Coking Products Research Articles

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.

Atomic Layer Deposition of TiO2 Thin Films on the Inner Walls of Steel Tubes Increases Anti-coking Properties.

To suppress catalytic coking, TiO2 passivation films were deposited on the inner walls of SS316 stainless steel tubes by atomic layer deposition (ALD). Indentation test results showed a platform on the indentation curve of TiO2 films grown over 2000 ALD cycles due to internal stress-induced microcracks. In coking experiments, the TiO2-coated tubes exhibited a higher heat flux and lower pressure difference than bare ones. Analysis of the coking surface revealed that TiO2 thin film passivation can reduce the size and number of particulate deposits. At the same time, passivation treatment inhibits the formation of filamentous carbon and improves anti-coking performance by reducing the ability of the tube to adsorb amorphous deposition products. The coking surfaces of TiO2-coated tubes had less graphitization, indicating that the coking products had fewer defects and lower activated carbon contents.

Comparison of a laboratory-scale coke and a pilot-scale coke from matched coal

ABSTRACT A coke produced using a custom-built sole-heated oven and a coke prepared in a pilot-scale oven from a matched coal, were compared using a range of analytical techniques. The aim of this comparison was to assess to what extent the small-scale sole-heated oven can successfully replicate the production of pilot-scale oven cokes, and thus be used to rapidly prepare and screen a wide range of cokes for particular characteristics, e.g. abrasion resistance. The techniques applied included conventional methods and novel methods developed by our research team. These included microstructural and microtextural analyses of samples of each coke, and tribological, scratch test and fractographic analyses, each of which elucidates different strength attributes. These include microstructural weaknesses, abrasion resistance, and the strength of microtextural interfaces. The level of replication achieved indicates that the sole-heated oven, used in combination with an annealing step in a muffle furnace, can be beneficially used to model the pilot-scale oven.

Coking Products from Shale

The composition of distillates from shale resins produced by the semicoking of kukersite shale in a Kiviter gas generator is investigated by chromatography and mass spectrometry. It is enlightening to compare the coking products from the complete shale resins, light fuel-oil distillate, heavy fuel-oil distillate, and shale phenol fractions. The shale coke samples are investigated by electron microscopy and X-ray diffraction.

ИЗНАЧЕННЯ ДЕЯКИХ ЯКІСНИХ ХАРАКТЕРИСТИК ПРОДУКТІВ СПІКАННЯ ШИХТ З САПРОПЕЛІТОВИМ ВУГІЛЛЯМ

There have been considered issues of using of the sapropelic coals, which are mining from the working layers of the State Enterprise "Lvivvugillya", located within the Lviv-Volyn coal basin. A significant amount of bad-quality raw materials accumulated at the enterprises of the coal processing industry in this region requires to be involved in the treatment technique. The technical characteristics of the sapropelic coals of the kennelys class hinders to use it in the energy industry. We have proposed to use the low-ash grades of sapropelic coals as a component of the coking blends to improve its technical properties. For this purpose, samples of such coal were removed from the Mezhirechenskaya mine, coal layer n8 v (thin 2, lava No. 595), sampling depth 437.1 m. The second material for testing was samples of so named "gas " coal” (G), taken from the Lesnaya mine, layer n7 N , which has the ability to coke formation. Samples of the blends of different composition, including individual components, were tested for swelling number in a crucible according to ISO 501-81 and for the volatiles matter yield. Tests have shown that the swelling number of the blend samples does not exceed 3 on the standard scale, decreasing with an increase of the mass fraction of sapropelic coals, and the yield of volatile substances naturally decreases with an increase of the content of G in the mixture. Blends have also been tested for caking power by Gray-King method in accordance with ISO 502-82. At the same time the yield of liquid (the sum of tar and water) and gaseous (in summary) coking products were determined. It has been established that the formation of tar depends upon the composition of the blend, its maximum is observed when the ratio of the components by weight is 25 parts of sapropelic coal and 75 parts of G. It is shown that the addition of sapropelic coals to G improves coke quality and reduces the swelling number. The coking tar has been fractionated and investigated by IR- and UV-spectroscopy. It has been found that it is a mixture of aromatic compounds (represented by mono- and polycondensed structures) and alkanes. Oxygen-containing structures are represented by phenolic hydroxyl and ethers.

