The paper reports the results of a kinetic modeling and thermodynamic analysis of non-catalytic steam reforming (NCSR) of methane and C
2
–C
4
hydrocarbons at 1400–1800 K. The hydrocarbon-to-syngas ...conversion sequence and the time periods of the major process steps were identified. The initial step consists of hydrocarbon pyrolysis to acetylene and H
2
with essentially no involvement of H
2
O. Noticeable H
2
O conversion starts at a significantly later point than thermal hydrocarbon conversion, under the effects of radicals formed from the pyrolysis. The H
2
O conversion results in the generation of OH
●
radicals, which subsequently react with acetylene to form CO and H
2
. The key step in the NCSR of C
1
–C
4
hydrocarbons, as well as in their high-temperature interaction with CO
2
(carbon-dioxide conversion) is conversion of the acetylene formed from the hydrocarbon pyrolysis. The study findings are important for the optimization of high-temperature syngas production via partial oxidation of hydrocarbons.
Trials of a combined process of matrix conversion of propane–butane mixture and subsequent catalytic steam conversion of the matrix conversion product gas to a hydrogen-containing gas were performed. ...The optimum ranges of process parameters for the matrix conversion of the propane–butane mixture were determined. Introduction of the additional step of catalytic steam conversion allows improvement of the parameters of the matrix conversion product gas, of which the hydrogen content is the most important parameter.
The development of noncatalytic procedures for processing hydrocarbon gases is an important way to increase the efficiency of gas-chemical processes and decrease their power consumption. The paper ...deals with thermodynamic and kinetic modeling of noncatalytic processes of the partial oxidation and steam and carbon dioxide conversion of methane in the temperature interval 1400–1800 K and with analysis of the process for syngas production by matrix conversion of rich methane–oxygen mixtures. Comparison of the kinetic calculations with the experimental data demonstrated the possibility of applying published models to the description of the matrix conversion of methane. The possibility of developing a highly efficient technology based on noncatalytic partial oxidation of hydrocarbons for the syngas production without СО
2
emission into the environment is discussed.
The kinetic patterns of the attainment of the equilibrium product composition in non-catalytic processes of partial oxidation and of steam and carbon dioxide reforming of hydrocarbons in the ...temperature range 1400–1800 K, characteristic of these processes, were analyzed. The need for such analysis is caused by the rapidly increasing consumption of natural gas as a chemical feedstock and by growing attention to environmental problems, in particular, to a decrease in СО
2
emissions or to partial CO
2
utilization. The forward and reverse water gas shift reactions (WGSRs) play an important role in approach to the equilibrium product composition in these processes. Analysis has shown that the elementary reactions characteristic of forward and reverse WGSRs start to play a significant role long before the equilibrium in the system is attained. Already in the intermediate steps of the process, the distribution of the major reaction products, Н
2
, СО, Н
2
О, and СО
2
, almost corresponds to the equilibrium value of
K
t
= (H
2
CO
2
)/(COH
2
O), close to the WGSR equilibrium constant
K
eq
, and further conversion of the products occurs at
K
t
values close to
K
eq
.
In the experiment with the SND detector at the VEPP-2000
collider, events of the process
were separated via measuring, in each counter of the multichannel calorimeter based on 1640 NaI(Tl) crystals, ...the time of delay of the signal from nonrelativistic antineutrons. The time resolution for events of the process
was 0.8 ns. The measured time spectrum of delays of the signal from antineutrons in the calorimeter at the c.m. energy of 1902 MeV agrees with the results of calculations.
Oxidative Cracking of Oil Refinery Gases Ozerskii, A. V.; Zimin, Ya. S.; Komarov, I. K. ...
Russian journal of applied chemistry,
12/2019, Letnik:
92, Številka:
12
Journal Article
Recenzirano
Trials of oxidative cracking of ethane—propane—
n
-butane mixtures were performed on an installation with the productive capacity with respect to the gaseous feed of 5 m
3
h
−1
. Ethylene, CO, and ...hydrogen are the major products of oxidative cracking of oil refinery gases; their total yield can exceed 90%. The yield of ethylene and CO is determined by the total concentration of alkanes in the mixture and is independent on the length of their hydrocarbon chain, whereas the hydrogen yield appreciably decreases with an increase in the alkane chain length. The trials demonstrated high efficiency of the production of ethylene, CO, and hydrogen by oxidative cracking of oil refinery gas mixture components.
UkrVO Astroinformatics Software and Web-services Vavilova, I. B.; Yatskiv, Ya. S.; Pakuliak, L. K. ...
Proceedings of the International Astronomical Union,
10/2016, Letnik:
12, Številka:
S325
Journal Article
Recenzirano
Odprti dostop
The aim of this paper is to introduce the software and astronomical web-services developed in frame of the Ukraine Virtual Observatory (UkrVO) and VIrtual Roentgen and Gamma Observatory (VIRGO) to ...the broad astronomical community. We report briefly on such web-services as the public databases “Sky Maps” of X-ray observations by XMM-Newton, the Earth Orbital Parameters for International Earth Rotation System, and the UkrVO Joint Digitized Archive of astroplates. We refer to such software as the “Multi-Column View”, “Variable Stars Calculator”, “FrameSmooth” for variable star’s research and “Collection Light Technology” (CoLiTec) software for search and discovery of new Solar System bodies.
The
cross section has been measured in the experiment at the VEPP-2000
collider with the SND detector. The technique of the time measurements in the multichannel NaI(Tl) electromagnetic calorimeter ...is used to select
events. The value of the measured cross section in the energy range from the threshold up to 2 GeV is about 0.5 nb, which corresponds to the value of the neutron effective timelike formfactor ~0.3.
The process
is studied in the range of center-of-mass (c.m.) collision energies between 1.05 and 2.00 GeV on the basis of data corresponding to an integrated luminosity of 94.5 pb
that were ...accumulated in an experiment with the SND detector at the VEPP-2000
collider. The cross section for this process was measured for the first time and was found to receive a dominant contribution from the mechanism of a transition through an
intermediate state. The cross section measured for the process
agrees with the results of earlier measurements in the channel
. At a level of 5.7 standard deviations (5.7
), it is established that the process
is not fully described by hadronic intermediate states of the
type. The cross section was measured for this missing contribution, which may be generated by radiative processes—for example,
. It ranges from 15 to 20 pb over a broad energy interval extending from 1.3 to 1.9 GeV.
The process
was studied in the energy range between 1 and 2 GeV to the best precision in the world. The data used correspond to an integrated luminosity of
accumulated with the SND detector at the ...VEPP-2000
collider. The statistical accuracy of the measured cross section is 2 to 22
, whereas the systematic uncertainty is 2.6 to 14
. The present results agree with the results of earlier measurements but have a better precision.
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