Reaction Behavior of Ca-loaded Highly Reactive Coke

Abstract

Usage of highly reactive coke in order to decrease the thermal reserve zone temperature in a blast furnace is considered promising to increase the reaction efficiency in the blast furnace and to decrease the reducing agent rate. In order to develop a new method to produce highly reactive coke by adding a Ca catalyst other than Ca-rich coal, in this paper, firstly the effects of Ca compounds pre-addition to coal on coke qualities were investigated. It was shown that carbonizing the mixture of coal and Ca compounds (CaO, CaCO3) greatly increased coke reactivity and that it was possible to produce Ca-loaded highly reactive coke with high coke strength by adding 3% of Ca compounds under such conditions as high strength coke was produced. Furthermore, the reaction behavior of Ca-loaded highly reactive coke when mixed with conventional coke in the presence of an alkali was investigated. It was shown that when a mixture of Ca-loaded highly reactive coke and conventional coke was heated in a reaction gas, Ca-loaded coke selectively and preferentially reacted. It was also confirmed that Ca acted as catalyst in the existence of K. This shows that the reactivity of Ca-loaded coke is higher than that of conventional coke in an actual blast furnace whereby coke reactivity is promoted by condensed alkali vapor.

Reduced Carbon Consumption and CO2 Emission at the Blast Furnace by Use of Briquettes Containing Torrefied Sawdust

“…TRZT can be lowered by charging of briquettes produced from in-plant fines as these contain iron oxide and carbon or by using Ferrocoke in which endothermic direct reduction of FeO with carbon will reduce the temperature [5]. Another option is charging of reactive [6][7][8][9][10] or activated coke that reacts readily with CO 2 producing CO according to the Boudouard reaction. Coke activated with slurries of magnetite and hydrated lime was charged as nut coke in the ferrous layers during operational trials in the LKAB EBF [6][7][8].…”

Transformation of Coke Carbon Textures and Minerals during Gasification Investigated by SEM/EDS

“…Due to the close relationship between coke carbon and mineral matter, coke minerals could affect the strength and reactivity of coke in many ways such as the formation of cracks and weak spots in the coke matrix and the catalyzing reactions by catalytic mineral phases. − The production and utilization of highly reactive catalyst-loaded coke to increase the reaction efficiency and decrease the reducing agent rate in the BF have been extensively reported. − Additionally, the BF environment such as high temperatures and recirculating alkalis could also affect coke gasification. Therefore, it is crucial to gain a better understanding of the coke minerals and their interactions with the coke carbon matrix under BF conditions.…”

Impact of Potassium on Gasification Reaction and Post-Reaction Strength of Ferro-coke

“…Nomura et al [17][18][19] studied gasification reaction and post-reaction strength of catalyst-loaded ferro-coke. In this paper, focused on ferro-coke, the thermogravimetry (TG) technique was applied to the measurement of the starting gasification temperature of coke and to the analysis of reaction kinetics, and the Tablets Coke Method was applied to the measurement of the reactivity and the post-reaction strength of coke.…”