Abstract
Blast furnace (BF) ironmaking is the most important process that produces hot metal (HM) from iron-bearing materials continuously, rapidly, and efficiently. To date, the process is considered to have reached its limit in view of the achieved high process efficiency. In addition, the required high-quality materials are expensive and gradually getting depleted. Hot gas injection (HGI) into the shaft of the BF is an emerging technology recognized potential to solve the aforementioned problems. However, so far, limited information and studies are available, most of which are preliminary studies with regard to the feasibility and aerodynamics of the technology. This hindered the understanding and thus the effective use of this technology. This work presents a numerical study of the multiphase flow, heat, and mass transfer in a BF by a CFD-based process model. The effects of injection composition in terms of CO and CO2 contents in HGI are studied first. The calculated results reveal that HGI of 100% CO delivers the best BF performance. Then, the effects of key variables in relation to HGI of 100% CO, including position, rate, and temperature, are systematically studied. The in-furnace states and overall performance parameters have been analysed in detail. The results show that, through appropriate control of the injection variables, it is possible to achieve improved BF performance including low fuel rate and high productivity, which are considerably affected by the HGI parameters. The BF process model is also demonstrated to be a cost-effective tool in optimizing the key variables of HGI in BF for obtaining optimum process efficiency.
Highlights
Blast furnace (BF) ironmaking is the most important process that produces hot metal (HM) from iron-bearing materials continuously, rapidly, and efficiently
In addition to the in-furnace solid temperature for the BF without Hot gas injection (HGI) and with different HGI being represented by flooding, the lines representing the solid temperature for the base operation (BF operated without HGI) are added to all the cases considered for comparison
Compared with the BF without HGI, the solid temperature is higher in the upper furnace with HGI regardless of the injection composition, which suggests that heat energy is supplied to the upper furnace and HGI operations result in more severe cooling losses of heat from the wall [57]. e simulation result is in line with the previous study [23] based on an experimental BF (EBF) with injection of hot reformed gas
Summary
Computational Study of Hot Gas Injection (HGI) into an Ironmaking Blast Furnace (BF). Mathematical Problems in Engineering examined at various levels and proved to be useful for improving BF performance Among these technologies, the hot gas injection (HGI) into the BF is considered useful due to its possible advantages [1, 16]. HGI is more frequently employed on the OBF as an enabling technology to address the thermal shortage phenomena in the upper furnace with several typical OBF processes established [18, 22, 24, 25, 32] It is considered as an essential part for realizing the zero-carbon footprint OBF process through injection of recycled top gas after CO2 capture and storage. Is work, for the first time, presents a comprehensive numerical study of the effects of HGI on BF performance, with respect to key performance indicators including injection composition, position, temperature, and rate. The model is modified so that it is able to handle BF with HGI with varying injection composition, position, rate, and temperature within wide ranges
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