Papers by Keyword: Coke

Abstract: The article is devoted to the study of destructibility of the annealed anode paste of different composition in the CO₂ current. It is shown that the destructibility of CO₂ current of petroleum coke is much less than that of pitch coke. The comparison of the qualitative characteristics of the anode paste on the basis of pitch coke and petroleum coke revealed the advantage of petroleum coke, due to its low sodium content. The average destructibility of the anode paste on the basis of different grades of cokes in the CO₂ current is determined. The conducted semi-industrial tests were in good agreement with the laboratory studies.

Abstract: In this research, the carbothermal reduction of Langkawi ilmenite ore, FeTiO₃ had been conducted by using coke as carbon reductant. All samples were grinded into size of ≤ 63 µm and pelletized using 2.5 g mixture of ilmenite ore with coke based on C/O molar ratio of 1:3 (carbon to reducible oxygen). The carbothermal reduction was conducted in a horizontal tube furnace using 0.1 L/min of argon gas flow at temperature of 1200°C. The ultimate and proximate analysis of carbon reductant was investigated using carbon, hydrogen, oxygen, nitrogen and sulfur (CHONS) analyzer. The phase evolutions and chemical composition analysis was conducted using X-ray diffraction (XRD) and X-ray fluorescence (XRF) for raw ilmenite and reduced ilmenite with coke, respectively. The reduction time was set with 2, 3 and 4 hours to understand the phase evolutions. It was found that Langkawi ilmenite ore contained mainly higher TiO₂ and hematite, Fe₂O₃ where the phases of FeTiO₃ and titanomagnetite, (Fe₂TiO₄-Fe₃O₄) were detected using XRD. The phase of FeTiO₃ evolved into the production of Fe, FeO, TiC, TiO₂ and Fe₃C when increased the reduction time from 2 to 4 hours. The amount of Fe₂O₃ production was decreased from 59.16 to 47.02 wt%, while higher value of TiO₂ was obtained, increasing from 25.2 to 29.1 wt% due to the reduction of TiO₂ to Ti₃O₅ as the reduction time increased. TiC content is also detected when the reduction time increased by reducing TiC_xO_y into TiC.

Abstract: Results of the design analysis carried out using computer software are presented for boundary data complying with the currently operating state-of-the-art arc steel furnace. Flow of natural gas combustion products and oxygen are reviewed for the radial and tangential burner arrangement in the working space between the wall and the electrodes. Location of high temperature fields is determined and the expected heat transfer to the charge materials through the active surface participating in heat exchange is evaluated. Precipitation degree is determined for the dust participating in scull generation on a wall water-cooled surface and significant reduction of dust effect on electrodes.

Abstract: The article is devoted to the study of the impact of technological features of the anode paste production on one of the technical-and-economic indices – its consumption. It is shown that the prior thermal preparation significantly affects the quality characteristics of pitch and petroleum cokes. The comparison of pitches of foreign and homeland producers revealed the advantage of the last because of their small ash content and the lowered content of sodium. Granulometric composition of the dry mix is determined on the basis of different coke brands. They are close to the concentrations of fractions regulated by the technology of production of the anode paste. The conducted semi-industrial tests were in accordance with the laboratory studies and confirmed the fact of reducing the consumption of the anode paste when using the petroleum coke as a filler.

Abstract: The principal coke modification possibility with butyl potassium xanthate was revealed. It was shown that the modified coke exhibits sorption properties with respect to nickel ions compared to untreated coke, traditionally used for melting. The influence degree of various factors on the sorption capacity of the modified coke was established.

Abstract: Generally, the conventional carbon sources such coke/coal are used in EAF steelmaking attributed the highest growth rate in energy consumption. A substitute routes striving to improve energy efficiency by providing auxiliary sources is essential. The unique features such high carbon content, surface area, porosity and low sulphur was available in agricultural waste clearly have the potential to be used as reducing agent in steelmaking process. The present study investigated the reduction behavior of EAF slag and production of metallic iron by reduction process. The carbon materials, coke and palm char (pyrolyzed via chemical activation) were used as reducing agent composite with EAF slag respectively. The reduction reaction was conducted in horizontal tube furnace at different reduction temperatures (1250°C, 1350°C, 1450°C and 1550°C) under argon gas (flow rate 0.01L/min) within 20 minutes. The reduced sample was examined by X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) to understand the reduction behavior of both composite samples. Palm char showed more efficient due to improvement in degree of FeO reduction which was 57.72% compared to coke, 26.72%. The phase movement from iron oxide to iron was influenced by the reduction temperatures. XRD pattern revealed that the metallic iron was initiating appeared at temperature 1250°C and completely reduced at temperature of 1550°C . Predominant peak of metallic iron and the other oxides was clarified by EDS spectra. This study found that palm char has viability to be used as carbon sources in steelmaking applications.

Abstract: Electric arc furnace steelmakers are finding that dealing with the dust is increasingly difficult. Stockpiling this dust on site, recycling or sending offsite for disposal all entail considerable difficulties and costs. Succesful recycle of the valuable metals (iron, zinc) present in electric arc furnace dust will result in resource conservation while simultanuously reducing the disposal problem. In this research, carbothermic reduction of electric arc furnace dust using coke has been performed to observe the reduction ability and volatilization rate of zinc. Several properties of the dust were determined using chemical analysis, differential scanning calorimetry (DSC), X-ray diffraction (XRD), etc. It was found that the dust contained 24 %mass of iron, 14 %mass of zinc which stayed in oxide form. Experimental results shown that rates of the volatilization zinc in the dust were high, e.g. 96.45% at 1100°C. The activation energy of the reduction was calculated to be 210.63 kJ/mol in temperature range of 900 to 1100°C. Futher study on effective collection of iron and volatile zinc oxide must be carried out to obtain a suitble procedure of recycle of the electric arc furnace dust.

Abstract: Coke on Zn/Hβ catalyst in ethanol to propylene was studied in continuous-flow fixed-bed reactor. The physicochemical properties of these fresh and used catalysts were characterized by NH₃-TPD, N₂ isothermal adsorption-desorption and TPO. These results showed that the medium and strong acid sites might be responsible for the production of coke and coke mainly deposited on external surface and microporous mouth. In addition, the coke might be consisted of soft coke and hard coke.

Abstract: The catalytic performance on HZSM-5/SAPO-34 catalyst in ethanol to propylene was tested in continuous-flow fixed-bed reactor. Coke on HZSM-5/SAPO-34 catalyst for ethanol to propylene was studied by O₂-TPO, N₂ isothermal adsorption–desorption and NH₃-TPD.The result showed that the strong and medium acid sites were the active centers of coke deposition; Coke mainly deposited in mesoporous and some coke blocked microporous orifice; In the initial stage of reaction, the high yield of propylene may be benefited from coke deposition, which adjusted the acidity and structure of HZSM-5/SAPO-34.

Abstract: Coal extraction produces large amounts of wastewater containing coal powders, which could be used to produce coke. In this case, binder materials should be used to allow compression capacity to the mixture. This work aims to study the effect of binder addition in mixtures of coals containing different contents of coal powders to obtain coke. Compositions containing different amounts of coal powders were prepared by varying the nature and the contents of the binders to allow the pressing of powders. Study of the thermal behavior of these compositions was performed. The composition that showed the best results was then homogenized, pressed and heat treated. The final composition showed FSI about 4.5 and compressive strength of 5 MPa, demonstrating high potential for coke production from coal powder.