The formation of zirconia-based isomerization catalysts during thermal conversions of hydroxide modified with different amounts of tungstate groups has been studied by differential scanning calorimetry and X-ray diffraction analysis. The mechanism of formation of tungstated zirconia from a hydroxide precursor has been formulated.

The process of thermal dissolution of medium metamorphosed coals in anthracene oil to produce an alternative pitch binder was studied. The process was carried out at temperatures from 350 to 400°C and pressure not higher than 2.5 MPa, without the use of hydrogen and catalysts. It was determined that during thermal dissolution hard coal of gaseous-fat grade demonstrated a higher activity compared with less metamorphosed gaseous coal. Under optimal conditions at a temperature of 350-380°C yields of pitch tar containing product are 63-75%. With regard to their composition and the main technical characteristics the isolated pitches are at the level in the middle between the coal-tar and oil pitches. Based on the yield data analysis, technical and environmental characteristics of the isolated pitch products a conclusion was made on the prospects of thermal dissolution process as an alternative method for preparing extractive pitch- a substitute for coal-tar pitch produced by coking process.

The conversion of brown coals and sapropelic coal in toluene containing mixtures with co-solvents (water, ethanol and tetralin) was studied under sub- and supercritical conditions within the temperature range of 375-550°C and at pressures from 7 to 40 MPa. It was found that the extent of coal extraction in the toluene solvent medium, at 400°C, was significantly increased by the addition of small amounts of hydrogen-donor tetralin or ethanol co-solvents. The extract yield from sapropelic coal reached 79-83%, with the gas yield being small. The effect of process variables on extract yields under sub- and supercritical conditions was monitored. Coal extraction in the toluene-tetralin mixtures was found to depend mainly on the hydrogen donor ability of the tetralin co-solvent irrespective of sub-or supercritical toluene states. According to the composition, the bitumen extracted from coals can be used as a feedstock for pitch production. In the water containing mediums, aside from coal liquefaction, coal methanation, hydrolysis and oxidation reactions occurred resulting in the generation of large amounts of methane, hydrogen and carbon dioxide.

Представлены результаты исследования каталитических свойств платиносодержащего диоксида циркония, модифицированного вольфраматными группами, в реакции гидроизомеризации н-гептана и смеси н-гептана с бензолом. Показано, что на синтезированных катализаторах изомеризация н-гептана эффективно осуществляется в присутствии бензола при температурах 200–225°C. Установлены причины снижения каталитической активности Pt/WO /ZrO2 при повышенных температурах реакции (250–280°C). Методом ДСК исследованы отработанные катализаторы. Показано, что с увеличением температуры реакции гидроизомеризации возрастает количество коксовых отложений на поверхности катализатора и их устойчивость к выгоранию при регенерации.

The results on investigation of the catalytic properties of platinum-containing, tungstate-modified zirconium dioxide in the hydroisomerization reaction of n -heptane or a n -heptane-benzene mixture have been presented. It has been shown that n -heptane isomerization on the catalysts synthesized was effective in the presence of benzene at 200–225°C. It has been found that the catalytic activity of the Pt/WO 4 2− /ZrO 2 catalyst decreases with increasing reaction temperature (250–280°C). The catalysts have been examined by the DSC method. It has been shown that the amount of coke deposed on the catalyst surface increases and its resistance to burning in regeneration is enhanced with an increase in the hydroisomerization reaction temperature.

The effect of preliminary mechanical activation in the energy-intensive mill-activator on the structural and chemical transformations of brown coals and their reactivity in contact with solvents has been established. Mechanical treatment of the brown coals from Kansk-Achinsk Basin was performed in a high-energy AGO-2 centrifugal planetary ball mill. Mechanical activation led to a partial destruction of the supramolecular structure of coal, reduction of the crosslinking degree of nano-sized polyaromatic clusters in the organic matter coal. This results in the increased reactivity of coal in the liquefaction processes (extraction and hydrogenation) to form liquid products.

Изучено влияние вольфрамат- и молибдат-анионов на формирование фаз диоксида циркония из аморфного анионмодифицированного гидроксида при механохимическом воздействии. Показаны важные отличия в действии анионных добавок при формировании метастабильной модификации диоксида циркония из аморфного гидроксида в процессе его механохимического превращения в сравнении с термохимическим процессом. В термическом процессе добавки анионов способствуют формированию и стабилизации нанокристаллической тетрагональной модификации диоксида циркония. В процессе механохимического синтеза анионные добавки, напротив, ингибируют образование метастабильной фазы.