Coking and gas products behavior of supercritical n-decane over NiO nanoparticle/nanosheets modified HZSM-5

Endothermic hydrocarbon fuel of active thermal protection has great potential in cooling system. The bottlenecks for the practical application are the unsatisfied heat sink and severe coking issue. Here, NiO nanoparticle/nanosheet hybrid thin layers were successfully wrapped on the commercial HZSM-5 (denoted as ZSM-5@NiM), and showing significant modulation ability for the acidity properties of HZSM-5 to boost supercritical cracking of n-decane. The as-prepared catalysts make the NiO and HZSM-5 show synergistic effect which dramatically lowers the overall acidity of composite, thus changes the cracking path of n-decane, and results in effective anti-coking properties. ZSM-5@NiM decelerated many additional free radicals and generated more gases products by monomolecular beta cleavage reaction. Gases products also show positively correlating with the heat sink. The catalysts improve the heat sink of n-decane from 3.77 MJ/kg at 728 °C to 4.59 MJ/kg at 780 °C. Present work demonstrates that the introduction of nanostructured metal oxides into HZSM-5 will synergistically adjust the acidity of composite, leading to the manipulation of catalytic cracking path and extent, gas products, heat sink, coking behavior of supercritical n-decane, finally providing deep insights for the design and fabrication of catalysts for hydrocarbon fuel cracking.

Distribution Characteristics of Coking Products and Mechanism of Tar Lightening in Preparation of High-Strength Gasification-Coke with Low-Rank Coal Blending

During the preparation of high-strength gasification-coke with low-rank coal blending, evolution of pyrolysis tar and gas is still unclear for situations where large amounts of low-rank coal are blended. Herein, the effect of low-rank coal blending on the distribution of coking products was thoroughly investigated and the mechanism of tar lightening was studied by simulating the coking process with 1 kg laboratory-scale coke oven. The results showed that more liquids but less gases were formed compared to the theoretically calculated values due to a stronger cohesive interaction in the coal blending system. Moreover, the gas yield and volatile matters in dry ash-free basis (Vdaf) showed an opposite linear correlation for single coal and blended coal, probably due to this strong cohesive interaction. The facileness of long-chain aliphatic hydrocarbons to crack into low-molecular-weight hydrocarbons is attributed to their weaker interactions with more low-rank coal blends. The low-rank coal blending significantly promoted the release of phenols due to the presence of hydrogen-donor groups. In addition, more fractured branched alkanes inhibited the deep condensation of free radicals (cohesive compounds), which led to tar lightening in the low-rank coal blending system. In contrast, in the caking coal blending system (without the addition of low-rank coal), aromatization of fractured olefin terminals promoted deep condensation of cohesive free radicals, resulting in the formation of more heavy tar. The current study also demonstrated that the conversion of heavy tar into light products could be promoted by adjusting the input of low-rank coal during the caking coal upgrading process, thereby increasing the profitability of the coking process.

Synergistic Effect of Hydrogen Transfer Ability on the Co-carbonization of Different FCC Slurry Oil Fractions

The interactions within co-carbonization systems are of great importance in the production of premium cokes. In this study, the blending of the heaviest fluidized catalytic cracking slurry oil frac...

Production of High-strength Cokes from Non- and Slightly Caking Coals. Part II: Application of Sequence of Fine Pulverization of Coal, Briquetting and Carbonization to Single Coals and Binary Blends

Production of High-strength Cokes from Non- and Slightly Caking Coals. Part II: Application of Sequence of Fine Pulverization of Coal, Briquetting and Carbonization to Single Coals and Binary Blends

Production of High-strength Cokes from Non-/Slightly Caking Coals. Part I: Effects of Coal Pretreatment and Variables for Briquetting and Carbonization on Coke Properties

Production of High-strength Cokes from Non-/Slightly Caking Coals. Part I: Effects of Coal Pretreatment and Variables for Briquetting and Carbonization on Coke Properties

Effect of “cobalt–carbon nanotubes” catalysts on anthracene coking

Coking of anthracene at 400–600°C in the presence or in the absence of a cobalt catalyst supported on carbon nanotubes (CNTs) was studied for the first time. The coking products were examined by X-ray diffraction and electron microscopy. The CoO-CNTs catalyst considerably (by 50°C) decreased the temperature of the onset of coking and accelerated the coke formation. The presence of CoO-CNTs changed the coke morphology. Whereas coking of pure anthracene affords ~1 micron spherical particles of poorly crystallized carbon, in the presence of the catalyst, a carbon “coating” covering the CNT surface is formed.

Comparison of the Coking Products from Heavy Petroleum Tars and Heavy Catalytic-Cracking Gas-Oil

The slow coking of heavy petroleum tars and heavy catalytic-cracking gas-oil from AO Gazpromneft–Omskii NPZ (AO GPN–OPNZ) is considered. The liquid coking products of heavy oil residues are analyzed by gas chromatography, mass spectrometry, and IR spectroscopy. The variation in composition of the decomposition products in the coking of the two raw materials is described. The quality of the petroleum coke obtained is studied by optical microscopy and X-ray diffraction analysis.

