Modeling of biochar composite briquette reaction in blast furnace

In this study, the reaction behavior of biochar composite briquette (BCB) in an actual blast furnace (BF) was investigated by modeling. The prepared BCB contained 11.1 wt% carbon, 72.7 wt% magnetite, 11.25 wt% wustite, 0.77 wt% metallic iron, and 4.67 wt% gangue. A reaction model for single BCB in BF was developed and validated using the results of four isothermal scenarios. Then, the reaction behavior of BCB along the mid-radial solid flowing path in a 2500 m(3) BF was analyzed. The results show that the developed model was reliable. In the BF, reactions of BCB mainly included three stages and they were reduction by BF gas (473-853 K), reduction by BF gas, partial self-reduction (853-953 K), and full self-reduction (953-1150 K). The simulation results also indicated that, when a large amount of BCB was charged into BF, in the temperature range with BCB self-reduction, the local gas utilisation of BF gas was increased; and the BCB self-reduction had a positive influence on lowering the temperature level of thermal reserve zone. Modelisation de la reaction des briquettes composites de biocharbon dans un haut fourneau Dans cette recherche, on a etudie par modelisation le comportement reactionnel de briquettes composites de biocharbon (BCB) dans le haut fourneau. La BCB preparee contenait 11.1% en poids de carbone, 72.7% en poids de magnetite, 11.25% en poids de wustite, 0.77% en poids de fer metallique et 4.67% en poids de gangue. On a developpe un modele de reaction pour une seule BCB dans le haut fourneau et on l'a valide a l'aide des resultats d'essai de reaction isotherme des echantillons de BCB prepares. On a ensuite analyse par modelisation la reaction de la BCB le long du chemin d'ecoulement solide median dans un haut fourneau de 2500 m(3). Les resultats ont montre que le modele developpe etait fiable. Dans le haut fourneau, la BCB a subi une auto-reduction complete et a joue le role d'intensification de la reduction du frittage et de suppression de la gazeification du coke dans la gamme de temperature de 950 K a 1150 K. L'oxyde de fer dans la BCB etait reduit beaucoup plus rapidement pres de la surface que pres du centre dans la gamme de temperature de 950 K a 1150 K. Cependant, le biocharbon dans la BCB a ete gazeifie de maniere approximativement uniforme dans la direction radiale a mesure que la temperature augmentait.

Automated summary

This study investigated the reaction behavior of biochar composite briquette (BCB) in an actual blast furnace (BF) by modeling. The results show that the reactions of BCB mainly included three stages and the self-reduction of BCB had a positive influence on lowering the temperature level of thermal reserve zone.