteries

    Energy Technology Data Exchange (ETDEWEB)

    Visco, Steven J; Nimon, Vitaliy; De Jonghe, Lutgard C; Volfkovich, Yury; Bograchev, Daniil

    2015-01-13

    Electrochemical energy storage devices, such as alkali metal-oxygen battery cells (e.g., non-aqueous lithium-air cells), have a cathode architecture with a porous structure and pore composition that is tailored to improve cell performance, especially as it pertains to one or more of the discharge/charge rate, cycle life, and delivered ampere-hour capacity. A porous cathode architecture having a pore volume that is derived from pores of varying radii wherein the pore size distribution is tailored as a function of the architecture thickness is one way to achieve one or more of the aforementioned cell performance improvements.

  11. Fundamental study of nanostructured electro-catalysts with reduced noble metal content for PEM based water electrolysis

    Science.gov (United States)

    Kadakia, Sandeep Karan

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO 2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO 2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O 2 thin films of different compositions have also been studied. It has been shown that (Ir0.40Sn0.30Nb 0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would potentially be preferred as OER electro-catalysts for PEM electrolysis. The excellent performance of the catalysts coupled with its robustness would make them great candidates for contributing to significant reduction in the overall capital costs of PEM based water electrolyzers. This thesis provides a detailed fundamental study of the synthesis, materials, characterization, theoretical studies and detailed electrochemical response and potential

  12. Elucidation of transport mechanism and enhanced alkali ion transference numbers in mixed alkali metal-organic ionic molten salts.

    Science.gov (United States)

    Chen, Fangfang; Forsyth, Maria

    2016-07-28

    Mixed salts of Ionic Liquids (ILs) and alkali metal salts, developed as electrolytes for lithium and sodium batteries, have shown a remarkable ability to facilitate high rate capability for lithium and sodium electrochemical cycling. It has been suggested that this may be due to a high alkali metal ion transference number at concentrations approaching 50 mol% Li(+) or Na(+), relative to lower concentrations. Computational investigations for two IL systems illustrate the formation of extended alkali-anion aggregates as the alkali metal ion concentration increases. This tends to favor the diffusion of alkali metal ions compared with other ionic species in electrolyte solutions; behavior that has recently been reported for Li(+) in a phosphonium ionic liquid, thus an increasing alkali transference number. The mechanism of alkali metal ion diffusion via this extended coordination environment present at high concentrations is explained and compared to the dynamics at lower concentrations. Heterogeneous alkali metal ion dynamics are also evident and, somewhat counter-intuitively, it appears that the faster ions are those that are generally found clustered with the anions. Furthermore these fast alkali metal ions appear to correlate with fastest ionic liquid solvent ions. PMID:27375042

  13. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    Energy Technology Data Exchange (ETDEWEB)

    None

    1991-12-01

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.

  14. Strong Turbulence in Alkali Halide Negative Ion Plasmas

    Science.gov (United States)

    Sheehan, Daniel

    1999-11-01

    Negative ion plasmas (NIPs) are charge-neutral plasmas in which the negative charge is dominated by negative ions rather than electrons. They are found in laser discharges, combustion products, semiconductor manufacturing processes, stellar atmospheres, pulsar magnetospheres, and the Earth's ionosphere, both naturally and man-made. They often display signatures of strong turbulence^1. Development of a novel, compact, unmagnetized alkali halide (MX) NIP source will be discussed, it incorporating a ohmically-heated incandescent (2500K) tantulum solenoid (3cm dia, 15 cm long) with heat shields. The solenoid ionizes the MX vapor and confines contaminant electrons, allowing a very dry (electron-free) source. Plasma densities of 10^10 cm-3 and positive to negative ion mass ratios of 1 Fusion 4, 91 (1978).

