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00610 Coke quality requirements of European blast furnace engineers (joint EBFC paper)
77
Process
heating,
power and incineration
(energy applications in industry)
Coke in blast furnaces-use of coke 200 years ago 98/00609 in a blast furnace in Gliwice Sabela, W. Garbo-Energochemical-Ekol.. 1996, 41, (I), 25-2’). (In Polish) Gliwice coke was first used with blast-furnaces in central Europe. The prevalence of coke use in 18th century to melt iron and the technological effects of charcoal replacement by coke are discussed. Coke quality requirements of European blast fur98/00610 nace engineers (joint EBFC paper) Leonard, D. C. et al. Int. Cokemaking Congr. Proc., 3rd. 1996, I-10. The ever increasing levels of coal and oil injection are examples of the recent developments in blast furnace operation which have placed more emphasis on coke quality. A survey has been conducted of ironmaking plants across Europe to determine how companies are meeting these challenges and to find out the underlying philosophies behind coke property developments. Operators require a highly stabilized feed coke with a tight size distribution, high abrasion resistance and low CR1 and high CSR values. Low and consistent moisture, VM, ash, sulfur, alkali and phosphorus contents are also considered advantageous. Finally the paper demonstrates the importance of maintaining a homogeneous. consistent cake supply. Computer simulation for smelting treatment of 98100611 waste casting sand Chung, W. S. el al. Chawon Risaikn’ng, 1996, 5, (3), 24-30. (Korean) An energy and material balance concept was used to develop a computer simulation model for various smelting processes for melting waste casting sand. The model can predict coal, flux, and oxygen consumption and the volume and temperature of the off-gas. The major critical variables for the smelting process can be explained by using the analysis of energy and material balance. The most important variables for smelting process were found to be high post-combustion ratio. high heat transfer efficiency and refractory protection technology. For energy savings in this smelting process, raw materials selection proved important; the use of low volatile coal was particularly profitable. Continuous smelting of iron ores with refining of 98100612 pig iron melt to remove phosphorus and sulfur prior to steelmaking Floyd, J. M. and Warner, H. K. PCT Int. Appl. WO 97 23,656 (Cl. CZlCli 02); 3 Jul 1997, AU Appl. 9517,262, 22 Dee -1’995, 25 pp. The furnace for Fe ore smelting is described. It includes a reactor with molten pig iron and slag layers, and with two top submerged lances for injection of Oz, fuel and reductant into the molten slag with the increased reduction near the first lance and a lower reduction at the second lance. The fuel and reductant are powdered coal, fuel oil, and/or natural gas. The lances are spaced with the first lance closer to a slag-tapping zone for S removal and Fe0 reduction in the slag, and the second near the pig-iron tapping zone for effective P removal. Residual fuel gases as well as coal fines are removed in the furnace by secondary combustion with injected Oz. Current status of coal injection in North America 98/00613 Ranade, M. G. ef al. Int. Ironmaking Congr. Proc., 3rd, 1996, 82-92. Coal injection initially began as a routine practice at Armco (now AK) Steel’s Ashland, KY, plant in 1963. However, it was not adopted at other North American steel plants, until February 1993 when coal injection was commissioned on 13 more blast furnaces in North America in the following three years. Five different coal injection system designs were in use at six coal preparation plants as of January 1996 with a combined annual coal grinding capacity of 4.3 million Mg. In just two years, coal injection rates in excess of 150 kg/t HM and coke rates below 340 kg/Mg HM were reached. North American ironmakers have developed innovative practices to simultaneously achieve high productivity and low coke consumption by using high-02 enrichment and multiple fuel injection through tuyeres. Development of a new scrap melting process based 98/00614 on massive coal and plastics injection Ariyama, T. et al. ht. Cokemaking Congr. Proc., 3rd, 1996, 314-321. A new, energy efficient hot metal production process has been developed by NKK based on a shaft furnace that can melt scrap in an oxygen burner using pulverized coal and waste plastics as fuels. To confirm the characteristics of the new process, the continuous test operation was conducted for about one and half months, using the 2m’ inner volume shaft furnace. NKK’s originally developed oxygen burner enabled higher injection of pulverized coal and plastics up to 300 kg/t in the tests, succeeding in a stable operation of maximum production rate of 14tidm’. Effect of chars on primary slag and hot metal of the 98100615 blast furnace. Phase I Ponghis, N. and Danloy, G. Comm. Eur. Communities, [Rep.] EUR, 1997, 64 pp. (In French) To achieve high coal injection rates, this research aims at quantifying the ability of chars to react with primary slag and metal issued from the cohesive zone. A method was developed to produce and collect different types of chars under various operating conditions similar to those in the blast furnace, particularly with high coal injection rates. A laboratory test was developed to quantify the reactivity of chars with the bosh slag, The chars reactivity differs from those of coke with similar size distributions; it depends on the operating conditions. Under pulverized state, chars only
