N. G. Beregovtsova

Modification of iron ore catalysts for lignite hydrogenation and hydrocracking of coal-derived liquids

The activity of haematite, magnetite, pyrite and pyrrhotite containing ore catalysts, modified by treatment in a tensile-energy planetary activator mill and by elemental sulphur additions, has been studied in lignite hydrogenation and coal-derived liquid hydrocracking processes. The application of modified ore catalysts resulted in a significant (by two to four times) increasing of lignite conversion degree and in higher yields of distillate fractions, obtained by hydrocracking of heavy coal-liquids. Mechanical activation of iron ore catalysts in the presence of elemental sulphur increased their surface area and promoted the formation during hydrogenation process at dispersed pyrrhotite particles with high catalytic activity.

Lignin conversion in supercritical ethanol in the presence of solid acid catalysts

The effects of sulfated ZrO2 and ZrO2-Al2O3 catalysts and acidic zeolite catalysts with various Si/Al ratios on the thermal conversion of alkali lignin in supercritical ethanol at 300–400°C and on the composition of the resulting products have been investigated. All of the catalysts enhance lignin conversion into liquid products. The strongest effect with the catalysts based on sulfated ZrO2 is attained at 400°C; with the zeolites, at 350°C. The catalysts diminish the concentration of phenol and its derivatives and increase the concentration of ethers (mainly the 1,1-diethoxyethane concentration) in the liquid products. The zeolite catalysts are preferable, since the reaction over the ZrO2-containing catalysts produces gaseous compounds in higher yields. The maximum lignin conversion and a high yield of low-boiling liquid products are achieved at 350°C with the zeolite catalyst with Si/Al = 30, which contains a high concentration of acid sites that are stable at elevated temperatures. The most abundant phenolic liquid products of lignin conversion over the zeolite catalysts at 350°C are methoxyphenols and their methylated and ethylated derivatives.

Some features of chemical composition, structure and reactive ability of Kansk-Achinsk lignite modified by ozone treatment

Abstract The influence of ozonization of Kansk-Achinsk lignite on the chemical composition, structure and modified lignite reactivity in hydrogenation processes with different solvents (tetralin, coal derived liquid) and pyrite catalysts was studied. According to chemical analysis data the incorporation of oxygen into the organic matter of lignite takes place during ozonization. Some data indicating that ozonization results in loosening of the lignite structure were obtained by X-ray diffraction and e.p.r. techniques. Lignite modified by ozone treatment is more reactive, than untreated lignite, in hydrogenation reactions at 380°C–430°C in the presence of pyrite catalyst. For ozonized lignite the conversion degree was increased by 1.4 times in tetralin and 1.4–1.8 times in coal derived liquid in comparison with lignite previously treated in helium.

Conversion of coal into liquid products by hydrogenation and hydropyrolysis processes

The influence of highly dispersed iron-containing catalysts on the process characteristics of the hydrogenation (in tetralin) and hydropyrolysis of B2 brown coal and D and G black coals and the hydropyrolysis of brown coal and polyolefin mixtures was studied. The composition of the resulting liquid products was investigated by a GC-MS technique. It was shown that the use of catalysts significantly increased the degree of coal conversion and the yield of liquid products in all of the test processes. Maximum effects were observed in the presence of mechanochemically activated haematite, which was dispersed in tetralin by ultrasonication.