  15. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    International Nuclear Information System (INIS)

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references

  16. Syngas production on a symmetrical solid oxide H2O/CO2 co-electrolysis cell with Sr2Fe1.5Mo0.5O6-Sm0.2Ce0.8O1.9 electrodes

    Science.gov (United States)

    Wang, Yao; Liu, Tong; Fang, Shumin; Chen, Fanglin

    2016-02-01

    High temperature H2O/CO2 co-electrolysis process is performed on the symmetrical Sr2Fe1.5Mo0.5O6(SFM)-Sm0.2Ce0.8O1.9(SDC)/La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM)/SFM-SDC cells, which exhibit excellent electrochemical performance with the current density of -734 mAcm-2 at 1.3 V and the interfacial polarization resistance of 0.48 Ωcm2 at 850 °C. Enhanced co-electrolysis kinetics are obtained with increasing the operating temperature and applied cell voltage. Synthesis gas of H2 and CO is produced by H2O splitting and reverse water gas shift (RWGS) reaction on the SFM-SDC/LSGM/SFM-SDC co-electrolysis cells. Effects of temperature and electrolysis current on the produced gas fraction are predicted using the chemical equilibrium co-electrolysis model. High CO2 conversion rate and ideal H2 to CO ratio of approximately 2 can be achieved by adjusting appropriate inlet gas fraction, temperature and electrolysis current. The SFM-SDC/LSGM/SFM-SDC cell shows a relative stable cell voltage in the 103-h galvanostatic test.

  17. Alkali-Activated Aluminium-Silicate Composites as Insulation Materials for Industrial Application

    Science.gov (United States)

    Dembovska, L.; Bajare, D.; Pundiene, I.; Bumanis, G.

    2015-11-01

    The article reports on the study of thermal stability of alkali-activated aluminium- silicate composites (ASC) at temperature 800-1100°C. ASC were prepared by using calcined kaolinite clay, aluminium scrap recycling waste, lead-silicate glass waste and quartz sand. As alkali activator, commercial sodium silicate solution modified with an addition of sodium hydroxide was used. The obtained alkali activation solution had silica modulus Ms=1.67. Components of aluminium scrap recycling waste (aluminium nitride (AlN) and iron sulphite (FeSO3)) react in the alkali media and create gases - ammonia and sulphur dioxide, which provide the porous structure of the material [1]. Changes in the chemical composition of ASC during heating were identified and quantitatively analysed by using DTA/TG, dimension changes during the heating process were determined by using HTOM, pore microstructure was examined by SEM, and mineralogical composition of ASC was determined by XRD. The density of ASC was measured in accordance with EN 1097-7. ASC with density around 560 kg/m3 and heat resistance up to 1100°C with shrinkage less than 5% were obtained. The intended use of this material is the application as an insulation material for industrial purposes at elevated temperatures.

  18. Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

    KAUST Repository

    Zhu, Xiuping

    2013-06-01

    A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions representative of seawater and river water). A bipolar membrane (BPM) was placed next to the anode to prevent Cl- contamination and acidification of the anolyte, and to produce protons for HCl recovery. A 5-cell paired reverse-electrodialysis (RED) stack provided the electrical energy required to overcome the BPM over-potential (0.3-0.6 V), making the overall process spontaneous. The MRCC reactor produced electricity (908 mW/m2) as well as concentrated acidic and alkaline solutions, and therefore did not require an external power supply. After a fed-batch cycle, the pHs of the chemical product solutions were 1.65 ± 0.04 and 11.98 ± 0.10, due to the production of 1.35 ± 0.13 mmol of acid, and 0.59 ± 0.14 mmol of alkali. The acid- and alkali-production efficiencies based on generated current were 58 ± 3% and 25 ± 3%. These results demonstrated proof-of-concept acid and alkali production using only renewable energy sources. © 2013 Elsevier B.V.

  19. Mechanical and microstructural properties of alkali-activated fly ash geopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Komljenovic, M., E-mail: miroslav.komljenovic@imsi.rs [Institute for Multidisciplinary Research, Material Science, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bascarevic, Z., E-mail: zvezdana@cms.bg.ac.rs [Institute for Multidisciplinary Research, Material Science, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bradic, V., E-mail: violeta.bradic@cms.bg.ac.rs [Institute for Multidisciplinary Research, Material Science, Kneza Viseslava 1, 11030 Belgrade (Serbia)

