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The effect of an aqueous solution of NaCl salt on the change in the dissociation of Freon hydrate over time at atmospheric pressure was studied experimentally. In the experiments, an aqueous salt solution with an initial concentration of 3% was used. For Freon hydrate synthesized in a salt solution, in contrast to the hydrate synthesized in pure water: 1) the degree of gas conversion in gas hydrate is 1.36 times higher; 2) the dissociation rate is 1.26 times lower. The research carried out is important for the further development of technologies for the synthesis, desalination and storage of gas hydrates. [ABSTRACT FROM AUTHOR]

The effect of air velocity V in the channel on the dissociation of Freon R-134a hydrate at atmospheric pressure was studied experimentally. An increase in the velocity V led to an increase in the dissociation rate J, the surface temperature of the granules, and the temperature along the height of the Freon hydrate layer. An increase in velocity V from 0 to 2.5 m/s led to an increase in J by 2-2.1 times. [ABSTRACT FROM AUTHOR]

The boiling of a layer of an aqueous NaCl salt solution with different initial salt concentrations on an aluminum surface was experimentally studied. The rate of water evaporation for most of the boiling time is 1.6-1.7 times higher than for a salt solution with an initial mass concentration of 20%. An increase in the salt concentration in a solution during boiling leads to a decrease in the number of bubbles formed during boiling. The key factors influencing the boiling process and the cessation of boiling of salt solutions are considered. [ABSTRACT FROM AUTHOR]

The effect of an aqueous solution of NaCl salt with hydrogen peroxide on the corrosion of grade A steel 414 Grade A was experimentally studied. Long-term corrosive exposure on the surface of the substrate led to a change in roughness by 5.3-5.4 times. After placing a drop of solution on the substrate after 60 s, the area Sd of the drop increases 2.3-2.5 times. This change in Sd is associated with the formation of hydroxyl groups and a change in the roughness of the substrate surface due to corrosion. There are II modes for changing the area of the corrosion spot Sc. The change in dSc/dt for mode II (120 < t < 300 s) is 1.36 times higher than for mode I (t<120 s). [ABSTRACT FROM AUTHOR]

Experimental studies on the effect of aqueous salt solution on the corrosion of the aluminum alloy during droplet evaporation have been carried out. Corrosion on a smooth surface will increase the evaporation rate. The evaporation rate is constant on the textured wall after laser surface treatment. The minimum corrosive current corresponds to a hydrophobic textured surface. Laser texturing on the surface of the aluminum alloy helps resist corrosion. This textured alloy can be effectively used in the power industry when exposed to high-temperature corrosive environments. [ABSTRACT FROM AUTHOR]

When a drop of water evaporates on the surface of aluminum–magnesium alloy, the diameter of the drop is constant over time. When a drop of aqueous solution (H2O/NaCl/H2O2) evaporates, the diameter changes with time and depends on the wall textures. Corrosion on a smooth wall develops unevenly over the surface of the wetted drop spot. The onset of corrosion occurs at a distance from the contact line of the drop. The impact of laser radiation on the wall surface of the aluminum–magnesium alloy creates different textures that resist corrosion. This alloy with textures can be effectively used in the power industry when exposed to high–temperature aggressive media. [ABSTRACT FROM AUTHOR]

This work is devoted to an experimental study of the concentrations of gaseous emissions generated during the combustion of methane-isopropanol and methane-propane hydrates, as well as the dissociation rate at various temperatures in a muffle furnace. An increase in temperature from 700 to 1100 °C led to an increase in the rate of dissociation of double gas hydrates during combustion by 1.4–1.6 times. Increasing the temperature of the muffle furnace led to both a decrease in CO and H2 emissions and an increase in NOX and CO2 during the combustion of gas hydrates. The average concentrations of H2 and CO without combustion for methane-isopropanol is higher than for the methane-propane hydrate, and the average concentrations of NOX and CO2 differ depending on the temperature of the furnace. [ABSTRACT FROM AUTHOR]

This work is devoted to an experimental study of gaseous products formed during the combustion of methane-isopropanol hydrate powder at various temperatures in a muffle furnace. As the temperature in the muffle furnace increases, the fuel burns out faster due to the increase in the reaction rate, and NOX and CO2 emissions increase. With an increase in temperature from 700 to 1100 °C, the maximum concentrations of H2 and CO gases decreased by 5.5–5.8 times, while the maximum values of NOX and CO2 increased by 7–10 times. [ABSTRACT FROM AUTHOR]

