Petroleum Coke Research Articles

Innovation Research of Waste Biomass and Petroleum Coke for the Carbothermic Reduction Process of Silica

Innovation Research of Waste Biomass and Petroleum Coke for the Carbothermic Reduction Process of Silica

Catalytic pyrolysis of microalgal lipids to liquid biofuels: Metal oxide doped catalysts with hierarchically porous structure and their performance

Catalytic pyrolysis of lipids is an alternative pathway for alternative aviation fuel production with advantages of H2-free and mild reaction conditions. However, it is still hindered by coking of catalysts and low selectivity of kerosene. In this research, composite catalysts were synthesized via postsynthesis method (alkali treatment) followed by doping of metal oxides (ZnO, La2O3, and CeO2). Catalytic performance of as-synthesized catalysts was evaluated during catalytic pyrolysis of microalgal lipids. The characterization of BET, XRD, SEM, NH3-TPD for catalysts indicated that alkaline treatment increased the mesoporous structure (5.28–5.91 nm) of microporous zeolite HZSM-5 to form a hierarchically porous structure without apparent disruption of crystal structure of zeolite, while doping of metal oxides (about 10 wt%) enhanced the performance of hetero-atoms (oxygen and nitrogen) removal. The acidity of as-synthesized catalysts significantly decreased from 1175.61 μmol/g (HZSM-5) to 406.77 μmol/g (Ce-MHZ). After catalytic pyrolysis carbon number distribution and compound type of produced liquid fuels tended to high kerosene components (above 40%) and increased hydrocarbon content with reduced content of oxygen-containing compounds. The hierarchically porous zeolite also presented aromatization for aromatic hydrocarbons in alternative aviation fuels. Catalytic mechanism was also elucidated including complex reactions of decarboxylation, decarbonylation, carbon chain cracking, and aromatization.

Synergism between lignite and high-sulfur petroleum coke in CO2 gasification

Abstract High-sulfur petroleum coke (PC) as solid waste has high treatment cost. Gasification technology can utilize PC and lignite for co-gasification. Organically combining the two is the key to expanding the adaptability of gasification raw materials. This work used thermal analysis technology to study the gasification reaction of PC and lignite systems in a CO2 atmosphere. The results show that the starting and end temperatures of the co-gasification of lignite/high-sulfur PC are lower than those of pure coke. The improved carbonization rate and gasification reaction index indicate that lignite improves the gasification performance. The gasification synergy factors are all greater than 1, indicating that the co-gasification process produces obvious synergism, and the synergism is more obvious in the gasification stage after 800°C. The lignite ash is gradually enriched on the surface of high-sulfur PC with the temperature increase, and the Ca and Fe elements have an obvious catalytic effect, but the catalytic effect has a saturation value. Ashes from lignite used as a multi-component gasification catalyst can increase the overall reactivity in the lignite/high-sulfur PC system, which can broaden the selection of gasification raw materials, and make efficient use of the resource characteristics of both.

The molecular evolution mechanism of direct pyrolysis and hydropyrolysis of Changqing petroleum coke was compared based on ReaxFF method

The molecular evolution mechanism during the direct pyrolysis and hydropyrolysis of Changqing petroleum coke was investigated using the ReaxFF (Reactive Force Field) modeling approach. The corresponding hydrogenation pyrolysis model was constructed with the petroleum coke macromolecular model. Through the same LAMMPS workflow setting, the two simulated molecular number changes, main product changes, typical hydrocarbon gas evolution, and the initial transfer of nitrogen atoms were analyzed. The results show that: hydrogenation pyrolysis not only advances the initial state of pyrolysis, but also extends the end of the pyrolysis; hydrogenation pyrolysis is conducive to the more sufficient pyrolysis reactions; And the overall reaction time is less than direct pyrolysis. At the level of the atom level, the direct pyrolysis of the molecule and the hydrogenation pyrolysis were divided into a distinction. These conclusions have certain guiding significance in the cleaning and utilization technology of heavy oil and petroleum coke industry.

