Scientific Bases of Water Chemistry for Corrosion Control of NPPs by Integration of Radiation- and Electro-Chemistry

2013 ◽  
Author(s):  
Genn Saji
Keyword(s):  
Hydrogen Peroxide ◽  
Water Chemistry ◽  
Material Balance ◽  
Scientific Basis ◽  
Experimental Results ◽  
Basic Material ◽  
General Interest ◽  
Recent Theory ◽  
Radiation Chemical ◽  
Corrosion Science

In this paper, the author continues his investigation on the scientific basis of water chemistry specifications by applying his recent theory, which integrates the elemental radiation- and electro-chemistry reactions in the “Butlar-Volmer equation.” The B-V equation is well established as the basic material balance equation in corrosion science. The author’s new approach has been compared with the published in-pile test results of the electrochemical potential differences between the in-flux and out-flux regions for both the PWR- and BWR water chemistry environment. Although the theoretical estimation generally reproduced the experimental results, there remains significant deviation from the experimental results at the very low DH region (<10cc-STP/kg-water) in PWRs as well as the low DO region (<10ppb) in BWRs. Although these regions are outside of the water chemistry specifications of general interest, the scientific causes of the deviation must be clarified. In this paper, the author found that the deviations are due to the dominant radiation-chemical reactions involving hydrogen ions and hydrogen peroxide at the lower ends. Although the radiation- and electrochemical reaction was further exploited with respect to the potential differences induced by the hydrogen peroxide, the effects were disappointingly small, when estimated in terms of a mixed potential of the electrode reactions. This leads the author to suspect that hydrogen-ion-radical reactions should be the main causes. Currently further analyses are in progress.

Characterization of In-Core Water Chemistry for Corrosion Control of LWRs

2014 ◽  
Author(s):  
Genn Saji
Keyword(s):  
Redox Potential ◽  
Water Chemistry ◽  
Single Point ◽  
Experimental Results ◽  
Potential Difference ◽  
Corrosion Mechanism ◽  
Recent Theory ◽  
Scientific Validity ◽  
Pile Test ◽  
Test Loop

This paper updates scientific bases of water chemistry in applying the author’s recent theory, which integrates the elemental radiation- and electro-chemistry reactions in the “Butlar-Volmer equation,” presented in ICONE21-16525. For the past several years the author has been trying to establish that the “long-cell” (a kin to macro-cell) corrosion mechanism is inducing practically all sorts of accelerated corrosion phenomena widely observed in water-cooled reactors, especially in aged plants. The theoretical electrochemical potential differences have been benchmarked with the published in-pile test results for both PWR- and BWR water chemistry environments. However the author’s previous verification efforts were limited to the extent that the curves were fitted with experimental results at a single point. The author re-formulated the basic theory and found that the redox potential difference consists of an electrochemical part (e.g., Nernst equation of dissolved hydrogen or oxygen) and radiation-induced perturbation term, the latter diminishes to zero without radiation. The author continued his studies to clarify whether our current scientific knowledge is sufficient to explain the in-core “chemistry” to reproduce the experimental results without the fitting parameter. Through his study he realized that the basic mechanism of the potential difference is still not sufficiently known. No fitting parameter was used for the PWR water chemistry in the DH region for practical engineering applications, although it is indispensable to confirm the results with an in-pile test loop. In the BWR-NWC the theoretical redox potential out of core was still necessary to be fitted with the experimental results, due to an effect of residual hydrogen peroxide detected by the reference electrode. In addition the calculated potential shift is several times larger than the experimental observation. With the reformulation the scientific validity of the author’s theory is further confirmed. He believes that there is no doubt that the “long-cell” takes place in LWRs, although details are still debatable.