    2010-09-15

    This paper investigates the properties of geopolymer obtained by alkali-activation of fly ash (FA), i.e. the influence of characteristics of the representative group of FA (class F) from Serbia, as well as that of the nature and concentration of various activators on mechanical and microstructural properties of geopolymers. Aqueous solutions of Ca(OH){sub 2}, NaOH, NaOH + Na{sub 2}CO{sub 3}, KOH and sodium silicate (water glass) of various concentrations were used as alkali activators. It was established that the nature and concentration of the activator was the most dominant parameter in the alkali-activation process. In respect of physical characteristics of FA, the key parameter was fineness. The geopolymer based on FA with the highest content of fine particles (<43 {mu}m), showed the highest compressive strength in all cases. Regardless of FA characteristics, nature and concentration of the activator, the alkali-activation products were mainly amorphous. The formation of crystalline phases (zeolites) occurred in some cases, depending on the reaction conditions. The highest compressive strength was obtained using sodium silicate. Together with the increase of sodium silicate SiO{sub 2}/Na{sub 2}O mass ratio, the atomic Si/Al ratio in the reaction products was also increased. Under the experimental conditions of this investigation, high strength was directly related to the high Si/Al ratio.

  20. Mechanical Properties and Eco-Efficiency of Steel Fiber Reinforced Alkali-Activated Slag Concrete

    OpenAIRE

    Sun-Woo Kim; Seok-Joon Jang; Dae-Hyun Kang; Kyung-Lim Ahn; Hyun-Do Yun

    2015-01-01

    Conventional concrete production that uses ordinary Portland cement (OPC) as a binder seems unsustainable due to its high energy consumption, natural resource exhaustion and huge carbon dioxide (CO2) emissions. To transform the conventional process of concrete production to a more sustainable process, the replacement of high energy-consumptive PC with new binders such as fly ash and alkali-activated slag (AAS) from available industrial by-products has been recognized as an alternative. This p...

  1. A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production.

    Science.gov (United States)

    Liu, Guangli; Zhou, Ying; Luo, Haiping; Cheng, Xing; Zhang, Renduo; Teng, Wenkai

    2015-12-01

    The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4 ± 0.6 mmol/Lh) and the lowest energy consumption (0.35 ± 0.14 kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors. PMID:26367771

  2. Integrated Electrolysis & Sabatier System for Internal Reforming Regenerative Fuel Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon Space Development Corporation® (Paragon) will advance our Solid Oxide Electrolysis / embedded Sabatier reactors (SOE/ESR) system to generate power from...

  3. High Temperature Steam Electrolysis: Demonstration of Improved Long-Term Performance

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; X. Zhang; R. C. O' Brien; G. Tao

    2011-11-01

    Long-term performance is an ongoing issue for hydrogen production based on high-temperature steam electrolysis (HTSE). For commercial deployment, solid-oxide electrolysis stacks must achieve high performance with long-term degradation rates of {approx}0.5%/1000 hours or lower. Significant progress has been achieved toward this goal over the past few years. This paper will provide details of progress achieved under the Idaho National Laboratory high temperature electrolysis research program. Recent long-term stack tests have achieved high initial performance with degradation rates less than 5%/khr. These tests utilize internally manifolded stacks with electrode-supported cells. The cell material sets are optimized for the electrolysis mode of operation. Details of the cells and stacks will be provided along with details of the test apparatus, procedures, and results.

  4. Procedure and technique critique for tritium enrichment by electrolysis at the IAEA Laboratory (effective November 1976)

    International Nuclear Information System (INIS)

    This publication gives a detailed description of the experimental and calculation procedures for tritium enrichment. Most descriptive sections are divided into 2 parts: Section A describes the procedure in the IAEA laboratory; section B discusses the reasons behind the various procedures, and may indicate alternative acceptable, or in some cases even better, procedures. The description of the equipment focuses on electrolysis cells, cooling system and power supply. Routine procedures are discussed including handling and checking of samples after receipt, 'spike' and blank water, initial sample distillation, preparation of cells and samples for electrolysis, electrolysis and completion of electrolysis (weighing of cells, neutralisation and distillation) and precautions against contaminations (prevention, detection and cure). A list of equipment required for electrolytic enrichment of tritium is provided

  5. Water electrolysis-induced optical degradation of aluminum-doped zinc oxide films

    International Nuclear Information System (INIS)

    A type of optical degradation of aluminium-doped zinc oxide (AZO) films due to water electrolysis-induced reduction reaction was reported. An experiment was designed in which AZO films were immersed in a 0.01 M NaOH aqueous solution as cathode to electrolyze water. Significant decreases in the optical transmission of the treated samples were observed. Studies by X-ray diffraction and scanning electron microscope showed that the degradation of AZO films was due to compositional and structural changes with the treatment of water electrolysis, which resulted from the reduction reaction of atomic hydrogen generated in the electrolysis of water. This optical degradation reflects the stability degradation of AZO films under water electrolysis environment