Fractographic studies and tensile strength of MPG-6 graphite based on uncalcined coke, neutron-irradiated at a high temperature

This paper presents the results of studies of the mechanical properties and fracture characteristics of MPG-6 graphite in the unirradiated state and neutron-irradiated at high temperature. MPG-6 is considered as a material for future high-temperature gas-cooled reactors (HTGR). In particular, MPG-6 is considered as one of the candidate materials for prismatic fuel blocks of the Russian experimental hydrogen-producing nuclear power plant with the VTGR high-temperature reactor currently under design.It is shown that MPG-6 graphite, based on uncalcined petroleum coke, which causes a small difference in the size of crystallites in areas with different preferred orientations of crystallites, has higher radiation stability of mechanical properties than GR-280 graphite based on calcined coke.

EXPERIENCE IN OBTAINING PRODUCTS OF THE DELAYED COKING PROCESS USING VISBREAKING RESIDUE AND CATALYTIC CRACKING HEAVY GAS OIL AS FEEDSTOCK

The authors have analyzed the literature data on delayed coking process. There have been considered the following: feedstock bases for petroleum coke production; implementation and development of delayed coking process; the types of products obtained. It has been revealed, that the main feedstocks for the process are heavy fractions of oil: fuel oil, semihudron, tar, various heavy oil residues, etc.In order to expand the feedstock base, the authors conducted laboratory studies concerning the use of visbreaking residue and catalytic cracking heavy gas oil in the coking process. During the research: raw materials (visbreaking residue and catalytic cracking heavy gas oil) were analyzed; the coking process was carried out; the results of obtaining petroleum coke from visbreaking residue and catalytic cracking heavy gas oil were compared.It has been proved that visbreaking residue and catalytic cracking heavy gas oil can be involved in the process of delayed coking. It has been revealed that the best option for obtaining coking products is precisely catalytic cracking heavy gas oil.

RESEARCH OF THE PETROLEUM COKE THERMAL PROPERTIES IN ACTIVATED CARBON PRODUCTION PROCESS

Petroleum cokes are the products of deep thermal processing of heavy oil residues – asphaltenes, resins, fuel oil, tar, etc. The high carbon content in petroleum cokes composition and the ability to thermal modification make them a promising raw material to product activated carbons. This paper presents the results of studies of petroleum coke obtained by the method of delayed coking, with an increased yield of volatile substances as raw materials to use in activated carbon technology. Based on the results of thermogravimetric analysis and analysis of technological parameters of obtaining petroleum coke, the modes of thermal modification of samples in the process of obtaining activated carbon were selected. The pyrolytic gas chromatography method was used to identify the products of thermal decomposition of petroleum coke samples at different stages of activated carbon production technology. It is shown that the main gaseous products of pyrolysis are polycyclic aromatic hydrocarbons that release in the temperature range from 200 to 600 °C. During pyrolysis of carbonized coke samples, gaseous products do not release, and during pyrolysis of activated coke, the release of furan compounds and benzene is observed. Samples of petroleum coke modified with a solution of nitric acid, during pyrolytic analysis, show a complete absence of volatile pyrolysis products. Based on samples of petroleum coke that have been pretreated by various methods, series of activated carbon samples were obtained and their porous structure was studied. The use of a nitric acid solution for pretreatment of a sample of petroleum coke led to an increase in specific surface area and volume of sorption pores over 30-47%. For citation: Farberova E.A., Pershin E.A., Maksimov A.S., Khodyashev N.B., Smirnov S.A., Kuz’minykh K.G. Research of the petroleum coke thermal properties in activated carbon production process. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 102-110. DOI: 10.6060/ivkkt.20236606.6776.

Investigation of Petroleum Coke Gasification with CO2/H2O Mixtures and S/N Removal Mechanism via ReaxFF MD Simulation.

