Comparing different syngas for blast furnace ironmaking by using the extended operating line methodology
Manuel Bailera
Abstract
This paper assesses the injection of different syngas in air-blown blast furnaces, oxygen blast furnaces, and advanced oxygen blast furnaces. The selected types of syngas come from biomass gasification, plastic gasification, CO2 electrolysis, and reverse water–gas shift reaction. An Aspen Plus model, based on the new extended operating line methodology, was used for the simulation. This methodology is a generalization of the conventional Rist diagram, to extend its application to cases in which the injected gases have large contents of CO2 and H2O, and also to cases in which injections take place at the middle or upper zone of the blast furnace. The base cases were elaborated and validated with data from literature, with a discrepancy below 3.5%. A total of 7 key performance indicators were defined for the study (mass flow of syngas, coke replacement ratio, gas utilization, percentage of direct reduction, blast furnace gas temperature, flame temperature, and net CO2 emissions). In practice, the amount of syngas that can be injected is limited to 92 – 264 kgsyngas/tHM because of the drop in the flame temperature. The lowest net CO2 emissions are achieved in oxygen blast furnace with injection of syngas from reverse water–gas shift reaction.