  6. THE HIGH-TEMPERATURE ELECTROLYSIS PROGRAM AT THE IDAHO NATIONAL LABORATORY: OBSERVATIONS ON PERFORMANCE DEGRADATION

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien; C. M. Stoots; J. S. Herring; K. G. Condie; G. K. Housley

    2009-06-01

    This paper presents an overview of the high-temperature electrolysis research and development program at the Idaho National Laboratory, with selected observations of electrolysis cell degradation at the single-cell, small stack and large facility scales. The objective of the INL program is to address the technical and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for hydrogen production from steam. In the envisioned application, high-temperature electrolysis would be coupled to an advanced nuclear reactor for efficient large-scale non-fossil non-greenhouse-gas hydrogen production. The program supports a broad range of activities including small bench-scale experiments, larger scale technology demonstrations, detailed computational fluid dynamic modeling, and system modeling. A summary of the current status of these activities and future plans will be provided, with a focus on the problem of cell and stack degradation.

  7. Cathode development for solid oxide electrolysis cells for high temperature hydrogen production

    OpenAIRE

    Yang, Xuedi

    2010-01-01

    This study has been mainly focused on high temperature solid oxide electrolysis cells (HT-SOECs) for steam electrolysis. The compositions, microstructures and metal catalysts for SOEC cathodes based on (La₀.₇₅Sr₀.₂₅)₀.₉₅Mn₀.₅Cr₀.₅O₃ (LSCM) have been investigated. Hydrogen production amounts from SOECs with LSCM cathodes have been detected and current-to-hydrogen efficiencies have been calculated. The effect of humidity on electrochemical performances from SOECs with cathodes ba...

  8. High Temperature Water Electrolysis Using Metal Supported Solid Oxide Electrolyzer Cells (SOEC)

    OpenAIRE

    Schiller, Günter; Ansar, Asif Syed; Patz, Olaf

    2010-01-01

    Metal supported cells as developed at DLR for use as solid oxide fuel cells by applying plasma deposition technologies were investigated in operation of high temperature steam electrolysis. The cells consisted of a porous ferritic steel support, a diffusion barrier layer, a Ni/YSZ fuel electrode, a YSZ electrolyte and a LSCF oxygen electrode. During fuel cell and electrolysis operation the cells were electrochemically characterized by means of i-V characteristics and electrochemical impedance...

  9. Porous poly(perfluorosulfonic acid) membranes for alkaline water electrolysis

    DEFF Research Database (Denmark)

    Aili, David; Hansen, Martin Kalmar; Andreasen, Jens Wenzel;

    2015-01-01

    Poly(perfluorosulfonic acid) (PFSA) is one of a few polymer types that combine excellent alkali resistance with extreme hydrophilicity. It is therefore of interest as a base material in separators for alkaline water electrolyzers. In the pristine form it, however, shows high cation selectivity. To...... increase its ion conductivity in aqueous KOH, a method for the preparation of porous PFSA membranes was developed. It was based on an approach where PFSA was co-cast with poly(vinylpyrrolidone) (PVP) at different ratios to give transparent and colorless blend membranes. The PVP was subsequently dissolved...

  10. Superconductivity in alkali metal intercalated iron selenides.

    Science.gov (United States)

    Krzton-Maziopa, A; Svitlyk, V; Pomjakushina, E; Puzniak, R; Conder, K

    2016-07-27

    Alkali metal intercalated iron selenide superconductors A x Fe2-y Se2 (where A  =  K, Rb, Cs, Tl/K, and Tl/Rb) are characterized by several unique properties, which were not revealed in other superconducting materials. The compounds crystallize in overall simple layered structure with FeSe layers intercalated with alkali metal. The structure turned out to be pretty complex as the existing Fe-vacancies order below ~550 K, which further leads to an antiferromagnetic ordering with Néel temperature fairly above room temperature. At even lower temperatures a phase separation is observed. While one of these phases stays magnetic down to the lowest temperatures the second is becoming superconducting below ~30 K. All these effects give rise to complex relationships between the structure, magnetism and superconductivity. In particular the iron vacancy ordering, linked with a long-range magnetic order and a mesoscopic phase separation, is assumed to be an intrinsic property of the system. Since the discovery of superconductivity in those compounds in 2010 they were investigated very extensively. Results of the studies conducted using a variety of experimental techniques and performed during the last five years were published in hundreds of reports. The present paper reviews scientific work concerning methods of synthesis and crystal growth, structural and superconducting properties as well as pressure investigations. PMID:27248118

  11. Durability of Alkali Activated Blast Furnace Slag

    Science.gov (United States)

    Ellis, K.; Alharbi, N.; Matheu, P. S.; Varela, B.; Hailstone, R.

