Catalysts for steam conversion of carbon monoxide of the composition 44 wt

Studying the properties of nanomaterials is an important task, but nanomaterials with desired properties is a promising direction. The aim of this work is to investigate the influence of the value of the concentration of the modifier (ions Mn2+) on the structural and functional properties of modified aluminum oxyhydroxide. In this paper, using methods such as the X-ray diffraction studies, differential thermal analysis, electron microscopy, chromatography. The paper found that increasing the concentration of the modifier result in significant changes in the morphology, the appearance of metallic aluminum, which is well seen on X-ray data samples. The influence of thermal effects on a modified aluminum oxyhydroxide argon. Set the phase transition temperatures in the synthesized samples. It is shown that with increasing sodeozhaniya manganese in the composition of the synthesized samples decreases the value of specific surface area. Study of the functional properties showed that the synthesized material has catalytic properties in the oxidation of methane. It is shown that the effective sample is a sample with a manganese content of 2.7 wt. %. By XRD results calcined in air samples modified aluminum oxyhydroxide was shown that only in the sample with a manganese content of 2.7 wt. % MnAl2O4 phase is formed, which is catalytically active phase.

Using the method of combustion synthesis, a series of porous cermet materials from nickel and oxides (such as NiO, MgO, Al2O3, ZrO2, and rare-earth oxides) was synthesized. They investigated in terms of their application as catalysts of the reaction of oxidative coupling of methane into synthesis gas. It is found out that the composites containing about 50% (NiO + Ni) and a small amount (up to 5%) of Ce, La, Nd, and Pr-oxides at the temperature 830оС ensure the conversion efficiency of methane within 92 ÷ 95% and the H2/CO ratio 2.0 ÷ 2.1 in the reaction products. The data obtained suggest that the materials manufactured can be effectively used in the systems of syngas manufacturing (for the Fischer – Tropsch process) and in the production of hydrogen from natural gas.

Oxidative transformations of C1-C4 alkanes into olefins on oxide manganese catalysts were under study. We also studied oxidative coupling of methane (OCM) into ethylene on deposited and applied on the silicon dioxide catalysts. We studied the influence of chemical composition of catalyst and promotors on the OCM. Adding a little amount of ethane and propane hydrocarbons to methane allows increasing the concentration of ethylene in gases and significantly increasing productivity in ethylene. The study also shows the impact of the amount of manganese and promotors applied on SiO2 on the yield of olefins during the conversion of C3-C4 alkanes.

The influence of the concentration of Mn2+ in a solution for the hydrolysis of nanosized aluminum powder on the phase composition of the precursor and the content of manganese in samples of aluminum hydroxide is studied. Stages of the formation of catalysts from the precursors are studied by means of synchronic thermogravimetric (TG)-differential scanning calorimetry (DSC) analysis and X-ray phase analysis (XPA). The influence of the number of manganese ions in aluminum hydroxide on the phase composition and catalytic properties of MnO x -Al2O3 systems in the reaction of the deep oxidation of methane is also studied. It is shown that an increase in the concentration of manganese ions in the solution for hydrolysis raises the content of unreacted aluminum and X-ray amorphous hydroxides in the precursors of the catalysts. It is established that the phase composition of the catalyst and the catalytic activity in the reaction of the deep oxidation of methane depend on the content of manganese in the precursor.

The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the catalytic activity of the manganese-based system obtained depends on manganese amount and thermal activation conditions. It is approved that as the catalyst for deep oxidation of hydrocarbons the system with manganese content of 10.5 wt. % is the most perspective despite the fact that the oxidation rate of methane is lower in it than in the catalyst with Mn content of 5.7 wt. %. As opposed to the catalyst with Mn content of 5.7 wt. %., where the aluminium oxide is in metastable form (s-Al 2 O 3 ), the catalyst with manganese content of 10.5 wt. % contains in its structure a thermodynamically and thermally stable α-Al 2 O 3 phase.

The effect of a promoter on the acidic and catalytic properties of aluminum oxide in the reaction of acetic acid ammonolysis has been studied. It has been shown that the promotion of γ-Al 2 O 3 with phosphorus-oxygen compounds results in a change in the porous structure, an increase in the concentration of acid sites, and site strength redistribution, thereby enhancing the activity and selectivity of the catalyst. The change in the acid properties of γ-Al 2 O 3 surface has a significant effect on the second stage of the process, the dehydration of acetamide.

The influence of principal parameters (reaction temperature, ratio of acetic acid and ammonia, composition of reactionary mixture and promotion of catalysts) on the selectivity and yield of the desired product was studied in the reaction of catalytic acetonitrile synthesis by ammonolysis of acetic acid. The processing of γ-Al2O3 by phosphoric acid increases amount of the centers, on which carries out reaction of acetamide dehydration. The kinetic model of a limiting stage of reaction – the acetamide dehydration to acetonitrile was suggested. In the process of ammonolysis of acetic acid it was demonstrated that the use of catalysts promoted by phosphoric acid and ratio NH3:CH3COOH=(3-4):1 at temperatures of a reactor 360-390°С leads to the increase of acetonitrile productivity to 0.7-0.8g/cm3·h and allows to minimize formation of by-products.

Catalysts containing 15 wt % Ni on MgО-Cr 2 О 3 supports with different ratios of magnesium and chromium oxides were prepared. The catalysts were tested in the reactions of partial oxidation and of carbon dioxide and combined reforming of methane into syngas. The phase composition of the catalysts was studied by X-ray diffraction analysis, and the concentration of base sites on the catalyst surface was determined by temperature-programmed CO 2 desorption. The 15 wt % Ni/MgО·Cr 2 O 3 catalyst ensures the highest output of syngas in combined reforming of methane.