The removal of environmentally harmful S/N is crucial for utilization of high-S petroleum coke (petcoke) as fuels. Gasification of petcoke enables enhanced desulfurization and denitrification efficiency. Herein, petcoke gasification with the mixture of two effective gasifiers (CO2 and H2O) was simulated via reactive force field molecular dynamics (ReaxFF MD). The synergistic effect of the mixed agents on gas production was revealed by altering the CO2/H2O ratio. It was determined that the rise in H2O content could boost gas yield and accelerate desulfurization. Gas productivity reached 65.6% when the CO2/H2O ratio was 3:7. During the gasification, pyrolysis occurred first to facilitate the decomposition of petcoke particles and S/N removal. Desulfurization with the CO2/H2O gas mixture could be expressed as thiophene-S → S → COS → CHOS, thiophene-S → S → HS → H2S. The N-containing components experienced complicated mutual reactions before being transferred into CON, H2N, HCN, and NO. Simulating the gasification process on a molecular level is helpful in capturing the detailed S/N conversion path and reaction mechanism.

Polypropylene cracking on embryonic and ZSM-5 catalysts – An operando study

A series of ZSM-5 zeolites (embryonic, microporous, hierarchical) is studied in the catalytic cracking of polypropylene in the framework of its chemical recycling. Two important zeolite features impact their catalytic performances and allow their design as efficient catalysts: porosity and acidity. They also play a key role in catalyst deactivation and regeneration. A detailed thermogravimetric and spectroscopic (operando FT-IR) analysis of the reaction, including catalyst coking and regeneration, shows the emergence of rules to design fit-for-purpose catalysts to be used in existing or grass-roots FCC units.

Preparation of High-Quality Silicon with Silicon Cutting Waste by a Carbothermal Reduction Method

Silicon cutting waste (SCW) mainly consists of Si (80 ~ 85 wt%), SiO2 (13 ~ 16 wt%) and other impurities (2 ~ 4 wt%). Nowadays, the Si in SCW is commercially recycled to produce Si ingots by a slag refining method, but the SiO2 in SCW is melted into silicon slag and discarded as waste. In this paper, a carbothermal reduction method has been proposed for recycling Si resources from both Si and SiO2 in SCW to prepare high-quality silicon in a submerged arc furnace. Petroleum coke was selected as the carbonaceous reducing agent. Firstly, the effects of carbon content on the equilibrium compositions of the Si-SiO2-C system were simulated. Secondly, SCW was mixed with petroleum coke under the guidance of thermodynamic analysis results. Finally, the mixtures were charged into furnace and smelted. Thermodynamic equilibrium analysis results showed that the value of n(Si):n(C):n(SiO2) should be controlled as 2.62:0.22:0.44 theoretically. Experimental results revealed that the recovery ratio of SCW was 50% and the purity of Si products was 99.40%. This proposed method provides an effective and industrialized applicable approach for recycling SCW.

Controlling Diels-Alder reactions in catalytic pyrolysis of sawdust and polypropylene by coupling CO2 atmosphere and Fe-modified zeolite for enhanced light aromatics production

Producing value-added light aromatics (BTEX) from solid waste streams holds excellent promise for resource recovery. Here we present a thermochemical conversion approach that enhanced BTEX production by coupling CO2 atmosphere and Fe-modified HZSM-5 zeolite to facilitate the Diels-Alder reactions in catalytic pyrolysis of sawdust and polypropylene. The Diels-Alder reactions between sawdust-derived furans and polypropylene-derived olefins could be controlled by tuning CO2 concentration and Fe loading amount. Sufficient CO2 (≥50%) with moderate Fe loading (10 wt%) were observed to produce more BTEX and fewer heavy fractions (C9+aromatics). To deepen the mechanistic understanding, quantification of polycyclic aromatic hydrocarbons (PAHs) and catalyst coke was further conducted. The co-use of CO2 atmosphere and Fe modification suppressed the appearance of low-, medium-, and high-membered ring PAHs by over 40%, decreased pyrolysis oil toxicity from 42.1 to 12.8 μg/goil TEQ, and transformed coke from "hard" to "soft". Based on the characterization of CO2 adsorption behavior, it was deduced that the introduced CO2 was activated by loaded Fe and reacted in situ with H2 generated during aromatization to expedite H-transfer. Meanwhile, BTEX recondensation was prevented through the Boudouard reactions of CO2 and water-gas reactions between the resulting water and carbon deposits. These synergistically enhanced the production of BTEX and suppressed the formation of heavy species, including PAHs and catalyst coke.

