The usage of coal-water fuel instead of dry coal for heat and power generation is a promising way to decrease harmful emissions during power generation. Improvement of the coal-water fuel ignition ...and combustion parameters is important due to the specifics of the fuel. The use of glycerol as a flammable additive to the coal-water fuel is environmentally friendly and leads to reducing the ignition time and threshold temperature of that composition fuel. Generally accepted approximation of the dependence of the main combustion parameters includes the ignition temperature and the time delay before ignition on the glycerol content of the fuel composition does not correspond to the physical nature of the process and does not reflect the real nature of the change. To approximate the experimental data in the case of complex two-component fuel based on the coal-water slurry and glycerol, a more suitable and physically correct inverse sigmoid function is proposed. The applicability of the proposed function has been confirmed by experimental studies.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Summary
For the fuel ignition, the thermal conductivity and heat capacity are the key properties that determine the pre‐ignition behavior of the drop of the fuel. The classic monophase fuels, such as ...natural gas, liquid propellants, or solid one‐component fuels, have been investigated for a long time; and their thermophysical properties are well known in most of the cases. Composite fuels, which have recently attracted the attention of the researchers, have complex contents. In many cases, composite fuel is a mixture of solid and liquid components in the form of a slurry. Coal‐water fuel and its derivatives with different additives are examples of such type fuels. For those fuels, the thermophysical properties are usually unknown. Nowadays, researchers use simple additivity theory for the calculation of the thermophysical properties of complex fuels for the first approach. Authors of this research believe that the simple additivity approach is not correct and can lead to the wrong results in the case of the numerical research of the ignition and burning processes of such a fuel. In the present research, the thermophysical properties of coal‐water fuel with glycerol additives were experimentally obtained. It was found that the coefficient of thermal conductivity increases with temperature and varies in the range of 0.45 to 0.53 W/(m·K). The heat capacity of the fuel also increases with the temperature and varies from 4.7 to 5.5 kJ/kg·K. The higher the glycerol content, the lower the thermal conductivity and heat capacity of the composite fuel in the investigated temperature range. The results confirm the failure of the approach of the additivity law usage. Neither, thermal conductivity coefficient or heat capacity of the coal‐water fuel with the addition of up to 20% glycerol complies with the additivity law. Differences between real values of the thermophysical properties and calculated ones are more than 30% to 50%. Empirical expressions for calculation of the thermophysical properties of coal‐water fuel with the addition of up to 20% glycerol are presented.
Glycerol affects thermophysical properties of the resulting suspension; thermophysical properties of CWF with glycerol do not obey law of additivity changes in thermophysical properties and can eliminate improvements in CWF combustion.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Coal-water fuel is a promising substitution of conventional fossil fuels for the countries, where clean energy sources like wind, solar, etc. cannot cover energy demand. However, this fuel has a lot ...of specifics for preparation, transportation, and combustion. Issues with coal-water fuel combustion can be solved with the use of fuel activation. The catalytic activation of the coal-water fuel produced from coal of different metamorphic stages with the help of titanium dioxide nanoparticles was experimentally studied. The research suggests that the addition of the titanium dioxide nanoparticles in 0.5–4% wt. increases the coal-water fuel thermal conductivity by 9–17% while the value of heat capacity decreases by 12–23%. Also, this addition decreases time delay before fuel ignition by 20–22% and a total time of the fuel droplet burning by 15%; increases maximum temperature of the volatiles combustion by 8–10%; and increases combustion completeness as well. For the first time, the optimal value of the nanoparticles additive content has been found.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
4.
The RED-100 experiment Akimov, D.Yu; Alexandrov, I.S.; Alyev, R.R. ...
Journal of instrumentation,
11/2022, Volume:
17, Issue:
11
Journal Article
Peer reviewed
Open access
Abstract
The RED-100 two-phase xenon emission detector has been
deployed at 19-m distance from the reactor core of the Kalinin
Nuclear Power Plant (KNPP) in 2021–2022 for investigation of the
...possibility to observe reactor antineutrinos using the effect of
coherent elastic neutrino-nucleus scattering (CE
ν
NS). The
performance of the main systems of the RED-100 setup at operating
nuclear power plant is described. There is no correlation of the
radioactive background at the experimental setup site with ON and
OFF states of the reactor. The data taking run was carried out at
the beginning of the year 2022 and covered both the reactor OFF and
ON periods.