Experimental study of the dissociation of Freon R-134a hydrate with an external air flow U0 was carried out. At U0 = 1.6 m/s, the non-uniformity of the temperature field increases on the powder surface. It is shown that the Freon hydrate dissociation rate decreases with time. The decrease in the dissociation rate is associated with a decrease in the free surface of the granules and the ingress of the powder into the region of self-preservation. The dissociation rate for U0 = 1.6 m/s is higher due to the increase in the heat transfer coefficient from the air flow. [ABSTRACT FROM AUTHOR]

The dissociation of Freon R-134a hydrate at atmospheric pressure was studied experimentally. Thermal imaging measurements showed that the minimum temperature of the powder surface corresponds to the center and the maximum near the sidewalls of the tank. Three characteristic regions of change in the dissociation rate (j) of Freon R-134a hydrate over time have been established. For the time 0 < t < 540 s, the dissociation rate has a maximum value (jI= 9.4·10-4g/s). For the time 540 < t < 1800 s, the dissociation rate decreases (jII=2.9·10−4g/s). For t > 1800 s, the minimum dissociation rate is observed (jIII=1.2·10−4g/s). [ABSTRACT FROM AUTHOR]

In this work, experimental studies on the dissociation of methane hydrate at different temperatures are carried out. During each individual experiment, the temperature was kept constant. In the area of self-preservation, the rate of dissociation of the gas hydrate decreases many times. The diffusion model of decay (based only on the diffusion coefficient) shows a significant excess of the calculation over the experiment in the region of self-preservation. [ABSTRACT FROM AUTHOR]

The combustion of methane hydrate over a layer of powder is experimentally investigated. When burning above the layer of powder, a laminar air flow is realized due to buoyancy. Air flow and high heat flux lead to a multiple increase in the rate of dissociation of methane hydrate. The outflow of gas from the powder layer is non-uniform and has a jet character. As a result, non-uniform combustion is realized, which reduces the stability of combustion. [ABSTRACT FROM AUTHOR]

An experimental study was performed on the effect of forced convection of heated air on the velocity inside a hanging drop of salt solution. It is shown that when modeling the convection velocity inside the droplet, it is necessary to take into account the determining key factors: forced air flow velocity U1 (dynamic factor); the thermal (thermal factor) and the solutal Marangoni numbers (MaT and MaC). The velocity component of the thermal factor can either exceed or be less than the velocity component of the dynamic factor. The convection velocity in the drop is proportional to the radius of the drop to the power of 0.5. Velocity in a drop of salt solution measured using the Particle Image Velocimetry method. [ABSTRACT FROM AUTHOR]

Experiments have been carried out to investigate convective motion in a stationary hanging droplet of water in an air flow. When modeling convective motion in a hanging drop, all key factors must be taken into account: air velocity; the thermal Marangoni flow (MaT), the solutal Marangoni flow (MaC), the Rayleigh number (Ra). The effect of air velocity on convection in a droplet decreases by a factor of 35–40 due to contamination on the free surface of the drop. The liquid velocity parameters were measured using the Particle Image Velocimetry method. The data obtained are of both scientific and practical interest. [ABSTRACT FROM AUTHOR]

An interaction of an incident drop on a sessile drop located on a hot wall was experimentally investigated. The behavior of convection with and without graphite particles was studied. Graphite particles lead to a decrease of mass transfer after droplet fall. The falling droplet caused a narrow temporal leap in speed into sessile drop. [ABSTRACT FROM AUTHOR]

Marangoni convection in a sessile drop of water on a heated wall was experimentally studied when a cold droplet fell on the hot surface. A comparison of the effect of an incident drop consisting of water and water with a volume concentration of 8% of the surfactant “AF 9-10” (Neonol) was made. The temperature of the falling drop was 24 °C and the wall temperature was 92 °C. The droplet fall of water led to an increase in the average drop velocity by 7-8 times. The use of surfactants led to a decrease in the jump in average speed by 1.7-1.8 times in comparison with liquid without surfactant. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of the synthesis of carbon dioxide gas hydrate by a method based on the explosive boiling up of a liquefied hydrate-forming gas in a volume of water during decompression. The experimental method is described and the ways of the process intensification are reflected. The effect of gas consumption during decompression on the synthesis of gas hydrate is shown. [ABSTRACT FROM AUTHOR]

In the paper presents experimental studies on the production of Freon 134a gas hydrate by a method based on the explosive boiling of a liquefied hydrate-forming gas in a volume of water during decompression. It is shown that in the method there is a simultaneous imposition of several factors leading to the intensification of the process of synthesis of gas hydrates, as a result of which a large amount of gas hydrate is formed in a short time. The ratio of the initial mass of gas to the initial mass of water per part of the gas transferred to the gas hydrate is presented. [ABSTRACT FROM AUTHOR]