Green Needle Coke Production from Pyrolysis Biocrude toward Bio-based Anode Material Manufacture: Biochar Fines Addition Effect as “Physical Template” on the Crystalline Order

Green Needle Coke Production from Pyrolysis Biocrude toward Bio-based Anode Material Manufacture: Biochar Fines Addition Effect as “Physical Template” on the Crystalline Order

Substantiation of thermophysical action over electrode paste to achieve an even structure of electrodes of needle coke for thermal furnaces

The aim was to develop a procedure for obtaining an electrode paste of needle coke in case of thermophysical action in the extruder circuit to produce graphitized carbon electrodes with the required structure and properties for thermal furnaces. To study the properties and composition of electrode pastes and electrodes, X-ray powder diffraction, electron microscopy, infrared spectroscopy, and calorimetry analysis were used. To evaluate the electrode behavior upon its heating in a melt, mathematical and statistical analysis was used. The data were processed using standard MS Office programs. Experiments with graphitized carbon materials were conducted in a calorimetric laboratory at the Scientific Center for Problems of Processing Mineral and Man-Made Resources, Department of Metallurgy, Saint Petersburg Mining University (Russia), using a developed proprietary prototype of the extruder. The conditions and technological parameters for processing electrode pastes were defined and substantiated (rate of extrusion and electrode paste flow, pressure, and heating rate within the defined temperature range to achieve stable structural indicators of electrodes). According to XRD data, the proposed method of thermophysical processing of an electrode paste via a special extruder within 550–620°C and a die pressure of 60–80 MPa provides an evenly directed structure of needle coke with an average needle thickness of 12–20 nm and a length of needle phases of 5–10 mm. The behavior of electrode samples was examined in the furnace melt within 1500–1700°C. The obtained stable levels of the thermal-expansion coefficient (0.3·10-6 °C-1) and specific electrical resistance (4.5–6.0 μmOhm·m) were manifested in reduced electrode sublimation, low losses of overall weight at the electrode end, decreased oxidation, and reduced damage on its side. The proposed electrode structure ensures stable heat and electrical conductivity, as well as high heat capacity, which levels are equivalent to those of imported electrodes and electrode pastes.

Utilization of Renewable Carbon in Electric Arc Furnace-Based Steel Production: Comparative Evaluation of Properties of Conventional and Non-Conventional Carbon-Bearing Sources

Conventional (anthracite, calcined petroleum coke, and coke) and non-conventional (biochar, and biocokes (3 wt.% torrefied wood, and 3 wt.% petroleum coke + 3 wt.% charcoal)) carbon-bearing sources have been studied for their use in electric arc furnace (EAF)-based steel production. Commonly, for the use of carbon sources in EAFs, one of the important properties is the content of fixed carbon, the release of volatiles as well as the elemental composition of inorganics. The properties of six carbon sources were analyzed by determining the proximate analysis, X-ray fluorescence analysis (XRF), coke reactivity index (CRI), and strength after reaction with CO2 (CSR), Brunauer–Emmett–Teller (BET) specific surface area and Barrett–Joyner–Halenda (BJH) pore size and volume analysis, ash chemical analysis, optical and scanning microscopy, Raman spectroscopy and X-ray diffraction (XRD) analysis. The results indicate biocoke as a promising option to replace conventional carbon-bearing sources. In the sample set, the fixed carbon, volatiles, and ash content of the biocokes were similar despite the total difference in additives. Additionally, the use of additives did not significantly affect the biocoke reactivity indices, but slightly decreased the strength after the reaction with CO2. Carbon-bearing sources have been characterized in terms of their structural properties. XRD analysis revealed that the amount of disordered carbon increased in the order: coke < calcined petroleum coke ~ biocoke (3 wt.% torrefied wood) < biocoke (3 wt.% petroleum coke + 3 wt.% charcoal) < biochar. The results obtained on the physical, chemical, and structural properties of carbon sources are the basis for further research on the behavior of slag foaming.