Developing Ways of Obtaining Quality Hydrolyzates Based on Integrating Catalytic Peroxide Delignification and the Acid Hydrolysis of Birch Wood

Traditional processes of acid-catalyzed hydrolysis of wood are ineffective due to the low quality of formed glucose solutions contaminated with impurities that inhibit fermentation of glucose to ethanol. This problem grows during the hydrolysis of birch wood containing large amounts of hemicellulose. This work proposes producing quality glucose solutions using sulfuric acid (H2SO4, 80%) catalyzed hydrolysis at 25°C the cellulosic products formed during the catalytic peroxide delignification of birch wood. It is established that the composition of cellulosic products strongly affects the contents of glucose, xylose, and impurities inhibiting the enzymatic synthesis of bioethanol: furfural, 5-hydroxymethyl furfural, and levulinic acid. High yields (80.4–83.5 wt %) of glucose are achieved using cellulosic products produced by integrating the processes of sulfuric acid hydrolysis of hemicelluloses from birch wood and peroxide delignification of prehydrolyzed wood in the presence of catalysts: 2% H2SO4 and 1% TiO2. Concentration of inhibitors of enzymatic processes in these hydrolyzates is below the allowable limits. Hydrolyzates with maximum glucose content (86.4–88.5 wt %) and minimum concentration of inhibiting impurities produced by acid hydrolysis of cellulosic products treated with an 18% solution of NaOH. Gas chromatography, HPLC, and chromato-mass spectrometry are used to analyze the composition of hydrolyzates. Cellulosic products are examined by SEM, XRD, and chemical analysis.

Studying the thermal conversion of acetone lignin in supercritical butanol in the presence of NiCuMo/SiO 2 catalysts

Existing and emerging technologies for the chemical processing of wood are mainly aimed at transforming its cellulose component into target products. In these processes, lignin is produced on a large scale as a waste product, but there are no advanced ways of processing it. This work investigates the effect NiCuМо/SiO2 catalysts have on the thermal transformation of acetone lignin in supercritical butanol at temperatures of 280, 300, and 350°C. The resulting liquid products are studied via gas–liquid chromatography mass spectrometry, and 13С NMR spectroscopy. It is found that butanol undergoes almost no thermochemical conversions at temperatures below 300°C. Catalysts raise its level of conversion to 36–40 wt %. Under the effect of NiCuМо/SiO2 catalysts, the yield of hexane-soluble products of acetone lignin thermal conversion at 300°C increases by a factor of 2.4, while the yield of solid residue falls by approximately a factor of 3.3. Catalysts reduce the relative content of methoxyphenols in hexane-soluble products: the content of syringol in particular falls by a factor of 14. According to 13С NMR spectroscopy, the catalytic transformation of acetone lignin to liquid acetone-soluble products is accompanied by the breaking of β–О–4 chemical bonds between the structural fragments of lignin and a reduction in the content of methoxyl groups, primarily in the syringyl structural units of the resulting products.

Effect of the ozonization of brown coal from the Kansk-Achinsk Basin on its pyrolysis in a mixture with polyethylene

It was found that the treatment of brown coal from the Kansk-Achinsk Basin with an ozone-oxygen mixture at 25–100°C for 1–8 h was accompanied by the formation of oxygen-containing structural groups in the organic matter of coal; the thermal stability of these groups was comparatively low. The preliminary ozonization of coal resulted in an increase in the degree of conversion and the yield of liquid distillation products in the course of coprocessing of coal with polyethylene.

Road asphalt modifiers based on oil-resistant rubbers and products of thermal transformations of coals

The properties of asphalt binder modifiers prepared by dissolving butadiene-acrylonitrile rubbers and their production waste in liquid products of heat treatment of various brands of coal were studied.

Influence of low temperature treatment on lignite structure and its liquefaction behavior

Publisher Summary This chapter discusses the influence of low-temperature treatment of Kansk–Achinsk lignite on its composition, structure, and reactivity for liquefaction. The elucidation of correlations between structural characteristics of coal and its reaction ability is very important problem in coal science. The structure of coal can be varied by its thermal treatment even at mild conditions. It is known the treatment of coal at 200°C changes the total concentration of oxygen and its relative content in different types of functional groups of coal. The most significant effects are observed for law-rank coals with high concentration of oxygen. Because coal-liquefaction processes are accompanied by the rupture of oxygen-containing bonds, the variation of these groups concentration changes the coal conversion degree.