52
Fuel and Energy Abstracts
January 1998
carburize the metal a little. When agglomerated with IO% bentonite, the same materials carburize the metal up until near saturation, similar to a coke lump. 98/00616 Effect of injected coal properties on performance of the blast furnace Hutny, W. P. et al. DGMK Tagungshrr., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1315-1318. The influence of coal combustibilitv. erindability, and cooling, as well as coke replacement characteristics on the performance of blast furnaces is explored. The cooling effect on the blast furnace combustion zone (raceway) is caused mostly by endothermic reactions between the fuel combustion products and hot coke. By adjusting the type and/or amount of coal, the extent of cooling of the raceway can be altered. because this permits a better control of RAFT and thermal regime of the furnace. Analysis of simulated data revealed that coal parameters, such as calorific value and ash content, can be used to predict coke replacement ratios. Coals of high calorific value can achieve high replacement ratios. I
_
Energy-efficient production of chilled water in 98/00617 industry Albassam, E. et al. EnerD, 1997, 22, (IZ), 1183-l 18X. A study of current practices for operation of a water-chilling plant (WCP) in the cement product industry in Kuwait and they were evaluated under different load conditions. Experimental results and weather data are used to demonstrate deficiencies in the present design. An analysis has been conducted to arrive at the optimum use of a cooling tower (CT) and chillers for year-round application. A significantly larger cooling tower is recommended for technical and economic viability. The case study may serve as a guide for optimizing the design and operation of other types of water-chilling plants. 98lOO618 The engineering of a cyclone converter furnace (CCF) plant Meiier, H. K. A. ef a/. Int. C‘okemakirx Corlgr. Proc.. 3x/, lY96, 299-303. As &I alternative to the blast furnace pricess. the CCF ironmaking process. using fine ores and coal directly, can be implemented. Coking and agglomeration processes are not required. The principles of the CCF process were demonstrated in large-scale pilot plant research programmes. The paper studies the feasibility of the CCF installation, particularly with respect to the lifetime of the containment vessel. The construction of a largely water cooled CCF reactor is technically feasible. 98/00619 Heterogeneous gas-solid reactions. Ill. Industrial significance and use Skala, D. and Kuzmanovic, B. Hem. frtd., 1997, 5 I, (7-8). 300-3 I?. (In Serbian) This paper presents the industrial application and importance of hetcrogeneous chemical reactions between a gas and a solid reactant. The extraction of metal from ores, the combustion of solid fuel, coal gasification, the burning of solid waste, desulfurization of polluting gases and catalyst manufacture are some examples of processes which include the gas-solid heterogeneous reaction. High temperature superconductor synthesis and the synthesis of ceramic fibres are some examples of recently developed gas-solid reactions. In this paper, coal gasification, the burning of solid waste and synthesis performed at a high temperature arc analysed. The mechanism and mathematical models of the coal gasification reaction are shown. The most common equipment and plants for these processes are also described. High temperature superconductor synthesis is a modern process. and is still under laboratory research. The chemical reactions in which the superconducting material is produced are mostly gas-solid reactions. 98100620 The importance of radial gas flow for the adjustment of coal injection rate Kowalski, H. et al. ht. Ironmaking Congr. Proc., 3~1, 1996. 99-108. Reduced coke layers in the blast furnace and increased coke charging at the furnace centre result from the increased coal rates. Consequently, the gas flow at the blast furnace periphery becomes much more significant, especially in the case of large blast furnaces. ETA CO holding zones form at the blast furnace periphery, meaning an inadequate amount of prereduced burden reaches the liquid area, the area before the tuyeres is considerably undercooled, and the coal injected can no longer gasify. With an increased central gas flow the quantities of dust in the centre of the furnace rise but the C,,,,, contents in the dust at the blast furnace centre drop, and rise considerably with a weaker central gas flow. Also the C,,,,,, content in dust at the periphery increases with a weaker central gas flow. On the whole the injected coal still retains its volatile components when leaving the tuyere, but releases them when pushed by the kinetic energy of the blast to the furnace centre. These become apparent in an Hz concentration in the gas at the centre of the blast furnace, which is excessive when measured in terms of ETA CO. The extent of the H2 concentration at the furnace centre is therefore related to the C,,,.,, content of the dust. The peripheral gas flow above the furnace height can be controlled by means of the level of the central gas flow. With a weaker central gas flow, the ETA CO 2.2 m above tuyere level is well above 3lO’r, so that it is not yet possible to reduce the wustite just above tuyere level. meaning insufficient pre-reduced burden reaches the liquid area. This results in insufficient liquid gasification of the coal.
