Ammonia as a Green Energy Carrier to Lower Blast Furnace CO₂ Emissions

Green hydrogen is seen as crucial for the decarbonisation of the economy. Yet, some regions may lack local producing capability, necessitating hydrogen imports. Ammonia can be a cost-effective solution to indirectly transport hydrogen. Three concepts are presented for using ammonia as reductant in the Blast Furnace (BF) process. The first concept, called EASyMelt shaft, incorporates cracked ammonia into the furnace’s shaft. The second concept, NH₃ EASyMelt, takes the changes a step further and injects cracked ammonia in both the bosh and shaft tuyeres. The cracked ammonia, heated by plasma torches, replacing hot blast and coal in the bosh tuyeres. Finally, NH₃ EASyMelt is implemented with top gas recycling (TGR). The furnace operation under these scenarios is compared to conventional operation using a multi-phase BF process model. The CO₂ emissions are found to be reduced by 15% for EASyMelt shaft, 60% for NH₃ EASyMelt without TGR and 55% with it. The new concepts are also shown to have a significant impact on the thermal state, gas distribution, pressure drop and cohesive zone characteristics. The study sheds light on how ammonia could be integrated into the BF process, and the expected impact on the furnace thermochemical state and the CO₂ emissions.