2019 Volume 59 Issue 4 Pages 643-654
For the decrease of CO2 emission from ironmaking field, it is important to clarify the behaviors of hydrogen in blast furnace (BF). However, when hydrogen content increased in BF, many reactions related to hydrogen occurred, and many complicated relationships among the reactions are generated. Especially, the behavior of water gas shift reaction (WGSR) is not understood correctly and the effects on the gasification reaction and the reduction reaction are not known at all.
In the present study, the interest was focused on the relationship between WGSR and coke gasification reaction. The WGSR was examined experimentally and kinetic analysis was performed with and without gasification reaction. The quantification of reaction rates was carried out by gas analysis method. Several kind of crucibles were developed for determining the respective reaction rates occurring in different position.
The rate equation of invers WGSR was decided aswhere the rate constant in the alumina crucible was obtained as
The single WGSR in alumina crucible is in an equilibrium state over 1573 K. Calculation of gasification reaction (KB, Boudouard reaction) in Zone 1 and Zone 1+2+3 were in excellent agreement with the observation under CO–CO2 system (without Hydrogen). When H2 was added to the reaction gases, Water gas reaction I (KW1) and II (KW2) in addition to KB were calculated separately and the total gasification reaction RCScal (=KB+KW1+KW2) was in good agreement with the observation. The relationship between the separated gasification reactions (KB, KW1 and KW2) and WGSR was discussed.