Determination of Reasonable PCI Ratio of Blast Furnace Based on Grey Correlation Analysis and Petrographic Analysis

At present, the PCI ratio of a blast furnace is still regulated mainly by operator experience, because BF production data are high-dimensional, non-linear and strongly coupled. In this paper, for the key role of blast furnace (BF) pulverised coal injection (PCI) technology in the steel industry, grey correlation analysis (GCA) is introduced for the first time into the analysis of BF production data, and a method for determining the reasonable PCI rate of BF based on GCA and petrographic analysis is proposed. By collecting BF production data and applying GCA, the key factors affecting the PCI ratio of the BF and their correlation degrees were determined, and then the optimal PCI ratio interval of 175–181 kg/t was screened. In addition, petrographic analysis of BF dust at different PCI ratio stages was carried out to calculate the utilisation rate of PC, and the reasonableness of the optimal PCI ratio was verified by combining the comparison of key indexes and the analysis of combustibility of injection coal. With the determined optimal PCI ratio applied, the PCI ratio of the studied BF was increased from 167.0 kg/t to 180.75 kg/t, the coke ratio was reduced by 72.75 kg/t, and the utilisation rate of PC was increased from 79.44–89.03% to 92.71–96.86%. The results showed that this method can effectively optimise the PCI ratio, improve the utilisation rate of pulverised coal, reduce the production cost, and provide a scientific basis for the regulation of PCI ratio for steel enterprises.