    2015-11-01

    The alkali activation of blast furnace slag has the potential to reduce the environmental impact of cementitious materials and to be applied in geographic zones where weather is a factor that negatively affects performance of materials based on Ordinary Portland Cement. The scientific literature provides many examples of alkali activated slag with high compressive strengths; however research into the durability and resistance to aggressive environments is still necessary for applications in harsh weather conditions. In this study two design mixes of blast furnace slag with mine tailings were activated with a potassium based solution. The design mixes were characterized by scanning electron microscopy, BET analysis and compressive strength testing. Freeze-thaw testing up to 100 freeze-thaw cycles was performed in 10% road salt solution. Our findings included compressive strength of up to 100 MPa after 28 days of curing and 120 MPa after freeze-thaw testing. The relationship between pore size, compressive strength, and compressive strength after freeze-thaw was explored.

  12. Superconductivity in alkali metal intercalated iron selenides

    Science.gov (United States)

    Krzton-Maziopa, A.; Svitlyk, V.; Pomjakushina, E.; Puzniak, R.; Conder, K.

    2016-07-01

    Alkali metal intercalated iron selenide superconductors A x Fe2‑y Se2 (where A  =  K, Rb, Cs, Tl/K, and Tl/Rb) are characterized by several unique properties, which were not revealed in other superconducting materials. The compounds crystallize in overall simple layered structure with FeSe layers intercalated with alkali metal. The structure turned out to be pretty complex as the existing Fe-vacancies order below ~550 K, which further leads to an antiferromagnetic ordering with Néel temperature fairly above room temperature. At even lower temperatures a phase separation is observed. While one of these phases stays magnetic down to the lowest temperatures the second is becoming superconducting below ~30 K. All these effects give rise to complex relationships between the structure, magnetism and superconductivity. In particular the iron vacancy ordering, linked with a long-range magnetic order and a mesoscopic phase separation, is assumed to be an intrinsic property of the system. Since the discovery of superconductivity in those compounds in 2010 they were investigated very extensively. Results of the studies conducted using a variety of experimental techniques and performed during the last five years were published in hundreds of reports. The present paper reviews scientific work concerning methods of synthesis and crystal growth, structural and superconducting properties as well as pressure investigations.

  13. High-Order Dispersion Coefficients for Alkali-metal Atoms

    Institute of Scientific and Technical Information of China (English)

    KANG Shuai; DING Chi-Kun; CHEN Chang-Yong; WU Xue-Qing

    2013-01-01

    High-order dispersion coefficients C9,C11,C12,and C13 for the ground-state alkali-metals were calculated by combining the l-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions.The results were compared.

  14. High performance of nitrogen and phosphorus removal in an electrolysis-integrated biofilter.

    Science.gov (United States)

    Gao, Y; Xie, Y W; Zhang, Q; Yu, Y X; Yang, L Y

    2016-01-01

    A novel electrolysis-integrated biofilter system was developed in this study to evaluate the intensified removal of nitrogen and phosphorus from contaminated water. Two laboratory-scale biofilter systems were established, one with electrolysis (E-BF) and one without electrolysis (BF) as control. The dynamics of intensified nitrogen and phosphorus removal and the changes of inflow and outflow water qualities were also evaluated. The total nitrogen (TN) removal rate was 94.4% in our newly developed E-BF, but only 74.7% in the control BF. Ammonium removal rate was up to 95% in biofilters with or without electrolysis integration with an influent ammonium concentration of 40 mg/L, and the accumulation of nitrate and nitrite was much lower in the effluent of E-BF than that of BF. Thus electrolysis plays an important role in TN removal especially the nitrate and nitrite removal. Phosphorus removal was significantly enhanced, exceeding 90% in E-BF by chemical precipitation, physical adsorption, and flocculation of phosphorus because of the in situ formation of ferric ions by the anodizing of sacrificial iron anodes. Results from this study indicate that the electrolysis integrated biofilter is a promising solution for intensified nitrogen and phosphorus removal. PMID:27508376

