I. RENEWABLE ENERGY. 2. Wind energy
Hydrogen Economy
The paper investigates the partial oxidation of ethanol process in a quartz microreactor at atmospheric pressure in the temperature range 300–450 °C on a nickel catalyst (20 wt%) deposited on zinc oxide. Rectified ethanol (an azeotropic mixture of 95.6 wt.% ethanol and 4.4 wt.% water) is fed into the reactor at a rate of 0.4–1.3 g / hour by a peristaltic pump, first into the evaporator, and then as a gas phase into the reactor. Air is used as a source of oxygen which is supplied by an air pump to the reactor and its flow is controlled by a rotameter so that the oxygen-ethanol molar ratio varied between 0.45 and 2.0. The nickel catalyst is prepared by impregnating industrial zinc oxide powder with nickel nitrate, followed by calcination and reduction of nickel oxide to metallic nickel. Analysis of gaseous products is performed on a Tsvet-500 gas chromatograph. The detector is a katharometer.
A catalyst Ni/ZnO developed earlier is shown to have high efficiency in the partial oxidation of ethanol at low temperatures. The main products of this process are hydrogen, methane, carbon monoxide and dioxide. With an increase in the oxygen-ethanol molar ratio, the hydrogen content in the products of the process decreases (from 60 to 25 vol.%), carbon dioxide, on the contrary, increases (26 to 65 vol.%). The hydrogen yield is 1 mol per 1 mol of ethanol at a temperature of 450 °C.
Carbon monoxide is observed with a low ratio of oxygen-ethanol (up to 0.85). With a higher ratio, carbon monoxide is absent in the entire temperature range studied. The conversion of ethanol proceeds intensively and already at a temperature of 450 °C ethanol is converted almost completely. A high methane content (20–30% vol.%) in reforming products indicates that the initial stage of the process is the oxidation of ethanol followed by decomposition of the resulting acetaldehyde into methane and carbon monoxide.
The insignificant water content in the supply mixture leads to an almost complete absence of a shift reaction. Carbon monoxide is then oxidized with oxygen to carbon dioxide. The reduced methane content in comparison with the process of water-steam ethanol reforming can be explained by its partial oxidation to carbon dioxide, which explains the high content of the latter in reforming products.
VII. ENVIRONMENTAL ASPECTS OF ENERGY.17. Energy and Ecology
The article describes the formation of dissipative structures in a liquid in a metal bowl when exposed to lowfrequency sound vibrations. The fluctuating volumes in a thick layer of liquid, that is, clusters of molecules, which make an oscillatory motion and with a loss of stability occupying a new position in the liquid, are investigated. An external synchronous effect on a group of molecules can lead to increasing oscillations and loss of stability not only inside the liquid, but these groups of molecules can leave the liquid through the free surface.
Friction on the outer surface of a bowl made of a conductive bronze-containing alloy, which initiates the occurrence of sound vibrations, gives rise to the appearance of new structures in the fluid inside the bowl. The thickness of the liquid layer is about 50 mm. The coordinated addition of energy to the oscillating microvolumes of water allows them to release their potential energy and turn it into kinetic. Water droplets ejected vertically indicate the existence of intense vertical movement of individual volumes of fluid which create new structures and cells, like Benard cells, resulting from heating and vertical convection, but smaller sizes. The observed phenomenon is similar to “cold boiling”. Here, probably, the potential energy of the compressed water particles is released under the influence of external sound vibrations. Sound analysis was performed using an audio editor for several experiments of various lengths.
In this work, the dissipative effect in a thick layer of liquid when exposed to low-frequency sound vibrations and the appearance of structures identical to Benard cells in limited volumes of water (and not in a thin layer) is first investigated. It should be assumed that the effect of sound vibrations can lead to blood turbulization and a change in the physical state of living organisms, which in terms of physical effect can be similar to the state of blood boiling with a rapid rise from the depth of the sea. The phenomenon can be used for the intensification of heat and mass transfer in heat exchange installations.