Effect of pulverized coal residues on the blast furnace streaming conditions

Abstract

Despite measures to increase pulverised coal (PC) conversion, part of the injected PC leaves the raceway as char, particularly at high injection rates. The coke/PC replacement ratio and, consequently, the blast furnace (BF) operation efficiency depends on the consumption of char by reactions of secondary gasification and added burden. This contribution focuses on the change in streaming conditions in different BF zones when coal particles leave the raceway. To investigate this, a 2-D physical BF cold model was used. Tests were conducted after injecting various amounts of PC and under various gas flow rates. Particle movement and accumulation were examined by measuring the pressure drop at different positions in the model. To evaluate the effect of PC on the gas permeability in vertical and horizontal directions, calculations using the Darcy-Weisbach/Ergun equation were performed. The results will be used to improve CFD-modelling and the prediction of char behaviour in the BF.

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