Biogenic native Sulfur linked to the Neogene deposits from the Riffian Corridors (Northern Morocco): preliminary study and characterization

<p>Elemental sulfur in sedimentary rocks is commonly associated with evaporites and authigenic carbonates. The genesis of this evaporite hosted native sulfur has been traditionally considered as a result of bacterial sulfate reduction under specific geological and paleogeographic conditions. Some biogenic sulfur occurrences are found in the Mediterranean area associated with the Neogene formations (e.g. Hellin, Lorca, Teruel, Sicily). They are described as interbedded layers in large evaporitic sequences or as sulfur nodules enclosed in secondary gypsum or carbonate deposits. Quite similar geological settings are present in Northern Morocco where several sediment-hosted sulfur showings were noted. However, these potential sulfur occurrences in the Pre-Rif and post-nappe Neogene basins have not been studied and still basically unknown. This work aims to explore these occurrences and assess their potentials using preliminary field, mineralogical and geochemical data. Several potential areas were identified at the Tortono-Messinian formations of Oued Amlil, Arbaa Taourirt, Taghzout Tassa, and Boudinar basins. They show favorable settings composed mainly of gypsiferous marls, carbonate, and organic matter-rich black sediments. In terms of sulfur contents, preliminary XRD data confirmed the presence of elemental sulfur and geochemical analyses show total sulfur content reaching 18.5 wt.%. However, further fieldwork combined with advanced mineralogical and isotopic geochemistry is still necessary for this area to try understanding their paragenesis in comparison with other similar Mediterranean occurrences.</p>

Predicting changes in the sulfur content during steam coal preparation and the level of sulfur dioxide emissions when its combustion

Purpose. Development of a method and forecast estimation of sulfur dioxide emission reduction during combustion of steam coal by regulating its quality during coal preparation. Methodology. Study on sulfur content in coal using sieve, fractional analysis, analysis of ash and total sulfur content. Forecasting of sulfur content in concentrate according to the developed calculation method. Production tests at the coal preparation plant. Forecasting of the level of SO2 emissions during pulverized coal combustion according to the developed calculation method. Findings. The distribution of sulfur content of Ukrainian steam bituminous coal by size classes depending on ash content is investigated; the proximity of sulfur content to the linear dependance on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The calculations of the level of SO2 emissions during pulverized combustion of coal and its cleaned products taking into account their elemental composition is performed, and the linear dependence of the level of SO2 emissions on the total sulfur content to lower heating value (LHV) ratio is proved. Based on the obtained results, methods are developed for determining the expected sulfur content in the concentrate and the forecasted level of SO2 emissions during its combustion; the optimal depth of preparation for the coal from various mines is determined by the criterion of compliance of the SO2 emission level with the current environmental standards. Originality. Proximity of the sulfur content to the linear dependence on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The linear dependence of the level of SO2 emissions on the ratio of the total sulfur content to LHV during pulverized combustion of coal and its clean products is proved. Practical value. A method has been developed for determining the expected sulfur content in the products of coal preparation by jigging, taking into account the allowable content of the high-density fraction in the concentrate and adding dense slimes to the coal preparation products. A method has been developed for determining the predicted level of SO2 emissions during their combustion. The optimal depth of the coal preparation for coal from various mines has been determined by the criterion of compliance of the level of SO2 emissions with the current environmental standards.

Raw material base for coking of the Coke Production of PJSC "ARCELORMITTAL KRYVYI RIH" in the period from 2017 to 2021.

