Blast furnace injection for minimizing the coke rate and CO 2 emissions

Abstract

The tuyère injection is one of the key tools to exhaust the blast furnace potential and to minimize its CO₂ emissions. The review argues theoretical basis and operation strategies for ensuring the high efficiency of injection of auxiliary reducing agents (ARA). First, it provides the theoretical analysis of requirements that ensure minimum coke and carbon rates, and minimum CO₂ emissions. Then it focuses on the injection of selected ARA, such as pulverized coal, biomass products, and hydrogen containing gases – natural gas, coke oven gas and pure H₂. Conversion behaviour of mentioned ARA and measures for its intensifying are discussed critically. Next, compensating measures and their suitable level are discussed. The role of oxygen and ways for its introduction are discussed from different points of view. Operating windows and co-injection of solids and H₂ gases are discussed aiming at the best blast furnace performance. Finally, limiting factors for injection of ARA are summarized.