BOF Gas Cleaning System Upgrades for Increased Efficiency and Off-Gas Quality

摘要

In BOF steelmaking, conditions and composition of the gas produced is varies from the start to the end of a blow. During the blow, gas with high temperature (≥ 950°C), loaded with dust (70 - 200 g Nm~3) and typically composed of approx. 90% CO and 10% CO_2 is produced at the BOF mouth. This gas has to be cooled and cleaned (down to a dust level of < 20 mg/Nm~3) before further processing downstream. Process equipment is installed above and alongside the converter mouth to enable energy recovery as well as collection and recycling of the dust produced. This article presents a newly developed technology based on annular gap scrubbers for converter off-gas cooling and cleaning with minimum maintenance requirement and increased efficiency when compared to traditional systems based on flap venturi scrubbers. In addition, an improved three-stage mist eliminator design is discussed. Both these developments are the result of applying technology developed for and proven in blast furnace ironmaking within the context of basic oxygen steelmaking.