We have studied the effect of tungstate and molybdate anions on the formation of zirconia polymorphs from amorphous anion-modified zirconium hydroxide during mechanochemical processing. The results demonstrate that the effect of anion additives on the formation of metastable zirconia from amorphous zirconium hydroxide during mechanochemical processing differs in a number of important points from that in thermochemical processes. In thermal processes, anion additives favor the formation and stabilization of nanocrystalline tetragonal zirconia. By contrast, in mechanochemical synthesis, anion additions inhibit the formation of metastable zirconia.

The texture, phase and surface composition and acidity of impregnated and precipitated Pt/WO4 2−/ZrO2 catalysts have been investigated with XRD, XPS, FTIR spectroscopy, and BET measurements. It has been shown that increasing the tungstate ion concentration in hydrated zirconium oxide results in an increase in the t-ZrO2 fraction in the catalysts following high temperature activation. While a fraction of W6+ and W5+ cations forms a solid solution with zirconia, the remaining W ions are stabilized on the catalysts surface as (–WOx–)n clusters. The catalytic activity in n-heptane isomerization seems to correlate with catalyst surface acidity to reach the greatest value at the WO4 2− concentration in the range of 12.9–17.6 mol %.

Исследованы физико-химические и технические свойства частично отработанного катализатора риформинга R-98 на установке ЛК-6Ус на Ачинском НПЗ, изменения этих характеристик в ходе эксплуатации после четырех циклов регенерации. Установлено, что в процессе эксплуатации катализатора происходило уменьшение величины его удельной поверхности, частичное фазовое превращение оксидного носителя, накопление углеродистых отложений и примесей металлов, являющихся каталитическими ядами. При проведении регенерации не достигалось полного восстановления свойств. В совокупности отмеченные необратимые изменения характеристик катализатора приводили к постепенному снижению его эффективности в процессе риформинга.

The physicochemical and technical properties of the R-98 reforming catalyst partially spent on a LK-6Us unit in the Achinsk refinery and changes in these characteristics during operation after four regeneration cycles have been studied. It has been found that during the time on stream of the catalyst, a reduction in the specific surface area, partial phase transformation of the oxide support, and buildup of carbon deposits and metal impurities serving as catalyst poisons take place. The regeneration did not afford complete recovery of the properties. In total, the above irreversible changes in the catalyst characteristics led to gradual degradation of the efficiency upon reforming.

The effect of manganese and aluminum cations on the formation of the crystalline structure and catalytic properties of tungstated zirconia has been studied. It has been shown that the modification of ZrO2 with both cationic and anionic additives leads to the stabilization of its tetragonal form and the formation of substitutional solid solutions on its basis. It has been found that manganese and aluminum additives have different effects on catalytic properties in heptane isomerization.

Изучено влияние катионов марганца и алюминия на формирование кристаллической структуры и каталитические свойства вольфрамированного диоксида циркония. Показано, что модифицирование ZrO2 как катионными, так и анионными добавками приводит к стабилизации его тетрагональной формы и формированию на ее основе твердых растворов замещения. Установлено различное влияние добавок марганца и алюминия на каталитические свойства в реакции изомеризации гептана.

С применением физико-химических методов исследования (рентгенофазового анализа, рентгенофотоэлектронной и ИК-спектроскопии) установлено, что при различных способах введения в гидроксидный предшественник вольфрамат-анионов в количестве более 13 мол. % при термической обработке (600–700°С) формируется метастабильная фаза диоксида циркония тетрагональной модификации. Показано, что катионы W6+ и W5+ образуют твердый раствор с ZrO2. Установлено, что на поверхности твердого раствора катионы вольфрама образуют вольфраматные кластеры (-WОx-)n. Сделан вывод, что образование фазы WO3 наблюдается при повышении концентрации вольфрамат-анионов более 17.6 мол. % или температуры до 850–870°С

The formation of the crystalline structure and textural properties of zirconia during the thermal activation of a hydroxide precursor with additives of tungstate anions at temperatures of 600–870°C has been studied. It has been found that, in the application of the different methods of mixing (coprecipitation or impregnation) of tungstate anions and zirconium hydroxide in the amount of more than 12.9 mol %, a dispersed phase of tetragonal zirconia having a mesoporous structure with a pore size of 7–8 nm is formed during thermal treatment. The catalytic activity of Pt/WO 4 2− /ZrO 2 in the isomerization of n -hexane and n -heptane depends in a nonmonotonic mode on the concentration of tungstate anions. In both reactions at a low temperature, high yields of isomers with a selectivity of at least 87% are achieved on the catalyst that has been prepared by impregnation and contains 17.6 mol % WO 4 2− .