RAW MATERIAL BASE FOR COKING OF THE COKING PRODUCTION OF PJSC "ARCELORMITTAL KRYVYI RIH" IN THE PERIOD FROM 2017 TO 2021 © N.V. Mukina (Coke-chemical production of PJSC "ArcelorMittal Kryvyi Rih", 50095, Dnepropetrovsk region, Kryvyi Rih, Krivorozhstal st., 1, Ukraine), D.V. Miroshnichenko, Doctor of Technical Sciences (NTU "Kharkiv Polytechnic Institute", 61002, Kharkiv, st. Kirpicheva, 2, Ukraine) The article presents the data on coal components that were used in the charge for coking coke oven batteries №№1-4 (bulk coal charge) and №№ 5, 6 (tamped coal charge) of the coke-chemical production of PJSC "ArcelorMittal Kryvyi Rih" in the period from 2017 to 2021, as well as averaged information on some quality indicators of the produced coke. In general, the coal raw material base of the enterprise for the last five years has been of a stable inter-basin nature with a predominance of coals from the USA, Kazakhstan, and the Russian Federation. It is shown that, as the tamping technology suggests, moisture content, bulk density and content of classes less than 0.16 and less than 3.0 mm in coal charges supplied to the coal waste plant. №№ 5, 6 are significantly higher than the values of similar indicators of coal charges supplied to the numbers 1-4. Along with this, due to the use of coals of a certain quality, ash content, total sulfur content and the thickness of the plastic layer in coal charges supplied to the coal bunker №№ 1-4, is slightly higher than similar indicators of coal charges supplied to the boiler №№ 5, 6. In total, during 2017-2021, the composition and quality indicators of the coal charge for the production of coke at the boiler plant №№ 1-4 practically did not change, while in the coal charge for the production of coke on coke oven batteries №№ 5, 6 there is a decrease in the share of highly volatile coals with a simultaneous increase in the content of medium-volatile and low-volatile components. The given values of the quality indicators of the obtained blast-furnace coke indicate that the use of tamping technology makes it possible to obtain blast-furnace coke of a higher quality than by using a traditional technology. In particular, the coke obtained at the oven batteries №№ 5, 6 are characterized by lower values of ash content, total sulfur content and abrasion (M10) with higher values of mechanical strength in terms of M25 and post-reaction strength (CSR). Keywords: coal, inter-basin raw material base, coking, charge tamping, coke quality. Corresponding author N.V. Mukina, е-mail: [email protected]

Mathematical Modeling of the Process Hydrotreatment of Diesel Fuel Based on the Kinetic Characteristics of Its Fractions

The principles of mathematical modeling of the diesel fuel hydrotreatment process as a multicomponent reaction system are considered. Feedstock containing a large number of organosulphuric components from the standpoint of increasing the level of model adequacy and calculation accuracy can be characterized by the total sulfur content in the raw material as a whole (1), the total sulfur content in pseudocomponents in the feedstock or its narrow fractions (2), the concentration of individual organosulphuric substances (3). It is shown that in cases 1 and 2, the concept of the reaction rate constant as a constant that characterizes the physico-chemical process is degenerate, and in calculations it should be considered as a kinetic characteristic that takes into account the inhomogeneity of the chemical process over time. As the hydrogenated feedstock comes into contact with the hydrogen-containing gas, the most active organosulfuric components with a high reaction rate constant are first hydrogenated on the catalyst, and at the final stage of the process, the less active components with a low reaction rate constant are hydrogenated. Examples of calculating the dependence of the kinetic characteristic and the total sulfur content in the hydrogenate in two broad fractions of diesel fuel on the time of contact of the reaction medium with the catalyst and the subsequent compounding of the fractions into diesel fuel.

QUALITATIVE CHARACTERISTICS OF THE COAL DEPOSIT KOTEZI IN THE BUGOJNO BASIN

This paper presents study results of the qualitative characteristics of coal deposit Kotezi. Regional geological researches were conducted from 1983 to 1987, and detailed from 2014 to the end of 2018. Tests were performed on the following coal quality parameters: average thickness of pure coal in coal layers, total moisture content, ash content, total sulfur content and lower heat value. Researches were conducted in the field, laboratory and cabinet. Subsequently, an analysis and interpretation of the obtained research results was carried out. Comparing the research geological results of all represented coal layers, deviations of the considered parameters were determined. Coals of the Bugojno basin belong to the younger coals, soft to medium hard, no luster (matt), brown to black colored, and have brown streak. Their fracture is plate-like and particleboard. They do not have a distinct lignite structure, except in the lower layers. With their general habitus, they resemble younger brown coals, and belong to humic coals which are relatively low in carbonation. In the vertical profile of coal layers, the highest quality components are from the upper part of the layer, while the slightly lower quality components are from the middle and lower parts of the layer.

