Study on Hydrogenation Performance of Oil-Soluble Molybdenum Catalyst in Coal-Oil Co-Processing

An oil-soluble molybdenum catalyst was synthesized by a simple and novel method and studied for hydrogenation in coal-oil co-processing. The catalyst was characterized by infrared spectrum (IR), thermogravimetry (TG), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The morphology and crystal structure of catalyst was characterized with scanning electron microscope (SEM) and high resolution transmission electron microscopy (HRTEM). The catalyst can be considered as a precursor that can be converted into active MoS2 components through thermal decomposition and sulfidation. The hydrogenation experiment was carried out by the model reactants of tetradecane and 2-methylnaphthalene with a change of reaction (405℃-445℃) temperature and concentrations of molybdenum catalyst (Mo conc. 0.6-10 mg/g), and results showed that the delightly hydrogenation function of catalyst is to improve the saturation of aromatic ring. The most abundant stacking numbers of decomposed catalyst were 2 and 3, accounting for 53% of all catalyst microcrystalline units. The rapid hydrogenation stage and the significant decrease of feed heavy fraction in co-processing experiment provided the evidence that the hydrogenation performance of the synthesized catalyst is remarkable in coal-oil co-processing.

Investigation of the process of extraction of a highly starchy fraction of rye flour by air classification

The article provides an overview of the current state of the application of solid-phase methods for separating the structure of grain and leguminous raw material into constituent components, as one of the most relevant areas of environmental protection and reducing the amount of wastewater from enterprises processing agricultural raw materials. The main direction of research on the production of protein concentrates from leguminous raw materials (peas, beans, chickpeas, lupine) by the method of air classification is noted. Among grain crops, rye stands out as having a more balanced amino acid composition compared to wheat and the largest starch grains up to 60 microns, which improves the aero-dynamic separation of grain flour into protein and starch fractions. Тherefore, rye flour was the object of research in this work. The research area included the development of a method for determining the starch content in the heavy fraction of rye flour from the yield of its light protein fraction and its starch content using an installation with variable parameters of a two-chamber disperser and a vortex classifier. The results of experiments on the separation of the mass of the initial rye flour into heavy starch and light protein fractions with a given ratio of starch and protein are theoretically justified and experimentally confirmed. The dependences of the starch content in the heavy fraction on the number of cycles of its recycling are established. With variable parameters of grinding rye flour, determined by the speed of the working bodies of the dispersant from 70 to 100 m/s, the time of grinding and recirculation of the heavy fraction of 30 s and the tangential speed of the classifier rotor of 15 m/s, stable results were obtained for the separation of starch and protein. Тhe yield of the heavy fraction of 72 % with a starch content of 85 % and the yield of the light fraction of 28 % with a mass fraction of protein of at least 26 %.

Hydrocracking of Heavy Fischer–Tropsch Wax Distillation Residues and Its Blends with Vacuum Gas Oil Using Phonolite-Based Catalysts

The Fischer–Tropsch heavy fraction is a potential feedstock for transport-fuels production through co-processing with fossil fuel fraction. However, there is still the need of developing new and green catalytic materials able to process this feedstock into valuable outputs. The present work studies the co-hydrocracking of the Fisher–Tropsch heavy fraction (FT-res.) with vacuum gas oil (VGO) at different ratios (FT-res. 9:1 VGO, FT-res. 7:3 VGO, and FT-res. 5:5 VGO) using phonolite-based catalysts (5Ni10W/Ph, 5Ni10Mo/Ph, and 5Co10Mo/Ph), paying attention to the overall conversion, yield, and selectivity of the products and properties. The co-processing experiments were carried out in an autoclave reactor at 450 °C, under 50 bars for 1 and 2 h. The phonolite-based catalysts were active in the hydrocracking of FT-res.:VGO mixtures, presenting different yields to gasoline, diesel, and jet fuel fractions, depending on the time of reaction and type of catalyst. Our results enable us to define the most suitable metal transition composition for the phonolite-based support as a hydrocracking catalyst.

Characterization Techniques Coupled With Mathematical Tools for Deepening Asphaltenes Structure

Asphaltenes constitute a heavy fraction of fossil fuels and their characterization is still a very difficult and challenging issue due to their complex and variable composition. Asphaltene components are highly condensed aromatic molecules having some heteroatom and aliphatic functionalities. Their molecular weights distribution span a wide range, from hundreds to millions of units, in dependence on the diagnostic used, leading to speculation about possible occurrence of self-aggregation. In the present work, mass spectrometry, with properly developed mathematical methods, size ex-clusion chromatography and X-ray diffraction analysis have been applied to asphaltenes for giving some further insight on their MW distribution and characteristics. The results here reported give further quantitative support to the experimental data interpretation already reported in previous works.