Distribution and ecological risk of polycyclic aromatic hydrocarbons in wastewater treatment plant sludge and sewer sediment from cities in Middle and Lower Yangtze River

The objective of this study was to conduct a comparative study of the distribution and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the sewage collection and treatment system of four cities located in the middle and lower reaches of the Yangtze River. The results revealed that the mean concentration of 16 ΣPAHs was higher in the sewer sediments (1489.45 ng·g−1) than in the sewage sludge (781.78 ng·g−1). PAH monomers were detected in all cases, with higher mean Pyr, Chr, BbF and BaP concentrations. PAHs with 4–6 rings were dominant in both sewage sludge and sewer sediment monomer PAHs. With the isomer ratio method and positive definite matrix factor (PMF) method, the results showed that the major sources of PAHs in sewage sludge were petroleum sources, coal tar, and coking activities, whereas PAHs in sewer sediments were primarily from wood combustion, automobile emissions, and diesel engine emissions. Of all the PAH monomers, BaP and DahA had the highest toxic equivalents, although their levels were not the highest. Based on the assessment of ΣPAHs, it was concluded that both sewage sludge and sewer sediments had medium ecological risk. The results of this study provide reference information for the control of PAHs in the wastewater collection and treatment system of the middle and lower reaches of the Yangtze River.

Impact of wheat straw and petroleum coke blending on combustion behavior of high ash coal

ABSTRACT This study reports the combustion behavior of coal, petroleum coke (PEC), wheat straw (WS), and their ternary blends to assess the impact of PEC and WS blending on coal combustion characteristics. Ignition temperature (TS), peak temperature (Tmax), burnout temperature (TB), performance indices, and combustion efficiency (η) were investigated to identify the influence of WS and PEC blending on coal combustion. Results infer that PEC has poor combustion characteristics and a higher gross calorific value of 8602 kcal/kg than coal and WS. For 10% PEC in blends, with the rise of WS from 10 to 30%, TS declined from 373 to 256°C, TB decreased from 510 to 509°C, signifying improvement in blend combustibility. At 400°C, η rose from 15.52 to 39.30% as WS increased in blends from 10 to 30%. For 15% PEC in the blend, activation energy reduced from 106.12 to 83.27 kJ/mol as WS increased from 10 to 25%. The synergistic effect is significant for higher biomass content in blends. Thermodynamics analysis inferred that PEC and coal combustion is turmoil than WS.

A novel process to recycle coal gasification fine slag by preparing Si-Fe-Al-Ca alloy

Maximizing the use of valuable components in coal gasification slag is of great significance for resource recovery and the environment due to the huge annual emission of coal gasification slag. This study successfully produced Si–Fe–Al–Ca alloy with a composition of 63.83 wt% Si, 19.73 wt% Fe, 7.09 wt% Al, 6.32 wt% Ca, 1.70 wt% Ti, 0.03 wt% P, 0.66 wt% Mn, 0.05 wt% Cr, 0.53 wt% C, and 0.06 wt% others through electric arc furnace smelting from mixed coal gasification fine slag. The alloy composition is close to the standard 65% ferrosilicon, which can be used in the deoxidation of the molten steel industry. Moreover, the alloy yield was increased from 20.53% to 67.78% by using the residual carbon of the coal gasification slag as the reductant directly instead of adding petroleum coke. The transformation of coal gasification fine slag during the smelting process and the formation mechanism of the alloy were studied and the carbothermal reduction mechanism of Al2O3 and CaO can be explained by the reduction and decomposition theory of carbides. The complex liquid phase of the reactant system and product system in the smelting process made the carbothermal reaction of Al2O3 and CaO easier to occur, but it also brought the problem that the reactions were not fully completed.