60Co γ radiolysis of reduced glutathione in aerated solutions at pH values between 1–7.0

1976 ◽  
Vol 54 (7) ◽  
pp. 1092-1097 ◽  
Author(s):  
Manohar Lal
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Mechanism ◽  
Reduced Glutathione ◽  
Material Balance ◽  
Experimental Results ◽  
Chain Reaction ◽  
Ph Values ◽  
Sh Group ◽  
Small Chain ◽  
Good Agreement

G-values for the formation of oxidised glutathione (GuS—SGu), glutathione sulphinic acid (GuSO2H), γ-glutamylalanylglycine (GuH), γ-glutamylserylglycine (GuOH), and hydrogen peroxide and G(—GuSH) have been estimated in the γ-radiolysis of aerated reduced glutathione solutions at pH values between 1–7.3. The results show excellent material balance for the radiolytic amino products. Oxygen is necessary for the production of both glutathione sulphinic acid and γ-glutamylserylglycine in the radiolysis of glutathione. Product yields increase with increasing GuSH concentration and reflect the occurrence of a small chain reaction. Although the spectrum of amino products is identical to the corresponding products from cysteine radiolysis under similar conditions, their yields are very much different. It is significant, that there is no evidence for the scission of the peptide chain, at any of the GuSH concentrations and pH's; thus the —SH group of glutathione is the site of attack of the primary species.A reaction mechanism, which explains most of the experimental results has been put forward. A rate expression for G(—GuSH) has been evaluated and it is found that the experimental and calculated G(—GuSH) are in good agreement.

scholarly journals Calcium‐Bearing Minerals Transformation during Underground Coal Gasification

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 708 ◽  
Author(s):  
Liu ◽  
Ma
Keyword(s):  
Coal Gasification ◽  
Ternary Phase Diagram ◽  
Energy Dispersive Spectrometer ◽  
Coal Ash ◽  
Scientific Basis ◽  
Experimental Results ◽  
Underground Coal Gasification ◽  
Morphological Transformation ◽  
Reaction Conditions ◽  
High Calcium

Calcium‐bearing minerals are one of the main typical minerals in coal and coal ash. In the process of coal thermal conversion, calcium‐bearing minerals undergo different morphological transformation in which the reaction temperature, pressure, and atmosphere are important factors affecting their transformation. The reaction process of underground coal gasification (UCG) could be clearly divided into pyrolysis, reduction, and oxidation and the typical calcium‐bearing minerals are expected to indicate the actual reaction conditions of UCG. A high‐calcium coal, Zhundong coal, was used in this research. The products of UCG were prepared and the minerals were identified by X‐ray diffraction (XRD) and a scanning electron microscope coupled with an energy‐dispersive spectrometer (SEM‐EDS). The thermodynamic calculation was used to assist in understanding the transformation behaviors of calcium‐bearing minerals. The experimental results show that the calcium‐bearing mineral is gradually converted from gypsum (CaSO4·2H2O) in the raw coal into anhydrite (CaSO4) during the pyrolysis process. In the reduction stage, anhydrite reacts with the reducing gas (CO) to produce oldhamite (CaS), and the oldhamite is stably present in the reduction ash. During the oxidation process, oldhamite is first transformed into CaSO4, and then CaSO4 is converted into CaO. Finally, CaO reacts with Al2O3 and SiO2 to produce gehlenite (Ca2Al2SiO7) at 1100 °C. As the oxidation temperature rises to 1400 °C, gehlenite is transformed into the thermodynamically stable anorthite (CaAl2Si2O8). With the further progress of the reaction, anorthite will co‐melt with iron‐bearing minerals above 1500 °C. The ternary phase diagram of SiO2–Al2O3–CaO system proves that anorthite and gehlenite are the typical high‐temperature calcium‐bearing minerals when the mole fraction of SiO2 is higher than 0.6. Moreover, the gehlenite is converted to anorthite with the temperature rise, which is consistent with experimental results. This study provides a scientific basis for understanding the UCG reaction conditions.