Witwatersrand composite paleoplacers

Background. The Witwatersrand gold province located in South Africa is the richest in the world. The Witwatersrand deposits are composite, where osmirids and diamonds are mined along with gold, silver and uranium. The genesis of the Witwatersrand deposits is controversial. Most local geologists support the hypothesis of the presence of paleoplacer deposits with subsequent metamorphic transformation of ore-bearing conglomerates. In addition, there are aeolian, hydrothermal-sedimentary, hydrothermal-sedimentary-metamorphic and magmatic models of ore formation.Aim. To establish the genesis of the Witwatersrand deposits.Materials and methods. Analysis of published literature and factual data.Results. Osmirids and diamonds are mined along with gold, silver and uranium from the composite Witwatersrand deposits. Such a set of useful components is not known in any of the deposits of magmatic or hydrothermal genesis. Considering the confinement of useful components to conglomerates, the detrital nature of most of the gold grains and the presence of various accompanying minerals in the heavy fraction, characteristic of igneous rocks of felsic, basic and ultrabasic composition, the hypothesis of the primary alluvial nature of the deposits of the Witwatersrand province looks the most reasonable.Conclusions. The factual material indicates an alluvial origin of the Witwatersrand deposits with subsequent metamorphic transformation of ore-bearing reefs. The primary alluvial formation of ore-bearing conglomerates is indicated by the confinement of gold and uranium to channel facies with a tendency to accumulate in the basal horizons of the reefs, the presence of rounded gold particles bearing the traces of transportation in alluvial flows, as well as a set of minerals in the heavy fraction of concentrate, characteristic of placers.

Belowground allocation and dynamics of recently fixed plant carbon in a California annual grassland soil

Plant roots and the organisms that surround them are a primary source for stabilized organic C, particularly in grassland soils, which have a large capacity to store organic carbon belowground. To quantify the flow and fate of plant fixed carbon (C) in a Northern California annual grassland, we tracked plant carbon from a five-day 13CO2 pulse field labeling for the following two years. Soil and plant samples were collected immediately after the pulse labeling, and again at three days, four weeks, six months, one year, and two years. Soil organic matter was fractionated using a sodium polytungstate density gradient to separate the free-light fraction (FLF), occluded-light fraction (OLF), and heavy fraction (HF). Using isotope ratio mass spectrometry, we measured 13C enrichment and total C content for plant shoots, roots, soil, soil dissolved organic carbon (DOC), and the FLF, OLF, and HF. The HF was further analyzed by solid state 13C NMR spectroscopy. At the end of the labeling period, the largest amount of 13C was recovered in plant shoots (60%), but a substantial amount (40%) was already found belowground in roots, soil, and soil DOC. Density fractionation of 4-week soil samples (from which living roots were removed) indicated that the highest isotope enrichment was in the mineral-rich heavy fraction, with similar enrichment of the FLF and OLF. At the 6-month sampling, after the dry summer period during which plants senesced and died, the amount of label in the FLF increased such that it was equal to that in the HF. By the 1-year sampling, 13C in the FLF had declined substantially and continued to decline by the 2-year sampling. 13C recovery in the OLF and HF, however, was qualitatively stable between sampling times. By the end of the 2-year experiment, 69% of remaining label was in the HF, 18% in the FLF and 13% in the OLF. While the total 13C content of the HF did not change significantly from the 4-week to the 2-year sample time, 13C NMR spectroscopic analysis of spring HF samples from 2018, 2019, and 2020 suggests that the relative proportion of aliphatic/alkyl functional groups declined in the newly formed SOC over the 2-year period. Simultaneously, aromatic and carbonyl functional groups increased, and the proportion of carbohydrate groups remained relatively constant. In summary, our results indicate that initial associations between minerals and root-derived organic matter are significant and form rapidly; by 4 weeks, a substantial amount (17%) of the total plant-derived 13C had become associated with the heavy fraction (HF) of soil. While the majority of annual C input cycles rapidly (<2-year timescale), a sizeable proportion (~12% of the original inputs) persisted for 2 years.

Relationship Between Tectonic Evolutions and Presence of Heavy Oil in The Central Sumatra Basin

Heavy oil is formed through biodegradation process of hydrocarbons, as well as water washing, in which light hydrocarbon fraction disappears and leaves the heavy fraction. Heavy oil is essentially an asphaltic, dense (low API gravity), and viscous that is chemically characterized by its high content of asphaltenes in the oil. Although variously defi ned, 25o API is set the upper limit for heavy oil. Heavy oil in the Central Sumatra Basin is evidently formed as a result of biodegradation and water washing (a hydrodynamic process within oil reservoir) mechanisms. These processes occur as result of tectonic uplift of the reservoir after it has been fi lled with hydrocarbons. Heavy oil reservoir depths in the Central Sumatra Basin are generally shallower than 1,000 feet (300-400 meters), at which surface water may may be associated with the reservoir hence enabling the heavy oil transformation. A combined geology, remote sensing/geographic information system ( GIS), geophysics, stratigraphy, and wellbased analyses is utilized to serve the study. It has been observed that within the northern part of the basin, heavy oil is mainly found in fi elds located within uphill fault blocks such as the up-thrown part of the Sebanga thrust fault with its Duri, Sebanga North, Kulin, Rantau Bais, Batang, Akar, and Genting fi elds. In the western part of the basin there are the Kumis, Kotalama and Pendalian heavy oil fi elds associated with Dalu-Dalu thrust fault and Gadang Island uplift. In total 51 fi elds/structures containing or suspected to contain heavy oil are associated with uplifted geological positions, hence showing the strong relations between tectonic evolutions and present day presence of heavy oil within the basin.