Preparation of High-Performance Zn-Based Catalysts Using Printing and Dyeing Wastewater and Petroleum Coke as a Carrier in Acetylene Acetoxylation

In this study, novel Zn catalysts were prepared by the wet impregnation method using printing and dyeing wastewater (PDW)-modified petroleum coke (petcoke) as a carrier, and they were applied to the acetylene acetoxylation. The pretreated petroleum coke has a high specific surface area which provides sufficient space for the loading of Zn. Calcination further increases catalyst activity, but when calcination temperatures exceed 1000 °C, a significant loss of Zn occurs, resulting in a dramatic decrease in catalyst activity. This enables the conversion of acetic acid up to 85%. X-ray photoelectron spectroscopy confirmed that a large amount of N is introduced into PC from PDW, which changes the electron transfer around Zn. Temperature-programmed desorption (TPD) analysis revealed that the nitrogen-doped Zn(OAc)2 catalyst enhanced the catalytic activity by modulating the intensity of the catalyzed adsorption of acetic acid and acetylene. This study provides a new way to reuse petroleum coke and printing and dyeing wastewater to support the sustainable development of the vinyl acetate industry.

Dynamic contribution and structural changes of carbon emissions in China's energy chemical industry with high-emission subsectors heterogeneity.

China's energy chemical industry accounts for about 12.01% of the national carbon emissions, while the heterogeneous carbon emission characteristics exhibited by the subsectors have not been reliably investigated. Based on the energy consumption data of the energy chemical industry subsectors in 30 Chinese provinces from 2006 to 2019, this study systematically identified the carbon emission contributions of high-emission subsectors, examined the evolutionary changes and correlation characteristics of carbon emissions from different perspectives, and further explored the carbon emission drivers. According to the survey, coal mining and washing (CMW) and petroleum processing, coking, and nuclear fuel processing (PCN) were high-emission sectors of the energy chemical industry, with annual emissions of more than 150 million tons, accounting for about 72.98% of the energy chemical industry. In addition, the number of high-emission areas in China's energy chemical industries has gradually increased, and the spatial disequilibrium of carbon emissions in industrial sectors has gradually deepened. The development of upstream industries had a strong correlation with carbon emissions, and the upstream industry sector still has not achieved carbon decoupling. The decomposition of the driving effects of carbon emissions showed that the economic output effect is the largest contributor to the growth of carbon emissions in the energy chemical industry, while energy restructuring and energy intensity reduction help reduce carbon emissions, but there is heterogeneity in the driving effects of subsectors.

Enhanced self-sintering mechanical strength of carbon blocks via removal of light molecular-weight compound in green petroleum coke

Self-sintering of green petroleum coke (GPC) offers a critical approach to prepare high performance carbon blocks owing to its remarkable homogeneity and high stability. However, the volatilization of small molecular fractions in green coke inevitably results in the formation of pores and cracks, thus severely limiting its commercial application. Herein, the GPC is divided into two soluble fractions with different molecular weight distribution, including dichloromethane-soluble (DCMS, 560.76 m/z) and dichloromethane-insoluble-toluene-soluble (DCMI-TS, 624.39 m/z), by sequential extraction with dichloromethane (CH2Cl2) and toluene based on processes of ultrasonic accompanying with continuous mechanical stirring for 4 h aging for 24 h and stirring at 130 ℃ for 4 h, respectively. All compounds extracted from GPC were further investigated via various characterizations, such as chromatography, ESR, elemental analysis, thermogravimetry, mass spectrometry, NMR, UV–Visible and FTIR, to verify their molecular weight distributions, chemical compositions, and reactivities. While DCMS contains long alkyl side chains, there are more naphthenic and oxygen-containing compounds and plasticizer species e.g. dibutyl phthalate in DCMI-TS. Thanks to the removal of volatile small molecular, when the solvent purified GPC were employed as precursor, the obtained carbon block (DCMI-C) demonstrates an apparent density of 1.48 g·cm−3, which is obviously higher than that of pristine GPC-C (1.34 g·cm−3). 1.7 times larger flexural strength, as well as 1.9 times higher compressive strength is found for DCMI-C compared to GPC-C, indicating that the DCM soluble compounds are the mainly reason for microcracks and pores generation. In addition, a much more compacted pore structure, as reflected in SEM images, is also observed in DCMI-C implying its remarkable mechanical intensity. Impressively, plasticizer species can also promote the self-sintering behavior of the green body where an enhanced mechanical property was achieved when 2 % dibutyl phthalate was added into DCMI mixtures.