Sulfur Content Of Coke Research Articles

The Influence of Organic and Inorganic Additives on the Specific Electrical Resistance of Coke

This study aimed to evaluate the effect of both inorganic (boron carbide nanopowders and silicon carbide (carborundum) and organic lean (petroleum coke) additives on the quality of coke produced in a laboratory furnace, as well as on its electrical properties. Analyzing the results of the quality assessment of the obtained coke, it can be argued that the addition of a fixed amount (0.25-0.5 wt.%) of non-caking nanoadditives allows to regulate the process in the plastic state in order to increase the coke strength. This modification affects the coke quality and has a significant dependence on the grade composition of the coal charge. The use of nanoadditives is especially important for coal charges with poor coking properties. Adding 5% of petroleum coke to the coal charge leads to an increase in the gross coke yield by 1.2-1.3%; a decrease in coke ash content by 0.2-0.3%; an increase in the total sulfur content in coke by 0.15-0.23%; deterioration in both mechanical (P25 − by 0. 1-0.6%; I10 − by 0.1-0.2%) and coke strength after the reaction (CSR - by 0.6-1.0%), coke reactivity (CRI - by 0.2-0.3%), as well as structural strength (SS by 0.3-0.4%), abrasive hardness (AH by 0.7-1.0 mg) and specific electrical resistance (ρ by 0.002-0.007 Om×cm). The obtained data may indicate an increase in the order degree of the coke structure and the appearance of a larger number of nanostructures. In addition, it should be noted that a sharper deterioration in blast furnace coke quality is observed when using a coal charge characterized by a lower coal content of the Concentrating Factory Svyato-Varvarynska LLC.

INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE COMPOSITION AND PROPERTIES OF PETROLEUM COKE

This study is devoted to studying the complex process of producing coke from heavy oil residues using previously developed experimental approaches and using analytical methods of analysis. The purpose of the study is to produce low-sulfur coke by thermal processing of heavy oil residues in the presence of waste motor oils. The resulting coke was analyzed by various physicochemical methods. The composition and structure of the resulting coke were studied using Raman spectroscopy methods. As a result of the analysis, the predominance of polyaromatic compounds and olefins in the coke composition was revealed. Electron microscopy techniques provided a visual representation of the microstructure and morphology of coke samples obtained both in the presence and absence of a recycling agent. Significant results were obtained by measuring the specific surface area of coke, which highlight the significant influence of temperature fluctuations on its characteristics of coke. It is noteworthy that the specific surface area of micropores varies significantly – from 16 to 600 m2/g. The results of the analysis of sulfur content showed the possibility of its thermal dehydration, which should lead to an improvement in the quality of coke. In addition, it has been shown that conducting the experiment in the presence of a recycling agent significantly increases the yield of coke and opens up prospects for more efficient use of heavy oil residues. Taken together, the results provide valuable insight into the intricacies of producing low-sulfur coke from heavy petroleum residues. In addition to industrial significance, this research also has environmental significance, since it proposes an approach that allows not only to maximize the use of secondary resources, but also to reduce the sulfur content in coke, which will help limit the environmental impact of industrial processes.

Effects of Additives on Coke Reactivity and Sulfur Transformation during Co-pyrolysis of Long Flame Coal and High-Sulfur Coking Coal.

A silica-aluminum-based mineral (GL) was selected for inspecting the effects of interactions of minerals in coal blends on the coke reactivity index (CRI) and sulfur transformation during co-pyrolysis of long flame coal and high-sulfur coking coal. Results indicate a good compatibility for the supply of active hydrogen, decomposition of sulfur, and regulation of reactivity. The experimental values of sulfur content in different coal blend cokes are lower than the calculated values, which can be determined as a result of the directional regulation effect of long flame coal on sulfur transformation. The addition of GL in coal blends significantly reduces the CRI of the corresponding coke, and the effect of GL on coke reactivity is also verified by a 10 kg coke oven experiment. When increasing the ratio of long flame coal, the sulfur fixation in the solid phase has a tendency to be enhanced by alkaline minerals. Also, GL plays a role in reducing the capture of sulfur free radicals by alkaline minerals, which improves the sulfur removal during pyrolysis of coal blends and then reduces the sulfur content in coke. This work provides a reference for using silica-aluminum-based minerals to reduce the capture of sulfur and catalytic effect on coke reactivity.