Al 2O 3, что позволяет стабильно работать данному катализатору во всем температурном диапазоне реакции окисления С 1-С 3 углеводородов.The study of influence of manganese (II) amount in a precursor of MnO х/Al 2O 3 catalysts for hydrocarbon deep oxidation is perspective for technologies of catalysts. The main aim of the study is to investigate the influence of Mn (II) amount in nanofibrous aluminum oxyhydroxide a precursor of MnO х/Al 2O 3 catalysts on phase structure and regularities in deep oxidation of C 1-C 3-alkanes. The methods used in the study: chromatography, X-ray analysis. The results: The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the modified catalyst as full aluminum oxyhydroxide can work only in preliminary thermal activation at 850 °C. The paper demonstrates that the catalysts with 10,5 mas. % Mn (II) is more perspective as the catalyst of hydrocarbon deep oxidation in spite of the fact that methane oxidation speed on it is lower, than on the catalyst with 5,7 mas. % Mn (II). In comparison with the catalyst with 5,7 mas. % Mn (II) where aluminum oxide is in metastable form (σ-Al 2O 3) the catalyst with 10,5 mas. % Mn (II) contains in the structure thermodynamically and thermally stable phase αAl 2O 3, that allows this catalyst to work over the entire temperature range of C 1-C 3 hydrocarbon oxidation.

Aluminum oxyhydroxide nanofibers modified by manganese ions (II) was shown to have catalytic properties in a reaction of methane deep oxidation. It was established that the catalytic activity was increased at heating the samples in air at 850 degrees C, which is associated with the formation of the manganese oxide phases on the surface of aluminum oxide. The most promising catalyst for the high-temperature combustion of methane was found to be the system with manganese content in a catalyst of 5.7 wt. %.

The effect the method of preparation has on the formation, phase composition, porous structure, and catalytic properties of the 10% Ni-ZrO2 system during the partial oxidation of methane into syngas is studied. Stages of the formation of catalysts from precursors and the effect the method of preparation has on the phase composition, particle size, and catalytic properties of the active component during the partial oxidation of methane into syngas are investigated by means of synchronous TG-DTG/DSC and X-ray diffraction. The synthesis of a catalyst precursor via coprecipitation is shown to yield a monophase system with high nickel dispersion, catalytic activity, and stability.

Catalysts containing 15 wt % Ni on MgO-Cr2O3 supports with different ratios of magnesium and chromium oxides were prepared. The catalysts were tested in the reactions of partial oxidation and of carbon dioxide and combined reforming of methane into syngas. The phase composition of the catalysts was studied by X-ray diffraction analysis, and the concentration of base sites on the catalyst surface was determined by temperature-programmed CO2 desorption. The 15 wt % Ni/MgO·Cr2O3 catalyst ensures the highest output of syngas in combined reforming of methane.

Исследовано влияние способа приготовления на формирование, фазовый состав, пористую структуру и каталитические свойства 10% Ni/ZrO2-системы в реакции парциального окисления метана в синтез-газ. Методами синхронного ТГ-ДТГ/ДСК и РФА изучены этапы формирования катализаторов из прекурсоров, влияние способа приготовления на фазовый состав, размер частиц активного компонента и каталитические свойства в реакции парциального окисления метана. Показано, что синтез прекурсора катализатора методом соосаждения позволяет получить монофазную систему с высокой дисперсностью никеля и высокой каталитической активностью и стабильностью.

This paper describes the plasma-assisted combustion system intended to generate a torch flame with a high power density per unit area. In the system, a kind of hybrid concept is proposed. A primary unit for combustion sustaining is a low-current nonsteady-state plasmatron with a low level of electric power. The plasmatron activates an air/hydrocarbon mixture and sustains the oxidation processes in the plasma torch. In turn, the heat power of the torch sustains the main burning process in the torch flame. The results of experiments on propane oxidation in the plasma torch of plasmatron in a wide range of equivalence ratio are presented. As applied to the combustion system design, the plasma torch can provide both the complete and the partial propane oxidation with syngas generation.

Effect of a microwave field on metallic catalysts was studied in the reaction of decomposition of methane into hydrogen and highly dispersed carbon. The dependence of the conversion of methane, yield of carbon, and its composition on the chemical nature of a catalysts and reaction conditions was examined.

The experimental results of investigation of the natural gas conversion (СН4 ≈ 95%) to the nanocarbonic material (NCM) and hydrogen in the microwave discharge plasma of atmospheric pressure in the microwave plasmachemical reactor are presented. The reactor peculiarity providing its continuous operation is the available auxiliary discharge system in the reactor for initiation and maintenance of the primary microwave discharge. The dependence of the conversion level on the energy input, consumption and composition of the plasma-forming gas has been investigated. The increase (up to 70%) in the gas conversion level is shown in comparison with the process of the hightemperature pyrolysis. The experimental results on the energy efficiency of the plasmachemical process, composition and characteristics of the obtained NCM are given.

In the reaction of deep oxidation of СО and C4-10 oxide applied catalysts of perovskite structure are examined. Activity of platinum-containing catalyst and oxide systems in deep oxidation are compared. The conclusion is made on the fact that catalyst system containing superstoichiometric manganese is the most appropriate one for using in thermal generators.