Thermocatalytic conversion of petroleum paraffin in the presence of tungsten carbide powders

Russia occupies the third place in the world in terms of stocks of heavy oil raw materials. The development of deposits of light and medium oils makes it inevitable to involve heavy, as well as residual, petroleum raw materials in processing to meet the growing demand for petroleum products. Increase of the depth of oil processing possible in various ways, one of which is the use of new efficient catalysts, resistant to corrosion, poisoning and coking. Tungsten carbide, meeting these requirements, is a promising starting compound for the production of cracking catalysts for heavy oil feedstocks. The influence of tungsten carbide and its calcination temperature on the composition and yield of oil paraffin cracking products on the resulting catalysts was studied to investigate its catalytic activity, the optimum treatment temperature of tungsten carbide was determined. The high catalytic activity of a WC sample calcined at 420°C is shown. Using the physicochemical methods of investigation, the properties of tungsten carbide samples, as well as the composition and properties of the paraffin cracking products in the presence of the catalysts obtained, were studied

Investigation of Massive Catalyst based on Molybdenum Disulphide by Simultaneous Thermal Analysis and Mass Spectrometry Methods

The paper presents the results of experimental studies of massive sulfide catalysts by simultaneous thermal analysis and mass spectrometry. It is found that the STA/MS methods are quite informative for testing the catalyst systems based on MoS2 and are useful in identification of the reference features that could be used to predict their activity. It is also shown that the defect structure of molybdenum disulfide formed during mechanical activation is reflected on the DSC curves

Generation of Liquid Products from Natural Gas over Zeolite Catalysts

The main component of the natural gas is methane, whose molecules are characterized by a high chemical and thermal stability. It is impossible to perform the chemical transformation of natural gas into liquid organic compounds without applying highly active polyfunctional catalysts. Natural gas might be converted into liquid products in the presence of zeolite catalysts of pentasil family. Zeolite catalysts of ZSM-5 type were prepared to realize the process. They contained various amounts of Zn and Ga promoters introduced by ion exchange and impregnation. It has been shown that in the presence of small amounts of C2-C5 alkanes in the feedstock the methane is converted into aromatic hydrocarbons much more readily and in softer conditions than pure methane. At optimum process conditions reached is a high conversion of the natural gas into a mixture of aromatic hydrocarbons. This mixture mainly consists of benzene and naphthalene and small amounts of their derivatives – toluene, C8 and C9+ alkylbenzenes, methyl- and dimethylnaphthalenes. An optimum composition of zeolite matrix and the amount of the modifier in the catalyst have been established

Механохимическое модифицирование оловянных бронз интерметаллидом Cu9 Al4

The influence of the conditions of mechanical activation of a mixture of Cu–12 wt. % Sn with different content of the modifier Cu9 Al4 on the structural-phase composition and morphology of the formed composites was studied by the methods of X-ray diffraction analysis, optical and electron microscopy. With the mechanochemical introduction of 10 wt. % of the modifying additive into the matrix of mechanosynthesized tin bronze, the product mainly forms a ternary solid solution of aluminum and tin in copper, Al0.05Cu0.9Sn0.05. In the case of 20 wt. % of the modifying additive, the product contains a solid solution of tin in copper Cu0.9Sn0.1 and an intermetallic compound Cu9 Al4. Studies of the mechanical and tribotechnical characteristics of the material obtained by sintering under pressure showed that the intensity of wear of bronze of the mechanochemically synthesized powder Cu–12 wt. % Sn is slightly less than that of industrial bronze BrTPh10-1, the friction coefficient f decreases by a factor of 1.4, and the range of its values is quite wide f = 0.7–0.9. Modification of mechanically synthesized Cu–12 wt. % Sn bronze with the Cu9 Al4 intermetallic compound makes it possible to reduce wear by a factor of 1.4–1.8 and significantly reduces the friction coefficient (by a factor of 2). A stable value of f = 0.5 is achieved for the MA composition Cu–12 wt. % Sn + 20 wt. % Cu9 Al4. The introduction of an intermetallic compound increases the microhardness of the alloys by a factor of 1.6–2.0 (up to Hμ = 2730 MPa) relative to the bronze alloy BrTPh10-1and mechanically synthesized bronze.Методами рентгеноструктурного анализа, оптической и электронной микроскопии изучено влияние условий механической активации смеси Cu–12 мас. % Sn с различным содержанием модификатора Cu9 Al4 на структурно-фазовый состав и морфологию формируемых композитов. При механохимическом введении 10 мас. %-ной модифицирующей добавки в матрицу механосинтезированной оловянной бронзы в продукте формируется в основном тройной твердый раствор алюминия и олова в меди, Al0,05Cu0,9Sn0,05. В случае 20 мас. %-ной модифицирующей добавки в продукте присутствуют твердый раствор олова в меди Cu0,9Sn0,1 и интерметаллид Cu9 Al4. Исследования механических и триботехнических характеристик материала, получаемого методом спекания под давлением, показали, что интенсивность изнашивания механохимически синтезированного порошка Cu–12 мас. % Sn незначительно меньше, чем у промышленной бронзы БрОФ 10-1, коэффициент трения f снижается в 1,4 раза, а диапазон разброса его значений достаточно широк f = 0,7–0,9. Модифицирование механосинтезированной бронзы Cu–12 мас. % Sn интерметаллидом Cu9 Al4 позволяет снизить изнашиваемость в 1,4–1,8 раза и значительно снизить коэффициент трения (в 2 раза). Cтабильное значение f = 0,5 достигается для механической активации состава Cu–12 мас. % Sn + + 20 мас. % Cu9 Al4. Введение интерметаллида повышает микротвердость сплавов в 1,6–2,0 раза (до Hμ = 2730 МПа) относительно сплава бронзы БрОФ 10-1 и механосинтезированной бронзы

