Influences of Selective Waste Gas Recirculation on the Sinter Plant Process

Abstract

Operating a sinter plant is material consuming and an energy intense process. It has vast impacts on the hot metal production and on the environment. Selective waste gas recirculation (SWGR) has been introduced to complement the sintering process to reduce energy consumption, waste gas volume and SO2 emissions. Simulating this complex process is an attractive and low-cost opportunity for testing new operational settings. The sinter plant implementation in gPROMS ModelBuilder® characterises the processes based on three sub-models. A burner model describes the ignition effects, a black box model characterises the most important sinter strand processes and a wind box model splits the total off-gas stream into a recycle gas and a stack gas. A specific temperature polynomial was developed to represent the temperature distribution over the wind boxes enabling more detailed investigations of SWGR and a stable calculation of the sinter process in highly integrated flowsheets of iron production facilities.Introducing SWGR to the sinter process, the model shows reduced coke consumption, stack gas and sulphur dioxide emissions by 11 %, 27 % and 27 %, respectively. The sinter binding capacity of SO2 has the highest influence on lowering SO2 emissions under SWGR conditions.