A comprehensive investigation of the reaction behaviorial features of coke with different CRIs in the simulated cohesive zone of a blast furnace

Abstract

The reaction characteristics and mechanism of coke with different coke reactivity indices (CRIs) in the high-temperature zone of a blast furnace should be fully understood to correctly evaluate the coke quality and optimize ironmaking. In this work, low-CRI coke (coke A) and high-CRI coke (coke B) were charged into a thermogravimetric analyzer to separately study their microstructural changes, gasification characteristics, and reaction mechanism under simulated cohesive zone conditions in a blast furnace. The results show that both coke A and coke B underwent pyrolysis, polycondensation, and graphitization during the heat treatment. The pyrolysis, polycondensation, gasification speed, and dissolution speed rates of coke B were higher than those of coke A. Direct and indirect reduction between sinter and coke occurred in the cohesive zone and had different stages. The consumption rate of coke B was faster than that of coke A during the coke–sinter reduction. The carbon molecules of coke A must absorb more energy to break away from the skeleton than those of coke B.

From waste to energy storage: calcinating and carbonizing chicken eggshells into electrode materials for supercapacitors and lithium-ion batteries

“…Namely, EM 900 reached a higher degree of carbonization during pyrolysis at 900 °C, when the organic substrate was subjected to dehydrogenation (i) and condensation of aromatic structure (ii), whose C-C bonds possess high energy and hence, are stable. 24 Since processes (i) and (ii) proceed mostly above 600 °C, EM 600 has a less condensed chemical structure, with characterized by aryl compounds losing their side chains. 24 The overall residual mass of EM 600 and EM 900 at 1000 °C is high because it cannot combust in the nitrogen atmosphere.…”

“…24 Since processes (i) and (ii) proceed mostly above 600 °C, EM 600 has a less condensed chemical structure, with characterized by aryl compounds losing their side chains. 24 The overall residual mass of EM 600 and EM 900 at 1000 °C is high because it cannot combust in the nitrogen atmosphere. Over 80 wt% of solid residue indicates a high degree of carbonization and acceptable content of volatile organic matter in the obtained electrode materials.…”

Influence of Temperature and CO2 on High-Temperature Behavior and Microstructure of Metallurgical Coke

“…2 Specifically, in a cohesive zone and below, coke is affected by temperature, CO 2 , slag, iron, and gas flow. 3 As the only bulk material in the lower part of blast furnace, the high-temperature reaction behavior of coke in such a complex environment significantly affects the stability of the blast furnace. 4 Currently, it is generally considered that coke with low coke reactivity index (CRI) and high coke strength after reaction (CSR) exhibits better thermal performance.…”

“…Coke reacts differently from top to bottom in a blast furnace, and its behavior also changes . Specifically, in a cohesive zone and below, coke is affected by temperature, CO 2 , slag, iron, and gas flow . As the only bulk material in the lower part of blast furnace, the high-temperature reaction behavior of coke in such a complex environment significantly affects the stability of the blast furnace .…”