INCREASING YIELD OF DISTILLATE FRACTIONS DURING COKING OF PETROLEUM RESIDUES

The research results of the influence of preliminary mechanochemical activation of heavy oil feedstock (oil-fuel, tar) on the output of their coking products are presented. Raw materials were activated by creating a cavitation effect when a hydrocarbon stream passes through a diffuser under a pressure. The pressure gradient on the diffuser ranged from 10 to 50 MPa, and the number of cycles of passage through the diffuser - from 1 to 5. It is shown that hydrodynamic cavitation processing results in a change in the physicochemical characteristics of heavy oil feedstock. The presented values of the raw material density and its fractional composition before and after processing suggest that the cavitation effect results in cracking reactions in the raw material. Changes in the characteristics of the raw material affect the change in the output of its coking products. It is established that as the pressure gradient and the number of impact acts increase, the yield of liquid coking products increases, and the yield of coke decreases. No relationship between the feedstock characteristics and the increase in the yield of distillate fractions as a result of prior cavitation effects has been established. At the same time, the preliminary mechanochemical activation of the raw materials leads to a decrease in the density and refractive index of the liquid coking products, a decrease in the temperature of their initial boiling point, and an increase in the content of hydrocarbons in the gasoline and kerosene fractions in them. The increase in the density and refractive index of the light fractions of the liquid coking products suggests that the aromatization process proceeds as a result of mechanochemical activation.

Estimation of the Yield of Coking Products by a Neural-Network Model

Mathematical analysis of experimental data regarding the quality of coal and coal concentrates and the yield of coking products provides the basis for neural-network models capable of predicting product yields. The predictions are compared with results obtained by traditional calculation and with production data for the yield of coking products.

Neural-Network Model for Predicting the Yield of Coking Products

Mathematical analysis of experimental data regarding the quality of coal and coal concentrates and the yield of coking products provides the basis for neural-network models capable of predicting product yields. Such predictions will ultimately be used to optimize coking batches in production conditions.

Contents of Ecotoxic Elements in Polish Coking Bituminous Coals and in Products of Coking

Ecotoxic elements include the ones which have a negative impact on human health and the environment, among others, mercury, arsenic and lead. Hard coal is a fuel which contains significant amounts of ecotoxic elements and the processes of coal combustion, coking and gasification are one of the main sources of their anthropogenic emission. In the coking process, individual ecotoxic elements in various proportions remain in coke and are released to the raw coke oven gas. During the cleaning and cooling of coke gas, ecotoxic elements are distributed between purified coke gas and other coking byproducts. In the paper, the measurement results of the contents of selected ecotoxic elements in the Polish coking bituminous coals are presented, i.e. mercury, arsenic and lead. The examination results of their content in the products of the coking process i.e. coke, coal tar, BTX, sulfur, and purified coke oven gas are also shown. Coke is characterized by a much lower content of mercury and lead than coal, and by a similar content of arsenic. Among the coking products, sulfur and tar are characterized by the highest content of mercury. Coal tar also contains a high amount of lead.

Effect of Vegetable Oils on Tar Coking

Tar coking in the presence of vegetable oils is studied. Use of vegetable oils as tar additives during coking is shown to have no significant effect on the total yield of vacuum distillates from the liquid coking products. However, their use could change the quantitative ratio of the obtained distillates.

PERSPECTIVES OF PRODUCING OIL ISOTROPIC COKE AS A FILLER OF CARBON CONSTRUCTION MATERIALS

The article is devoted to the problems of production of isotropic coke. Despite the wide variety of produced structural graphite types locally produced and produced by foreign firms, research into the creation of new high-density and high-strength graphite has not lost its relevance, and continues to develop intensively due to the growing demand and operational requirements for these materials. Traditionally in Russia, structural graphite were produced on the basis of petroleum pyrolysis coke of the brand KNPS according to GOST 22898-78 with a pseudo-isotropic structure. At present, the production of petroleum pyrolysis cokes and materials on their basis is lay-off. Raw materials locally produced analysis base for carbon raw materials (in particular for isotropic coke and pitches) indicates a virtually complete lack of sustainable providing with quality raw materials of consumers. Solution of organizing high-quality carbon raw materials industrial production task may lead to the decline of the country's carbon industry. The closure of the brand KNPS coke output is the reason to the search for new technologies for the production of structural graphite based on petroleum raw materials. Heavy pyrolysis oil has great interest as a potential raw material for the various carbon structural materials production, it consists of a large number of aromatic compounds and practically does not contain sulfur. There is comparing the heavy pyrolysis resins characteristics used as raw materials for producing isotropic coke. The aromatic hydrocarbons and carbohydrate particles in heavy pyrolysis influence pitches on the coking products structure is described. The rapid introduction of scientific achievements and best practices will contribute to the coke enterprises development.

Predicting the Yield of Coking Products

The properties of coal concentrates are determined: the technical analysis, clinkering properties, petrographic and elementary analysis, and the product yields in coking. Structural characteristics of the coal’s organic mass are also calculated. The results obtained for Kuznetsk Basin coal are subjected to mathematical analysis. The experimental dependences obtained may be used to formulate optimal coking batch in actual production conditions.

70 ナフタレンピッチをモデルとする触媒添加コークス製造の基礎研究(コークス製造,添加材)

70 ナフタレンピッチをモデルとする触媒添加コークス製造の基礎研究(コークス製造,添加材)