Quick estimation of product yields from downhole gas sample

2012 ◽  
Vol 52 (2) ◽  
pp. 640
Author(s):  
Mike Jones
Keyword(s):  
Material Balance ◽  
Gas Analysis ◽  
Basic Material ◽  
Accurate Estimation ◽  
Simple Material ◽  
Simple Method ◽  
Heating Value ◽  
Product Yields ◽  
Product Stream ◽  
The Individual

The estimation of product yields from gas and gas condensate reservoirs is often the subject of multi-million-dollar studies, requiring gas and condensate samples from production tests, lab analysis of the samples, and complex process engineering models. An accurate estimation of sales product yields can, however, be determined simply from the composition of a reservoir sample and a basic material balance calculation. Sales gas, LNG, and condensate have fairly consistent specifications across the world, based on various properties such as heating value, vapour pressure, etc. This consistency allows the determination of product yields from simple material balance calculations and properties of the individual components found in the reservoir gas. In this case, material balance simply means the allocation of each component to a particular product stream. The lighter components, C1 through C4 (methane through butane), comprise the LNG and/or sales gas product, and all C5+ (pentane and heavier) components make up the condensate product. The yields can then calculated for each unit of reservoir gas, for example MJ/scm, BTU/scf, bbl/MMscf, etc. Inerts such as CO2 and N2 have no heating value and are not included in the yield calculation. Likewise, contaminants such as H2S must be removed from the product stream and are not included in the yield. In actual practice, a perfect separation of the individual components is not achieved—that is,the condensate product will contain small amounts of C3 and C4, but experience has shown that the simple method described above gives an accurate estimattion of product yields from a simple gas analysis.

THE HETEROGENEOUS CATALYTIC DECOMPOSITION OF HYDROGEN PEROXIDE IN HEAVY WATER

1940 ◽  
Vol 18b (3) ◽  
pp. 84-89 ◽  
Author(s):  
P. A. Giguère ◽  
O. Maass
Keyword(s):  
Hydrogen Peroxide ◽  
Alkaline Medium ◽  
Heavy Water ◽  
Catalytic Decomposition ◽  
Metallic Gold ◽  
Experimental Results ◽  
Ordinary Water ◽  
Heterogeneous Catalytic

The catalytic decomposition of hydrogen peroxide dissolved in heavy water, both on the surface of glass in alkaline medium and on metallic gold, was measured at 35 °C. The results, compared with those obtained under similar conditions for hydrogen peroxide in ordinary water, indicate that deuterium peroxide (D2O2) is much more stable than ordinary hydrogen peroxide towards such catalysts. The experimental results in both cases are of interest chiefly for comparison, and further investigations will be necessary before any sound conclusion can be drawn regarding the mechanism of the reactions involved.

scholarly journals Modeling and Simulation of Gas Liquid Absorption Column for So2 Removal Process

2019 ◽  
Vol 8 (6S2) ◽  
pp. 528-530
Keyword(s):  
Hydrogen Peroxide ◽  
Flue Gas ◽  
Sulphur Dioxide ◽  
Coal Combustion ◽  
Material Balance ◽  
Absorption Column ◽  
So2 Removal ◽  
Adverse Impacts ◽  
Liquid Absorption ◽  
Harmful Effects

During coal combustion, sulphur in the coal is converted into sulphur dioxide (SO2).This sulphur dioxide (SO2) is responsible for the formation of acid rain which is one of the widespread forms of pollution all over the world that causes harmful effects to humans and environment. To minimize the adverse impacts of SO2, it must be removed from flue gas. For reduction of SO2, flue gas desulphurization (FGD) is most commonly used. The mathematical viewer is developed and simulated for a gas liquid absorption column to control the flow rate of H2O2.The model equation is developed by considering material balance around the column. The absorption rate is determined by using different concentration of sulphur dioxide with hydrogen peroxide. Hydrogen peroxide, not only absorbs the SO2 but it also produce useful by-product in the form of sulphuric acid (H2SO4).