Process
heating,
power and incineration
(energy applications in industry)
Coke in blast furnaces-use of coke 200 years ago 98/00609 in a blast furnace in Gliwice Sabela, W. Garbo-Energochemical-Ekol.. 1996, 41, (I), 25-2’). (In Polish) Gliwice coke was first used with blast-furnaces in central Europe. The prevalence of coke use in 18th century to melt iron and the technological effects of charcoal replacement by coke are discussed. Coke quality requirements of European blast fur98/00610 nace engineers (joint EBFC paper) Leonard, D. C. et al. Int. Cokemaking Congr. Proc., 3rd. 1996, I-10. The ever increasing levels of coal and oil injection are examples of the recent developments in blast furnace operation which have placed more emphasis on coke quality. A survey has been conducted of ironmaking plants across Europe to determine how companies are meeting these challenges and to find out the underlying philosophies behind coke property developments. Operators require a highly stabilized feed coke with a tight size distribution, high abrasion resistance and low CR1 and high CSR values. Low and consistent moisture, VM, ash, sulfur, alkali and phosphorus contents are also considered advantageous. Finally the paper demonstrates the importance of maintaining a homogeneous. consistent cake supply. Computer simulation for smelting treatment of 98100611 waste casting sand Chung, W. S. el al. Chawon Risaikn’ng, 1996, 5, (3), 24-30. (Korean) An energy and material balance concept was used to develop a computer simulation model for various smelting processes for melting waste casting sand. The model can predict coal, flux, and oxygen consumption and the volume and temperature of the off-gas. The major critical variables for the smelting process can be explained by using the analysis of energy and material balance. The most important variables for smelting process were found to be high post-combustion ratio. high heat transfer efficiency and refractory protection technology. For energy savings in this smelting process, raw materials selection proved important; the use of low volatile coal was particularly profitable. Continuous smelting of iron ores with refining of 98100612 pig iron melt to remove phosphorus and sulfur prior to steelmaking Floyd, J. M. and Warner, H. K. PCT Int. Appl. WO 97 23,656 (Cl. CZlCli 02); 3 Jul 1997, AU Appl. 9517,262, 22 Dee -1’995, 25 pp. The furnace for Fe ore smelting is described. It includes a reactor with molten pig iron and slag layers, and with two top submerged lances for injection of Oz, fuel and reductant into the molten slag with the increased reduction near the first lance and a lower reduction at the second lance. The fuel and reductant are powdered coal, fuel oil, and/or natural gas. The lances are spaced with the first lance closer to a slag-tapping zone for S removal and Fe0 reduction in the slag, and the second near the pig-iron tapping zone for effective P removal. Residual fuel gases as well as coal fines are removed in the furnace by secondary combustion with injected Oz. Current status of coal injection in North America 98/00613 Ranade, M. G. ef al. Int. Ironmaking Congr. Proc., 3rd, 1996, 82-92. Coal injection initially began as a routine practice at Armco (now AK) Steel’s Ashland, KY, plant in 1963. However, it was not adopted at other North American steel plants, until February 1993 when coal injection was commissioned on 13 more blast furnaces in North America in the following three years. Five different coal injection system designs were in use at six coal preparation plants as of January 1996 with a combined annual coal grinding capacity of 4.3 million Mg. In just two years, coal injection rates in excess of 150 kg/t HM and coke rates below 340 kg/Mg HM were reached. North American ironmakers have developed innovative practices to simultaneously achieve high productivity and low coke consumption by using high-02 enrichment and multiple fuel injection through tuyeres. Development of a new scrap melting process based 98/00614 on massive coal and plastics injection Ariyama, T. et al. ht. Cokemaking Congr. Proc., 3rd, 1996, 314-321. A new, energy efficient hot metal production process has been developed by NKK based on a shaft furnace that can melt scrap in an oxygen burner using pulverized coal and waste plastics as fuels. To confirm the characteristics of the new process, the continuous test operation was conducted for about one and half months, using the 2m’ inner volume shaft furnace. NKK’s originally developed oxygen burner enabled higher injection of pulverized coal and plastics up to 300 kg/t in the tests, succeeding in a stable operation of maximum production rate of 14tidm’. Effect of chars on primary slag and hot metal of the 98100615 blast furnace. Phase I Ponghis, N. and Danloy, G. Comm. Eur. Communities, [Rep.] EUR, 1997, 64 pp. (In French) To achieve high coal injection rates, this research aims at quantifying the ability of chars to react with primary slag and metal issued from the cohesive zone. A method was developed to produce and collect different types of chars under various operating conditions similar to those in the blast furnace, particularly with high coal injection rates. A laboratory test was developed to quantify the reactivity of chars with the bosh slag, The chars reactivity differs from those of coke with similar size distributions; it depends on the operating conditions. Under pulverized state, chars only
