Influence of coke properties and reactivity on coke fines behaviour in blast furnace and their emissions in off-gas dust
Conference
Gupta, SK, Sahajwalla, V, Saha-Chaudhury, N et al. (2004). Influence of coke properties and reactivity on coke fines behaviour in blast furnace and their emissions in off-gas dust
. 1 155-167.
Gupta, SK, Sahajwalla, V, Saha-Chaudhury, N et al. (2004). Influence of coke properties and reactivity on coke fines behaviour in blast furnace and their emissions in off-gas dust
. 1 155-167.
Increasing fuel injection rates is critical to improve economic and environmental efficiency of blast furnace ironmaking. At high fuel I injection rates, coke is believed to degrade and generate coke fines, which can influence the stability and efficiency of BF operation. A review is presented to highlight the influence of coke properties at high temperatures on coke fines generation. The main focus of the study is to investigate the influence of coke properties, particularly carbon structure, on coke gasification and coke fines. Three industrial cokes were reacted with 100% CO2 at 1100°C for 2 hours in a TGA furnace under typical gas and temperature profiles of the conventional CRI test. The same cokes were also graphitized in a horizontal furnace over a range of temperatures. Physical and chemical properties including carbon structure, coke minerals and their reaction products were investigated by XRD and FESEM, and related to CO2 reactivity. The study indicated that different cokes were graphitized to varying degrees which could influence fines generation. Furthermore, with increased levels of graphitization, the coke reactivity would decrease and slow its consumption through the solution loss reaction, both phenomena leading to increased coke fines in blast furnace dust. In this study, coke graphitization results could be related to coke reactivity with CO2 as well as coke fines reporting in off-gas dust emissions in blast furnaces. The study highlights that an integrated coke gasification index including coke graphitization effects to cover both aspects of fines generation and consumption is required for efficient management of coke fines in a blast furnace.