Development of Cryptocrystalline Graphite Desulfurization Methods

Increasing demands on the quality of graphite cause carrying out detailed studies of its desulfurization. Combined sulfur present in natural graphite reduces the heat transfer coefficient, increases the heat energy consumption, pollutes the atmosphere with harmful emissions in the process of their application in various branches of industry. The technology and deepness of desulfurization is determined by the total content and ratio of various sulfur compounds in graphite. Previously, a number of technologies for cryptocrystalline graphite enrichment had been developed by the authors. However, the use of these technologies does not effectively reduce the sulfur content in the graphite composition. Therefore, the aim of this work is to develop activation methods that can reduce effectively the sulfur content in the composition of cryptocrystalline graphite. In order to reduce the total sulfur content, mechanical and electro-explosive-pulsing activation were tested. Mechanical activation of graphite was carried out in АGО-2, DCM, D-100 activator mills in different environments and at different activation time. To implement electric-explosive-pulsing activation, special equipment was used. In the process of the research it has been found that the use of mechanical activation and electric-explosive-pulsing activation does not reduce the sulfur content below 0.25 wt.%. Mechanical activation of graphite in different modes enables more intensive release of sulfide minerals from aggregate graphite formations and their intensive oxidation.

Characterization of bio-coal briquettes blended from low quality coal and biomass waste treated by Garant® bio-activator and its application for fuel combustion

Experimental research was carried out on the manufacturing of bio-coal briquettes from a blend of two different types of low-quality coal and biomass waste in the absence of coal carbonization, where the third blend of the material was fermented by adding a bio-activator solution before pressurizing the components into briquettes. The coal samples from Caringin–Garut Regency (BB–Garut) had a low calorific value and a high sulfur content (6.57 wt%), whereas the coal samples from Bayah–Lebak Regency (BB–Bayah) had a higher calorific value and a lower sulfur content (0.51 wt%). The biomass added to the coal blend is in the form of fermented cow dung (Bio–Kohe), and it had a calorific value of 4192 kcal/kg and a total sulfur content of 1.56 wt%. The main objective of this study is to determine the total decrease in the sulfur content in a blend of coal and biomass in which a fermentation process was carried out using a bio-activator for 24 h. The used bio-activator was made from Garant® (1:40) + molasses 1 wt%/vol, and its used amount was 0.2 L/kg. Also, the total sulfur content in the blend was 1.00 wt%–1.14 wt%, which fulfills the necessary quality requirements for non-carbonized bio-coal briquettes. The pyritic and sulfate content in the raw coal was dominant, and the organic sulfur, when fermented with Garant®, was found to be less in the produced bio-coal briquettes by 38%–58%.

Total Sulfur and Ash Yield of Tanjung Formation Coal in Sekako, Barito Basin, Central Kalimantan: Implication of Depositional Process

Tanjung Formation is one of the major coal-bearing deposit in the Barito Basin, Central Kalimantan. The distribution of total sulfur and ash yield in coal is closely related to the depositional environment. This study was to determine the total sulfur and ash yield and the interpretation of the dynamics of depositional process. Coal seam A and B generally have low to medium ash yield 2.82 to 9.23 (wt.%, db) and low total sulfur content of <1 (wt.%, db), except for the 6PLY1 coal sample which has total sulfur content that relatively high at 1.55 (wt.%, db). Coal samples 5PLY1A, 5PLY1B, 5PLY3, 5PLY5, 6PLY2, 6PLY4, 6PLY5, 6PLY7, and 6PLY9 which have low to medium ash yield and low total sulfur content <1% (wt.%, db) are formed in the topogeneous mire (freshwater swamp) in a fluvial environment. The total sulfur content was interpreted to be derived mainly from the parent plant materials. Meanwhile, the 6PLY1 coal sample which has an ash yield of 5.83 (wt.%, db) and total sulfur content of 1.55 (wt.%, db) formed in topogeneous mire in an environment that is invaded by sea water, and the total sulfur content were interpreted coming from the parent plant materials and the effect of seawater invasion which is rich in sulfate (SO4) compounds. It is also supported by the occurrence of syngenetic mineral content (framboidal pyrite) and epigenetic pyrite of 1.23 (vol.%).