Structural difference of gas coal separation components and its effect on sulfur transformation during pyrolysis of high sulfur coal

Two gas coals were respectively separated into four components with different vitrinite content using ZnCl2 solution. The carbon structure, composition of coal macerals and minerals, and plastic layer behavior of separating components were characterized by nuclear magnetic resonance spectrometer (13C NMR), coal petrographic analyzer, X-ray fluorescence spectrometry (XRF) and Gieseler fluidity. Combining with X-ray photoelectron spectroscopy (XPS), effect of different gas coal separation components on sulfur transformation behavior during pyrolysis of high-sulfur coal and distribution of sulfur forms in coke was investigated. The results show that with increase of vitrinite content in gas coal, the relative ratio of aliphatic carbon in coal increases, and the release amount of volatiles increases during pyrolysis; hydrogen free radicals in volatiles promote decomposition of sulfur, stabilize sulfur free radicals in time and release as sulfur-containing gases, and thus sulfur content in coke is reduced. Low density components in gas coal have the largest maximum fluidity and widest plastic range, and stability of plastic layer is the best during co-pyrolysis with high sulfur coal. The basic minerals in gas coal are mainly enriched in high density components, which leads to increase of sulfide sulfur and sulfate sulfur in the coke. For utilization of gas coal in coal-blending pyrolysis, enrichment of vitrinite and selection of coals with easier removal of alkaline minerals are beneficial for reducing sulfur in coke.

Подбор сырья для получения качественного игольчатого кокса

The aim of the study is to study the possibility of obtaining anisotropic needle coke, using various types of heavy pyrolysis resin, decantoil and a mixture of decantoil and heavy pyrolysis resin as raw materials in laboratory conditions. The coking process was carried out at a temperature of 470°C in a laboratory installation of periodic action in static conditions. A study of the influence of the composition of raw materials on such important indicators of coke as the sulfur content in coke and the assessment of the microstructure according to a special ball technique The production of cokes with a low scoring is due to the fact that under static conditions there is no directed movement of the flow of the raw material mixture, as is realized in industrial plants for delayed coking.

Transformation and regulation of sulfur during pyrolysis of coal blend with high organic-sulfur fat coal

Sulfur transformation and distribution during pyrolysis of an industrial coking coal blend with a high organic-sulfur fat coal was studied in a fixed-bed reactor. Sulfur K-edge X-ray absorption spectroscopy was used to study the sulfur speciation in cokes. Two coals with high volatiles were selected to regulate the sulfur transformation behavior during pyrolysis and the interactions between volatile matters and nascent cokes were investigated. The addition of high organic-sulfur fat coal to coal blend resulted in the increase of sulfur content in coke, but the desulfurization rate also increased during coal blend pyrolysis. Higher amount of sulfur-containing radicals in volatile matters from high organic-sulfur fat coal promoted the interactions with nascent coke and resulted in the higher sulfur retention on the coke surface. Adding high volatile coal into coal blend affected the interactions between different coals and the sulfur transformation. The interactions between sulfur-containing radicals and nascent coke could be inhibited by volatile matters from high volatile coals. Further characterizations confirmed that the volatile matters from high volatile coal, which had a more overlapping temperature range to sulfur release in coal blend, leading to the lower sulfur content in coke, higher desulfurization and weaker S K-edge spectral intensity. The interactions between external volatile matters and nascent coke primarily occurred on the coke outer surface.