52
Fuel and Energy Abstracts
January 1998
carburize the metal a little. When agglomerated with IO% bentonite, the same materials carburize the metal up until near saturation, similar to a coke lump. 98/00616 Effect of injected coal properties on performance of the blast furnace Hutny, W. P. et al. DGMK Tagungshrr., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1315-1318. The influence of coal combustibilitv. erindability, and cooling, as well as coke replacement characteristics on the performance of blast furnaces is explored. The cooling effect on the blast furnace combustion zone (raceway) is caused mostly by endothermic reactions between the fuel combustion products and hot coke. By adjusting the type and/or amount of coal, the extent of cooling of the raceway can be altered. because this permits a better control of RAFT and thermal regime of the furnace. Analysis of simulated data revealed that coal parameters, such as calorific value and ash content, can be used to predict coke replacement ratios. Coals of high calorific value can achieve high replacement ratios. I
_
Energy-efficient production of chilled water in 98/00617 industry Albassam, E. et al. EnerD, 1997, 22, (IZ), 1183-l 18X. A study of current practices for operation of a water-chilling plant (WCP) in the cement product industry in Kuwait and they were evaluated under different load conditions. Experimental results and weather data are used to demonstrate deficiencies in the present design. An analysis has been conducted to arrive at the optimum use of a cooling tower (CT) and chillers for year-round application. A significantly larger cooling tower is recommended for technical and economic viability. The case study may serve as a guide for optimizing the design and operation of other types of water-chilling plants. 98lOO618 The engineering of a cyclone converter furnace (CCF) plant Meiier, H. K. A. ef a/. Int. C‘okemakirx Corlgr. Proc.. 3x/, lY96, 299-303. As &I alternative to the blast furnace pricess. the CCF ironmaking process. using fine ores and coal directly, can be implemented. Coking and agglomeration processes are not required. The principles of the CCF process were demonstrated in large-scale pilot plant research programmes. The paper studies the feasibility of the CCF installation, particularly with respect to the lifetime of the containment vessel. The construction of a largely water cooled CCF reactor is technically feasible. 98/00619 Heterogeneous gas-solid reactions. Ill. Industrial significance and use Skala, D. and Kuzmanovic, B. Hem. frtd., 1997, 5 I, (7-8). 300-3 I?. (In Serbian) This paper presents the industrial application and importance of hetcrogeneous chemical reactions between a gas and a solid reactant. The extraction of metal from ores, the combustion of solid fuel, coal gasification, the burning of solid waste, desulfurization of polluting gases and catalyst manufacture are some examples of processes which include the gas-solid heterogeneous reaction. High temperature superconductor synthesis and the synthesis of ceramic fibres are some examples of recently developed gas-solid reactions. In this paper, coal gasification, the burning of solid waste and synthesis performed at a high temperature arc analysed. The mechanism and mathematical models of the coal gasification reaction are shown. The most common equipment and plants for these processes are also described. High temperature superconductor synthesis is a modern process. and is still under laboratory research. The chemical reactions in which the superconducting material is produced are mostly gas-solid reactions. 98100620 The importance of radial gas flow for the adjustment of coal injection rate Kowalski, H. et al. ht. Ironmaking Congr. Proc., 3~1, 1996. 99-108. Reduced coke layers in the blast furnace and increased coke charging at the furnace centre result from the increased coal rates. Consequently, the gas flow at the blast furnace periphery becomes much more significant, especially in the case of large blast furnaces. ETA CO holding zones form at the blast furnace periphery, meaning an inadequate amount of prereduced burden reaches the liquid area, the area before the tuyeres is considerably undercooled, and the coal injected can no longer gasify. With an increased central gas flow the quantities of dust in the centre of the furnace rise but the C,,,,, contents in the dust at the blast furnace centre drop, and rise considerably with a weaker central gas flow. Also the C,,,,,, content in dust at the periphery increases with a weaker central gas flow. On the whole the injected coal still retains its volatile components when leaving the tuyere, but releases them when pushed by the kinetic energy of the blast to the furnace centre. These become apparent in an Hz concentration in the gas at the centre of the blast furnace, which is excessive when measured in terms of ETA CO. The extent of the H2 concentration at the furnace centre is therefore related to the C,,,.,, content of the dust. The peripheral gas flow above the furnace height can be controlled by means of the level of the central gas flow. With a weaker central gas flow, the ETA CO 2.2 m above tuyere level is well above 3lO’r, so that it is not yet possible to reduce the wustite just above tuyere level. meaning insufficient pre-reduced burden reaches the liquid area. This results in insufficient liquid gasification of the coal.