Top Gas Recycling Blast Furnace Process Mar09

Top Gas Recycling Blast Furnace Process...

Top Gas Recycling Blast Furnace Process In the area of production of hot metal (HM) by blast furnace (BF), the most promising technology to significantly reduce the CO2 (carbon di-oxide) emission is recycling of CO (carbon mono oxide) and H2 (hydrogen) from the gas leaving the BF top. CO and H2 content of the top BF gas has a potential to act as reducing gas elements, and hence their recirculation to the BF is considered as an effective alternative to improve the BF performance, enhance the utilization of C (carbon) and H2, and reduce the emission of CO2. This ‘top gas recycling’ (TGR) technology is mainly based on lowering the usage of fossil C (coke and coal) with the re-usage of the reducing agents (CO and H2), after the removal of the CO2 from the top BF gas. This leads to lower the energy requirements. Because of the advantages of high productivity, high PCI (pulverized coal injection) rate, low fuel rate, and low CO2 emission etc., the TGR-BF process is considered to be one of the promising ironmaking processes in future. In TGR-BF, oxygen (O2) is blown into the BF instead of hot air to eliminate nitrogen (N2) in the top BF gas. Part of the top BF gas containing CO and H2 is utilized again as the reducing agent in the BF. CO2 from the BF top gas is captured and then stored. Several recycling processes have been suggested, evaluated or practically applied for different objectives. These processes are distinguished by (i) with or without CO2 removal, (ii) with or without preheating, and (iii) the position of injection. The concept of the TGR-BF (Fig 1) involves many technologies which include (i) injection of reducing top BF gas components CO and H2 in the...