| 2024 |
Lomas H, Roest R, Sakurovs R, Edwards A, Wu H, Jiang Z, Brooks B, Mahoney MR, Tahmasebi A, 'Influence of elevated temperature and gas atmosphere on coke abrasion resistance. Part two: Blast furnace cokes', FUEL, 371 (2024) [C1]
In this second in a series of two papers, the results of tribological testing of surfaces of coke samples retrieved from an operating blast furnace were compared with t... [more]
In this second in a series of two papers, the results of tribological testing of surfaces of coke samples retrieved from an operating blast furnace were compared with those of the corresponding feed coke, to assess the impact of the conditions in the blast furnace on the abrasion resistance of coke. Tribological tests were carried out at temperatures of up to 950 °C under a controlled inert (argon) or reactive (CO2) atmosphere. Coke wear characteristics were quantified via (i) analysis of the coefficient of friction (COF) during tribological testing, and (ii) the application of microscopy and imaging techniques to the abraded specimens. The blast furnace coke sample was from the underside of the cohesive zone and is referred to as bosh coke in this paper. A near-matched feed coke was also examined. Under ambient testing conditions, the bosh coke had a lower abrasion resistance than the unreacted feed coke samples, indicating that the conditions coke is subjected to during its descent in the blast furnace effectively reduces its resistance to abrasion. Increasing the measurement temperature to 950 °C lowered the abrasion resistance of both the reactive maceral derived components (RMDC) and the inertinite maceral derived components (IMDC) in both samples. The bosh coke RMDC showed more severe damage than the IMDC, using a subjective damage severity scale. The difference in damage severity between these two phases in the bosh coke was reduced as the severity of the tribological testing conditions increased from ambient to elevated temperature (950 °C) to a reactive CO2 environment. Feed coke samples that had been pre-reacted with CO2 displayed a mean COF over time trend that was similar to that obtained from the bosh coke samples. During in-situ testing in a CO2 environment, tribo-chemical wear of the IMDC was detected, due to the surface of the IMDC reacting with the CO2 in the atmosphere. The observed tribo-chemical wear was due to the indenter and the coke surface rubbing against each other in this CO2 environment, resulting in the continuous formation and removal of reaction products. Similar trends in COF over time were observed for the bosh and feed cokes during in-situ reaction with CO2. The substantial decrease in abrasion resistance in coke at high temperature suggests that abrasion may be a more significant degradation pathway for coke in the blast furnace than hitherto expected.
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Open Research Newcastle |
| 2024 |
Lomas H, Roest R, Sakurovs R, Wu H, Jiang Z, Rish SK, Brooks B, Hill T, Anderson A, Edwards A, Mahoney MR, Tahmasebi A, 'Influence of elevated temperature and gas atmosphere on coke abrasion resistance. Part one: Pilot oven cokes', FUEL, 356 (2024) [C1]
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Open Research Newcastle |
| 2023 |
Brooks B, Rish SK, Lomas H, Jayasekara A, Tahmasebi A, 'Advances in low carbon cokemaking-Influence of alternative raw materials and coal properties on coke quality', JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS, 173 (2023) [C1]
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Open Research Newcastle |
| 2023 |
Lee S, Brooks B, Chen Y, Hockings K, Yu J, Tahmasebi A, 'Mechanistic study of plastic layer permeability during coking of Australian metallurgical coals', FUEL, 331 (2023) [C1]
The plastic layer permeability of five Australian coals was analyzed using two permeability measurement apparatuses operating under isothermal and thermal gradient indu... [more]
The plastic layer permeability of five Australian coals was analyzed using two permeability measurement apparatuses operating under isothermal and thermal gradient induced coking conditions. In addition, the microstructure transitions across the plastic layers of the coals were analyzed using Synchrotron micro-CT. The permeability results and pore structure parameters derived from those analyses were correlated to better understand the mechanisms of plastic layer permeability. The high-rank coking coal with low fluidity showed a low plastic layer permeability over a wide temperature range and the generation of high internal gas pressure (IGP). Among all samples tested, the high-rank coal formed an intermediate plastic layer with the lowest number of isolated pores and the smallest size of open pores. This suggests that the lower deformability of the pore structures brought about by the low fluidity prevented additional pore growth and thus hindered pore interconnectivity. Additionally, it is possible that the low permeability in the resolidfied layer lends to pore expansion due to the difficulty of volatile release, evidenced by the larger volume of open pores within a larger size range of 50¿100 µm. It appears that the intermediate plastic layer with less interconnectivity solidified into the expanded open pore structures in the resolidified layer through the driver of high IGP, thus contributing to the low permeability. In addition, the formation of the low permeable barrier seemed to redirect the volatiles evolved from the plastic layer toward the loose coal side, which dramatically reduced the temperature range of the plastic layer during its progression from the wall to the center. These results suggest that the plastic layer permeability is influenced by several factors which affect mass transfer in the plastic layer. As such, various approaches were used in this study to observe phenomena of plastic layer permeability.
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Open Research Newcastle |
| 2023 |
Jayasekara AS, Brooks B, Steel K, Koshy P, Hockings K, Tahmasebi A, 'Microalgae blending for sustainable metallurgical coke production - Impacts on coking behaviour and coke quality', FUEL, 344 (2023) [C1]
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Open Research Newcastle |
