Effect of coal fragmentation on PCI combustion zone in blast furnace

Abstract

Pulverized Coal Injection (PCI) is one of the most effective technologies for reducing coke consumption in blast furnaces. Its main role is as the heating source and for the generation of CO gas. Generally, PCI coal is a high-rank coal, but steel mill companies are attempting to use low-rank coal as an energy source in PCI combustion blast furnaces because of the increasing cost of high-rank coal and decreasing reserves. The purpose of this investigation was to determine how the coal rank is correlated to the pulverized coal particle temperature and CO emission. This study was performed using a Laminar Flow Reactor (LFR), which represents the combustion environment of pulverized coal inside a blast furnace. Since the PCI system was developed for iron making, the combustion characteristics of pulverized coal are important in the iron and steel industries. According to the different types of coals, the coal flame structure, coal particle temperature, and exhaust gases (CO and CO2) were investigated. This study demonstrated that the combustion characteristics of coal were influenced by several properties of individual coals. Primarily, the coal particle temperature and CO emission were found to have the strongest influence on the combustion characteristics of these coals. Moreover, the fragmentation phenomenon occurring in some coals was also an important factor influencing the PCI combustion characteristics. Therefore, this study significantly considered the coal properties, focusing on images of the burning coal particle flames, the particle temperature, and the CO/CO2 emissions.