Utilization of heat of slag is key technology for the reduction of CO₂ emission in steel industries. While hydrogen production is important for the society of aiming to the sustainable energy system, the green hydrogen must be produced for the actual CO₂ reduction.
In the present study, methane gas was injected into a molten slag and hydrogen was produced through the thermal decomposition reaction.
CH₄ = C + 2H₂
Kinetic analysis was performed using an graphite crucible both with empty and slag. The rate constants for the graphite crucible, k_G and the slag, k_S, were obtained separately.
The rate constants for graphite surface and slag surface, k_G and k_S, respectively, are as follows:
k_G / cm·s^–1 = 41.74 × exp(−51741 / RT) ± 0.05
k_S / cm·s^–1 = 4.053 × 10⁶ × exp(−190310 / RT) ± 0.05
Using the obtained rate constants, the increase of the area of reaction surface during the CH₄ injection was estimated.
It was found that the slow soaking of the injecting lance could be utilized for the heat of molten slag. In addition, the slag shape can be a powder type through the injection of CH₄.