Abstract
The RED-100 experiment with a liquid xenon target was
carried out at Kalinin Nuclear Power Plant. The goal of the
experiment is the detection and study of the coherent elastic
neutrino ...nucleus scattering process (CEνNS) for the low-energy
antineutrinos in close vicinity to a reactor core. A good
understanding of the external radioactive background is needed to
achieve this goal. This paper describes the external background
conditions for the RED-100 experiment at Kalinin Nuclear Power
Plant.
Using of coal-water slurries as fuel for heat and power generation is interesting for researchers for a long time. Coal-water fuel (CWF) application has two major aspects of investigation: ...rheological properties to provide its transportation and atomization; and improvement of fuel combustion parameters. CWF combustion characteristics improvement can be achieved with the help of different physical and chemical methods. Influence of electromagnetic field on the structure and properties of hydrocarbon fuels is known. However, influence of electromagnetic treatment on the combustion parameters of coal-water fuel produced from coal of different metamorphic stages was not investigated before.
Experimental investigations of coal-water fuel combustion parameters: ignition time, time-temperature correlations, ignition temperature, maximal temperature of flame and others were performed. Fuels produced from coal of 6 basic metamorphic stages, which cover a wide range from Brown coal to Anthracite, were used for research. Investigations were carried out in two cases: without fuel pre-treatment with an electromagnetic field, and with it. It is shown in the article that electromagnetic pre-treatment of coal-water fuel improves fuel ignition and combustion stability, increases combustion process efficiency and reduces the total time of fuel burning.
•Water-coal fuel (CWF) combustion process is investigated.•4 stages of the process are showed and analyzed.•Electromagnetic pre-combustion treatment combustion is proposed.•Electromagnetic pre-activation improves CWF combustion efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Despite all efforts, alternative energy sources cannot meet the growing energy demand of humanity at the moment; and coal keeps its position as an energy source. One the main problem of the ...coal-water fuel utilizing is to find the balance between its rheological properties, mainly its viscosity, which defines the efficient feeding and atomization of fuel, and combustion efficiency. Fuel viscosity is determined by the fraction of the water phase in fuel. On the other hand, water can influence negatively the combustion process. This paper describes the results of the experimental investigations on the influence of the water phase contents in the coal-water fuel on its combustion efficiency. It was found, that there is an optimal value of the water phase in the coal-water fuel. This optimal value is independent on general combustion parameters like the temperature of the oven medium and source coal metamorphic stage. It characterizes the rational combination of chemical and thermal processes involved in the fuel combustion. The results obtained are new and made a significant contribution to knowledge. They allow changing the viewpoint on the development of the methods for improvement of the utilizing of such type of fuel.
•Water phase in the coal-water fuel effects on fuel combustion in controversial manner.•Optimal water share was found in the range of traditional CWF formulations.•Optimal value is independent on coal grade and medium temperature of fire box.•The optimal water share allows getting the best CWF combustion parameters.•Using the optimal water share allows easy improving CWF combustion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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A combined passive shield of the RED-100 two-phase emission neutrino detector has been developed and built for suppressing the background of external γ rays and neutrons. The shield is composed of ...a 5‑cm-thick copper layer (the inner layer is adjacent to the detector) and a water layer with a total thickness of approximately 70 cm (including the water inside the copper shield). The Monte Carlo simulation of the shielding efficiency has been performed. The obtained attenuation factor of the copper shield for the γ-ray background has been experimentally verified in a laboratory test using a NaI(Tl) scintillator detector. The γ‑ray background rejection factor of the full shield has also been calculated.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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It is shown that the working volume of the RED-100 two-phase emission detector, which operates in a ground-based laboratory with liquid xenon used as a working substance, is a source of ...single-electron noise signals with a characteristic frequency of ~200 kHz. Possible mechanisms of generation of these noises and methods for their suppression are discussed.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper presents the results of the comparative research of combustion specifics of coal-water fuel produced from low-ash and high-ash Ukrainian flame coal. The analysis shows that the effect of ...the ash content in the coal-water fuel on the duration of the burning of a fuel drop depends on the drop size. The full combustion time of CWF drop based on the low-ash coal can be both less and longer than that of high-ash coal under the identical conditions for different equivalent diameters of the fuel drop. This specific is explained with the domination of different physical factors during the fuel combustion process.
The results of this research extend significantly our knowledge of coal-water fuel, allow understanding some issues of its combustion and are important for the design of the specialized energy facility which is used coal-water fuel as an energy source.
•Ash content in the coal-water fuel has an ambiguous effect on fuel combustion.•Burning time is the same for different ash content for a critical drop size.•Critical drop size depends on medium temperature of fire box.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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