Механически стимулированные реакции в системах металл–оксид (карбид)

The processes of mechanochemical reduction of oxides of iron, nickel, and copper with aluminum with a stoichio metric ratio of components and in mixtures with a two-, three-, and four-fold excess of the aluminum content over the stoichiometric, as well as in the presence of an excess of oxide-forming metal and solid solutions of aluminum in iron and copper, were studied by the Mössbauer and IR spectroscopy, X-ray diffraction analysis, including the use of synchrotron radiation, and electron microscopy. The conditions for formation of metals modified with aluminum oxide (iron, nickel, copper) and their monoaluminides are determined. High aluminum content aluminides are formed at a three-fold excess of aluminum, and at a four-fold excess, a mechanochemical reduction of oxides does not occur. The preferred method for modifying metals with alumina is the mechanochemical reduction of oxides with a solid solution of aluminum in the oxideforming metal. Mechanochemical interaction in the high-energy Hf–C system in the presence of 20, 30, and 50 wt. % copper leads to the formation of hafnium carbide; and with an increase in the copper content, the crystallite size decreases.Методами мессбауэровской и ИК-спектроскопии, рентгеноструктурного анализа, в том числе с использованием синхротронного излучения, и электронной микроскопии изучены процессы механохимического восстановления оксидов железа, никеля и меди алюминием при стехиометрическом соотношении компонентов и в смесях с двух-, трех- и четырехкратным превышением содержания алюминия над стехиометрическим, а также в присутствии избытка оксидобразующего металла и твердых растворов алюминия в железе и меди. Определены условия, при которых могут быть получены металлы (железо, никель, медь) и их моноалюминиды, модифицированные оксидом алюминия. При трехкратном избытке алюминия формируются алюминиды с большим содержанием алюминия. При четырехкратном увеличении содержания алюминия механохимическое восстановление оксидов не происходит. Предпочтительным способом модифицирования металлов оксидом алюминия является механохимическое восстановление оксидов твердым раствором алюминия в металле, образующем оксид. Методами рентгеновской дифракции и электронной микроскопии изучено механохимическое взаимодействие в высокоэнергетической системе Hf–C в присутствии 20, 30 и 50 мас. % меди. Показано, что с увеличением содержания меди в системе Hf–C–Cu уменьшается размер кристаллитов образующегося карбида гафния

Investigation of the Properties of Mo/ZSM-5 Catalysts Based on Zeolites with Microporous and Micro–Mesoporous Structures

The dehydroaromatization of methane (MDA) is of great interest as a promising process for processing natural and associated petroleum gases, the main component of which is methane. The rapid loss of catalyst activity because of coke formation hinders the introduction of the DHA methane process into the industry. Therefore, the aim of this research was to find ways to improve Mo/ZSM-5 catalysts for MDA. The paper presents the results of the synthesis of high-silica zeolites of the ZSM-5 type with microporous and micro–mesoporous structures, the preparation of Mo/ZSM-5 catalysts based on them, and the study of the physicochemical and catalytic properties of the obtained samples during the non-oxidative conversion of methane into aromatic hydrocarbons. Zeolite catalysts were investigated using IR spectroscopy, X-ray diffraction, TPD-NH3, SEM, HR-TEM, and N2 adsorption. It was found that the addition of carbon black in the stage of the synthesis of zeolite type ZSM-5 did not lead to structural changes, and the obtained samples had a crystallinity degree equal to 100%. The creation of the micro–mesoporous structure in Mo/ZSM-5 catalysts led to an increase in their activity and stability in the process of methane dehydroaromatization. The highest conversion of methane was observed on a 4.0%Mo/ZSM-5 catalyst prepared based on zeolite synthesized using 1.0% carbon black and was 13.0% after 20 min of reaction, while the benzene yield reached 7.0%. It was shown using HR-TEM that a more uniform distribution of the active metal component was observed in a zeolite catalyst with a micro–mesoporous structure than in a microporous zeolite