Techno-economic model of Methane pyrolysis in liquid metal bubble column reactor for hydrogen direct reduction of iron ore

<p>Reducing emissions from the iron and steel industry is essential to achieve the Paris climate goals.A new system to reduce the carbon footprint of steel production is proposed in this article by coupling hydrogen direct reduction of iron ore (H-DRI) and natural gas pyrolysis on the liquid metal surface inside a bubble column reactor. If grid electricity from the EU is used, the emissions would be 435 kgCO\textsubscript{2}/tls without considering methane leakage from the extraction, storage, and transport of natural gas. Solid carbon, produced as a by-product of natural gas decomposition, finds applications in many industrial sectors, including as a replacement for coal in coke ovens. The specific energy consumption (SEC) of the proposed system is approximately 6.3 MWh per ton of liquid steel(tls).It is higher than other competing technologies,3.48 MWh/tls for water electrolysis based DRI, and 4.3-4.5 MWh/tls for natural gas-based DRI and blast furnace-basic oxygen furnace (BF-BOF) respectively. The utilization of large quantities of natural gas, where the carbon remains unused, is the major reason for the high SEC. Preliminary analysis of the system revealed that it has the potential to compete with existing technologies to produce CO\textsubscript{2}free steel, if renewable electricity is used. Further studies on the kinetics of the bubble column reactor, H-DRI shaft furnace, design, and sizing of components, along with the building of industrial prototypes are required to improve the understanding of the system performance.</p>