  15. H{sub 2} production by PEM electrolysis, assisted by textile effluent treatment and a solar photovoltaic cell

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Solis, Isabel; Villalba-Almendra, Lilia; Alvarez-Gallegos, Alberto [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos (UAEM), Av Universidad 1001, Campus Chamilpa, Cuernavaca, Morelos (Mexico)

    2010-10-15

    In this paper a new approach for H{sub 2} production by PEM electrolysis, assisted by effluent treatment in the anolyte is proposed. H{sub 2} is produced, in the catholyte, by proton reduction at a Fe-cathode, in an acid medium (1 M H{sub 2}SO{sub 4}). While in the anolyte, a mixture of Fe{sup 2+}/Fe{sup 3+} is produced from the oxidation of an iron anode. The overall energy required ({<=}1.00 V) is less than that required by conventional water electrolysis, and is delivered by solar panels. In the anolyte, iron ions can be used in favor of a Fenton-type process, in the presence of H{sub 2}O{sub 2}. This approach is used in effluent treatment. The oxidation efficiency of dyes reactive black 5 (RB 5) and acid green 25 (AG 25) was investigated, in mild conditions, during H{sub 2} production. The main experimental results show that it is possible to oxidize 0.00024 M RB 5 or 0.0002 M AG 25 in the anolyte, in 20 min. (author)

  16. Effects of alkali treatments on Ag nanowire transparent conductive films

    Science.gov (United States)

    Kim, Sunho; Kang, Jun-gu; Eom, Tae-yil; Moon, Bongjin; Lee, Hoo-Jeong

    2016-06-01

    In this study, we employ various alkali materials (alkali metals with different base strengths, and ammonia gas and solution) to improve the conductivity of silver nanowire (Ag NW)-networked films. The alkali treatment appears to remove the surface oxide and improve the conductivity. When applied with TiO2 nanoparticles, the treatment appears more effective as the alkalis gather around wire junctions and help them weld to each other via heat emitted from the reduction reaction. The ammonia solution treatment is found to be quick and aggressive, damaging the wires severely in the case of excessive treatment. On the other hand, the ammonia gas treatment seems much less aggressive and does not damage the wires even after a long exposure. The results of this study highlight the effectiveness of the alkali treatment in improving of the conductivity of Ag NW-networked transparent conductive films.

  17. Alkali absorption and citrate excretion in calcium nephrolithiasis

    Science.gov (United States)

    Sakhaee, K.; Williams, R. H.; Oh, M. S.; Padalino, P.; Adams-Huet, B.; Whitson, P.; Pak, C. Y.

    1993-01-01

    The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p mEq/day). Both urinary citrate and net GI alkali absorption increased, yielding a significantly positive correlation (r = 0.62, p reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

  18. Performance of Straight Steel Fibres Reinforced Alkali Activated Concrete

    Science.gov (United States)

    Faris, Meor Ahmad; Bakri Abdullah, Mohd Mustafa Al; Nizar Ismail, Khairul; Muniandy, Ratnasamy; Putra Jaya, Ramadhansyah

    2016-06-01

    This paper focus on the performance of alkali activated concrete produced by using fly ash activated by sodium silicate and sodium hydroxide solutions. These alkali activated concrete were reinforced with straight steel fibres with different weight percentage starting from 0 % up to 5 %. Chemical composition of raw material in the production alkali activated concrete which is fly ash was first identified by using X-ray fluorescence. Results reveal there have an effect of straight steel fibres inclusion to the alkali activated concrete. Highest compressive strength of alkali activated concrete which is 67.72 MPa was obtained when 3 % of straight fibres were added. As well as flexural strength, highest flexural strength which is 6.78 MPa was obtained at 3 % of straight steel fibres inclusions.

  19. Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources

    International Nuclear Information System (INIS)

    High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 C to 950 C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered

  20. Parametric evaluation of large-scale high-temperature electrolysis hydrogen production using different advanced nuclear reactor heat sources

    International Nuclear Information System (INIS)

    High-temperature electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800-950 oC, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an intermediate heat exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed with the objective of evaluating the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency of the integrated plant design for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.