Calculation of the Operation Parameters of the Catalytic Converters of the Harmful Gas Impurities

There are theoretically founded principles of catalytic converters designing of harmful gas emissions of various heat devices. Experimental investigations have shown that the smallest aerodynamic losses in the constructions of gas neutralizers are achieved at the using of profiled ceramic blades as working units - carriers of catalysts. To ensure intensive mixing of the flow inside the converter the input edges of the blades grids of the future stages should be located between the output edges of the blades of the grids of the preceding stages

PdO impact on the activity of hydrocarbon oxidation with oxide catalysts

The palladium component influence on the catalytic activity of a catalyst was investigated based on transition-metal oxides deposited on α-Al2O3 carrier in the process of hydrocarbon catalytic thermal destruction. It has been determined that the value of surface concentrations of PdO deposited on Co3O4 doesn’t effect on the achievable conversion degree when using the obtained catalytic converter. It is suggested that PdO facilitates the interfacial diffusion of atomic oxygen on the catalyst oxide component due to support it in an oxidized state. Adsorbed on palladium oxygen migrates on cobalt oxide in the composition of this catalyst. At the expense of this process oxygen passivation of Pd-Co3O4/γ-Al2O3 catalyst is overcome and its high reaction activity is ensured. Our research is evidence that Co3O4 performs the role of active centers on a corundum carrier in the reaction of catalytic thermal hydrocarbon oxidation. Additionally injected PdO into the catalyst composition promotes to the cobalt phase enrichment by oxygen

Determining Energy Cost for Milling Solid Matter in a Ball Mill

The article provides findings of analytical research into the process of milling friable matter in a ball mill. We have received an expression to determine energy cost of milling with the account of the method of milling and the characteristics of the material to be ground. In the paper, the analytical results of bulk materials grinding process in a ball mill are presented. The differential equation is obtained whose solution determines the value of the grinding mode coefficient, corresponding to the maximum value of grinding process efficiency. The use of the introduced ball mill modes allows reducing the time spent on grinding by 28.9 % for cement clinker, 18.4 % for black coal, 28.9 % for marble and 19.6 % for rock salt compared to the traditionally recommended ones

Electrodeposition of iron-molybdenum coatings from citrate electrolyte

Specifi c features of the electrodeposition of iron–molybdenum coatings from a citrate electrolyte based on iron(III) sulfate and sodium molybdate in dc and unipolar pulsed modes were studied. It was demonstrated that bright compact coatings with varied content of molybdenum can be produced by varying the relative concentrations of salts of the alloy-forming components and the solution pH. The current density ranges providing the high efficiency of the galvanostastic electrolysis were determined and it was shown that using the pulsed mode makes smaller the amount of nonmetallic impurities in a coating, diminishes its roughness and leads to formation of surface layers with a more uniform composition, The iron–molybdenum coatings exhibit a high corrosion resistance in corrosive media and physicomechanical properties improved as compared with the base metal, which makes it possible to recommend these coatings for protection from corrosive-mechanical disintegration and restoration of the surface of worn articles

The Longitudinal Flow of Oil and Petroleum Products in the Channels and Pipes. Part II

A model associated fluid flow and heat transfer of longitudinal flows of oil in pipes and channels is considered. The model is an extended version of the Bingham flow on the case of flow with one or two solid cores. The fluid part is a two-phase medium, wherein the disperse phase may consist of solid particles, droplets and gas bubbles. The sliding on the borders of pipes and channels, thermal conductivity and viscosity of such systems and their impact on the characteristics of the solid core are discussed. The flow with a yield point dependence on the temperature is also considered

Mixed alumina and cobalt containing plasma electrolytic oxide coatings

Principles of plasma electrolytic oxidation of the AL25 aluminum alloy in diphosphate alkali solutions containing cobalt(2+) cations are discussed. It has been established that a variation in the concentration of the electrolyte components provides the formation of mixed-oxide coatings consisting of the basic matrix materials and the cobalt oxides of different content. An increase in the cobalt oxide content in the coating is achieved by the variation in electrolysis current density as well as the treatment time due to both the electrochemical and thermo-chemical reactions at substrate surface and in spark region. Current density intervals that provide micro-globular surface formation and uniform cobalt distribution in the coating are determined. The composition and morphology of the surface causes high catalytic properties of synthesized materials, which confirmed the results of testing in model reaction CO and benzene oxidation as well as fuel combustion for various modes of engine operation

Формирование покрытий смешанными оксидами алюминия и марганца на сплаве АЛ25

Features of plasma electrolytic oxidation of the AL25 cast complex-alloyed aluminum alloy are discussed. It has been shown that a variation in the nature and concentration ratio of the electrolyte components provides the formation of mixed-oxide coatings containing the materials of the basic matrix and the dopant. An increase in the coating thickness and the manganese oxide content in the coating is achieved by the homogenization of the treated surface owing to the simultaneous formation of oxides and the removal of alloying components of the alloy from the surface layers. Current density intervals that provide a uniform distribution of elements in the coating and a high efficiency of the Faraday and thermochemical reactions are determined. It is found that the stoichiometric oxygen index in MnOx oxides is x = 1.71–1.87. Testing of the synthesized oxide systems in the model oxidation of carbon (II) oxide to CO₂ shows that the ignition and complete conversion temperatures are at the level of values characteristic of platinum catalysts.Рассмотрены особенности плазменно-электролитического оксидирования литейного сложнолегированного сплава алюминия АЛ25. Показано, что варьирование природы и соотношения концентраций компонентов электролита позволяет формировать покрытия смешанными оксидами, в состав которых входит материал основной матрицы и допанта. Повышение толщины покрытия и содержания в нем оксида марганца достигается гомогенизацией обрабатываемой поверхности за счет одновременного формирования оксидов и удаления легирующих компонентов сплава из поверхностных слоев. Установлены интервалы плотности тока, обеспечивающие равномерное распределение элементов в покрытии и высокую эффективность фарадеевских и термохимических реакций. Показано, что стехиометрический индекс по кислороду в оксидах MnOx составляет x = 1,71–1,87. Тестирование синтезированных оксидных систем в модельной реакции окисления оксида углерода (II) до CO₂ показало, что температура зажигания и полной конверсии находится на уровне платиновых катализаторов

Гальванохімічне формування багатокомпонентного сплаву на основі кобальта та тугоплавких металів

Effects of major parameters of electrolysis on the composition and morphology of the cobalt-molybdenum-tungsten alloy from citrate- pyrophosphate and citrate-ammonium electrolytes have been analysed. It has been shown that the content of component metals in the Co-W-Mo alloy depends on the nature and composition of the electrolyte solution. The influence of electrolysis conditions and regime on the structure and morphology of cobalt alloys with refractory metals has been established. The elemental composition and morphology of the triple cobalt - molybdenum - tungsten coatings have been determined with a scanning electron microscope.Проаналізовано вплив основних параметрів електролізу на склад та морфологію сплаву кобальт-молібден-вольфрам отриманого з цитратно-дифосфатного та цитратно-амоніачного електролітів. За допомогою сканівного електронного мікроскопу досліджено склад і морфологію потрійних покриттів. Було показано, що вміст компонентів в сплаві Со-W-Мо залежить від природи ліганда і співвідношення концентрацій сплавотвірних металів. Встановлено вплив густини струму, а також часу імпульсу та паузи на структуру і морфологію покриттів