Effect of Operating Conditions and Additives on the Product Yield and Sulfur Content in Thermal Cracking of a Vacuum Residue from the Abadan Refinery

Thermal cracking of a vacuum distillation residue of the Abadan refinery in Iran was performed under delayed coking conditions to investigate the effect of operating conditions on the yield and sulfur content of products. At reaction temperatures of 440–500 °C and pressures of 1, 3, and 5 bar, the products included gases, liquids, and coke. The yields of liquid products were higher at 1 bar compared to those for higher pressures. Increasing the reaction temperature at a given reaction pressure led to an increase in the yield of liquid products. Increasing the reaction pressure at a given reaction temperature led to higher yields of coke and gases as well as a decrease in the sulfur content of coke and liquid products. The effects of iron oxide and aluminum oxide nanoparticle additives on the product yields and sulfur content were also investigated. The results indicated that different concentrations of additives would increase the liquid yields and decrease the sulfur content of both coke and liquid produ...

GALVANO-COAGULATION PROCESSING OF GAS-CLEANING SOLUTIONS AT ALUMINUM WORKS FOR THE PURPOSE OF SODIUM SULFATE REMOVAL

An analysis of the effect of increasing the sulfur content in coke used in the production of anode mass on the sodium sulfate content in gas cleaning solutions at aluminum plants has been carried out. The methods to remove Na2SO4 from gas cleaning solutions and over-slime waters in slime storage tanks and the problems in their realization are described. Application of galvano-coagulation process for this purpose is shown to allow realizing up to 80 thousand m3 of slime storage tanks as well as reducing the energy consumption by 5–7 % for transportation of salt-free solutions in pipeline network.

Reducing the sulfur content of coke by increasing the content of thermally conditioned g coal in the batch

In periods of economic growth, Ukrainian coke plants face a shortage of Zh and K coal, because of the high demand. In periods of economic stagnation, conversely, there is an excess of Zh coal, on account of the drop in demand. However, it is still important to introduce poorly clinkering coal in the batch. Ukrainian coal is known to have high sulfur content (up to 3.5% S). About 45–75% of that sulfur is passed on to the coke. Consequently, in order to reduce the sulfur content of the coke, it is expedient to include poorly clinkering coal in the batch, since typical low-carbon Donets Basin coal has a low desulfurization coefficient: 0.63. The corresponding figure for moderate-carbon coal is 0.70. Hence, by increasing the content of poorly clinkering coal in the batch, the sulfur content and cost of the coke may be reduced.

Sulfur distribution in coke and sulfur removal during pyrolysis

In order to investigate the mechanisms of coke desulfurization by blowing additional gas into coking chamber during pyrolysis process, some experiments were conducted to study the effects of some factors on the distribution of sulfur in coke. These factors include pyrolysis temperatures, the kinds of the blowing gases and the diameters of coking chamber. It was found that sulfur was mainly released at the range of 300–600 °C. Under this temperature range, the sulfur content in coke can be reduced by 0.05–0.06% by blowing N 2, CO or CH 4, and by 0.14% by blowing H 2 at a space velocity of 1.2 mm/s compared with the absolute sulfur content of 0.92% in the case without gas feeding. Obviously, H 2 is more effective on sulfur removal than N 2, CO or CH 4. The total, organic and inorganic sulfur contents in coke increase with increasing the diameter of coking chamber under identical pyrolysis conditions. Both organic and inorganic sulfur contents in coke increase regularly from the center to brim at identical height of a coke column for all the cases. In addition, the organic and inorganic sulfur contents at the cranny surface are higher than those in interior at the same sampling position. X-ray photoelectron spectroscopy (XPS) analyses suggest that the main contributions to the increase of inorganic and organic sulfur contents are due to the formation of negative bivalent sulfur and thiophenic compounds, respectively.

Sulfur groups in the cokes obtained from coals of different ranks

Coals of different ranks having their sulfur content distributed in different forms were heated up to 1000°C. It was shown that the higher the rank of the coal the more sulfur remained in the coke. The retention of sulfur in the coke is strongly dependent on the proportion of the thiophenic sulfur in the organic coal sulfur. The sulfur in the cokes examined was mainly organic in form. Iron sulfide, FeS, constituted most of the inorganic sulfur. A correlation was observed between the sulfide sulfur content in coke and the pyritic sulfur content in coal. The form and size of the iron sulfide present in the coke were determined by microscopic examination.

Influence of feedstock origin and distillation range on yield and sulfur content of coke

Influence of feedstock origin and distillation range on yield and sulfur content of coke