scholarly journals LONG-TERM OXIDATION STABILITY OF GASOLINE ON ACCOUNT OF MIR MONITORING

Transport ◽  
2006 ◽  
Vol 21 (3) ◽  
pp. 218-222 ◽  
Author(s):  
Arunas Andziulis

The problem of oxidation stability of petroleum products often arises under the protracted transportation or tankage of products in the maritime terminal storages or in the national repositories for a prolonged time. So, this paper presents the results of study of auto‐oxidation kinetics of hydrocarbons in the gasoline, carried out by applying the method of middle range IR spectroscopy (MIR) monitoring aimed at the prediction of fuel oxidation stability. The results of study enabled to propose the virtual chemometrical model based on the MIR spectrum analysis which was applicable for testers which register the changes in concentration of olefins. As the object of research there was taken the gasoline which was carrying JV; > 50–90 of different structures of C2‐C10 olefins in unordered set of hydrocarbons which degrade the petroleum product.

2009 ◽  
Vol 63 (9) ◽  
pp. 1008-1014 ◽  
Author(s):  
Tsunetake Seki ◽  
Jean-Michel Andanson ◽  
Fabian Jutz ◽  
Alfons Baiker

The CO2-catalyzed acetalization is regarded as a promising alternative to the conventional acid-catalyzed method from a viewpoint of green chemistry (C. A. Eckert et al., Ind. Eng. Chem. Res. 43, 2605 (2004)). We have applied in situ attenuated total reflection infrared (ATR-IR) spectroscopy for elucidating and monitoring the acetalization of cyclohexanone in CO2-expanded ethylene glycol and methanol at 50 °C and 3 MPa. The ATR-IR spectra of the reaction mixtures periodically recorded with a ZnSe crystal demonstrate that ATR-IR spectroscopy is a practical tool for tracing the kinetics of acetalizations in situ. In addition, the rate of CO2 dissolution as well as CO2 solubility into the cyclohexanone–alcohol mixtures could be evaluated from the CO2-v3-antisymmetric stretching band. The ZnSe ATR crystal, however, was corroded during longer use under the acidic conditions realized by the dissolution of CO2 in the alcohols. In contrast, the corrosion did not occur when a Ge crystal was used instead of a ZnSe crystal, and therefore the application of a Ge ATR crystal is recommended for continuous long-term experiments with these media.


Author(s):  
Sergey V. Sereda ◽  
◽  
Alexander Y. Lyapin ◽  
Egor S. Dubovoy ◽  
Fedor V. Timofeev ◽  
...  

Comparative analysis of in-line monitoring methods to determine the boundaries of the mixture region of petroleum products transported by serial transfer has been carried out. It has been found that the most promising method is infrared spectroscopy (IR spectroscopy) based on the absorption, reflection and dispersion of infrared energy. Currently, the use of IR spectroscopy for analyzing petroleum products is limited by an insufficient number of indirect methods for identifying and determining the structural fragments of hydrocarbon and non-hydrocarbon compounds. Experimental studies to assess the possibility of applying IR spectroscopy as a rapid method for determining the boundaries of mixture regions of various grades of petroleum products have been conducted. The purpose of the research: quantifying variations of IR spectra obtained from the analyzed test samples depending on the concentration of a certain grade of petroleum product in a petroleum product with a different hydrocarbon composition. The subject of the research: samples of AI-95 commercial motor gasoline (AB), inter-season diesel fuel (DT), TS-1 aviation kerosene (AK), and 1:1 ratio paired mixture thereof. The experimental results confirmed the high sensitivity of the IR spectroscopy method in determining changes to the hydrocarbon composition of petroleum product mixtures depending on the concentration thereof, which means a key conclusion about the possibi-lity of its use in controlling the mixing process of petroleum productstransported by serial transfer can be drawn.


2005 ◽  
Vol 21 (10) ◽  
pp. 1111-1118 ◽  
Author(s):  
Z. D. Xiang ◽  
S. R. Rose ◽  
P. K. Datta

1996 ◽  
Vol 446 ◽  
Author(s):  
D. Manessis ◽  
H. Du

AbstractOxidation stability of silicon oxynitride is a property of great technological significance. In this study, the oxidation behavior of stoichiometric polycrystalline Si2N2O was investigated in 1 and 0.5 atm flowing dry oxygen at 1000°‐1300°C. The oxidized Si2N2O samples were characterized using transmission and scanning electron microscopy. The oxidation kinetics were determined using profilometry in conjunction with patterned etching. Oxidation of Si2N2O resulted in the formation of amorphous SiO2. The SiO2‐Si2N2O interface was chemically and structurally abrupt. A parabolic rate law was followed during oxidation with apparent activation energies ranging from 43 to 52 kcal/mol. The relatively high activation energy values compared to that for silicon oxidation suggest that oxidation of Si2N2O is rate‐controlled by a more complex process than molecular oxygen diffusion in amorphous SiO2.


Equilibrium ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 315-339
Author(s):  
Leonid Galchynskyi

Research background: The analysts of the petroleum product markets of industrial countries believe that the elasticity of demand varies at different periods, which gave rise to the hypothesis that behavioral and structural factors have changed the consumers’ reaction during the last few decades, with a change in prices of petroleum products. Purpose of the article: The purpose of this article is to study the elasticity of demand and prices in order to identify changes in consumer behavior in the oil market after significant socio-economic shocks and to establish a correlation between changes in elasticity and price volatility, with the Ukrainian petroleum products market as an illustrative example. Methods: Based on the time series of the petroleum product market of Ukraine, static and dynamic models for assessing the demand elasticity were constructed. It was found that the time series of demand for petroleum products is non-stationary but then the time series of the first differences is stationary according to the extended Dickey-Fuller test; further, the fact of co-integration between time series of consumption, income, and prices was established by the Johansson test. This made it possible to construct co-integration dependence, allowing, in turn, the development of models for assessing the elasticity of demand for petroleum products, on the basis of which objective assessments of changes in consumer behavior were established. Analysis of the monthly calculation of petroleum products’ price volatility during the period 2008 to 2018 has showed that the values of volatility increased abnormally in the period between the beginning of 2014 and the middle of 2015. The estimates of price and demand elasticities obtained for the two periods up to the beginning of 2014 and the second half of 2015 differ significantly from the values of the corresponding elasticities between the beginning of 2014 and the middle of 2015. Findings & Value added: Assessments of income elasticities and price elasticities for petroleum products in the Ukrainian market were obtained by three co-integration models, both short and long term, for each of the three previously defined time intervals. In one of them, characterized by a high level of price volatility conditionally referred to as a crisis, the value of elasticities differed markedly from the corresponding values in the other two periods, in particular, -0.383 for price elasticity and 1.068 for a long-term bond. In the other two periods, these were, respectively, 0.543 for price elasticity and 0.274 for long-term pre-crisis elasticity, and -0.470 for price elasticity and 0.235 for long-term post-crisis elasticity. Appropriate elasticity estimates were obtained for both the short-run and the dynamic model, for the same defined intervals. A comparison of these estimates showed the closeness of the values of elasticities for the pre-crisis and post-crisis intervals and a marked difference from the estimates of the elasticities in the crisis interval. Thus, it was found that a significant change in elasticities is accompanied by an increase in price volatility.


1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).


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