scholarly journals Analysis of flow coefficient in chair manufacture

2005 ◽  
pp. 43-53
Author(s):  
Dragoljub Ivkovic ◽  
Slaven Zivkovic
Keyword(s):  
Manufacturing Process ◽  
Scientific Basis ◽  
Flow Coefficient ◽  
Basic Material ◽  
Production Cycle ◽  
Parallel Method ◽  
Process Duration ◽  
Complex Construction ◽  
Sawn Timber ◽  
Method Of Production

The delivery on time is not possible without the good-quality planning of deadlines, i.e. planning of the manufacturing process duration. The study of flow coefficient enables the realistic forecasting of the manufacturing process duration. This paper points to the significance of the study of flow coefficient on scientific basis so as to determine the terms of the end of the manufacture of chairs made of sawn timber. Chairs are the products of complex construction, often almost completely made of sawn timber as the basic material. They belong to the group of export products, so it is especially significant to analyze the duration of the production cycle, and the type and the degree of stoppages in this type of production. Parallel method of production is applied in chair manufacture. The study shows that the value of flow coefficient is close to one or higher, in most cases. The results indicate that the percentage of interoperational stoppage is unjustifiably high, so it is proposed how to decrease the percentage of stoppages in the manufacturing process.

scholarly journals Natural antibacterial characteristics of honey

2004 ◽  
Vol 58 (3-4) ◽  
pp. 377-383
Author(s):  
Dragana Pesic-Mikulec ◽  
Nada Dugalic-Vrndic ◽  
Milan Baltic
Keyword(s):  
Hydrogen Peroxide ◽  
Veterinary Medicine ◽  
Traditional Medicine ◽  
19Th Century ◽  
Skin Diseases ◽  
Experimental Results ◽  
Intestinal Infections ◽  
Ancient Times ◽  
The 19Th Century

Honey was used as a medicine in traditional medicine of the Ancient Times ever since the age of Hippocrates. Scientifically based investigations of the medicinal qualities of honey date back to the 19th century. There have been constant polemics, about the medicinal characteristics of honey and parameters that cause them, among scientists and apiculture experts. In this paper, we processed much data from literature, which indicate the antibacterial characteristics of honey through the experimental results that have been presented. The factors which lead to honey possessing these characteristics are: somotic effect, acidity, effect of hydrogen peroxide and others. The priority in today?s investigations is to prove the effects and safety of using honey as an alternative to conventional forms of treatment of skin diseases, gastro-intestinal infections in the area of medicine, and the treatment of mastitis and wounds in the area of veterinary medicine.

One-Step Synthesis of Lemonile from Citral by Liquid Phase Catalytic Ammoxidation

2013 ◽  
Vol 641-642 ◽  
pp. 959-961
Author(s):  
Ye Wang ◽  
Shao Feng Pi ◽  
Jin Hua Zhou ◽  
Hai Li Gao ◽  
Ji Lie Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Liquid Phase ◽  
Green Synthesis ◽  
New Technology ◽  
Reaction System ◽  
Experimental Results ◽  
Optimal Conditions ◽  
One Step

Lemonile is a new kind of spice. The new technology for synthesis of lemonile from citral by catalytic ammoxidation has been investigated. Experimental results showed the optimal synthetic conditions are as follows. The molar material ratio n(H2O2):n(Citral) is 3:1, solvent for the reaction is isopropanol, dosage of the catalyst CuCl is 3% (wt, calculated by citral), the drop-feeding temperature and time for hydrogen peroxide are 10 °C-14 °C and 3 hrs, respectively; after hydrogen peroxide being drop-fed into the reaction system, the reaction should be continued for 4 hrs. Lemonile yield is 91.2% and purity is 98.5% (detected by GC) under the optimal conditions. This new one-step liquid phase catalytic ammoxidation technology is a green synthesis way for lemonile. The structure of the product has been confirmed by GC-MS.

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