Comparison of Energy Consumption and CO2 Emission for Three Steel Production Routes—Integrated Steel Plant Equipped with Blast Furnace, Oxygen Blast Furnace or COREX

High CO2 emissions and energy consumption have greatly restricted the development of China’s iron and steel industry. Two alternative ironmaking processes, top gas recycling-oxygen blast furnace (TGR-OBF) and COREX®, can reduce CO2 emissions and coking coal consumption in the steel industry when compared with a conventional blast furnace (BF). To obtain parameters on the material flow of these processes, two static process models for TGR-OBF and COREX were established. Combining the operating data from the Jingtang steel plant with established static process models, this research presents a detailed analysis of the material flows, metallurgical gas generation and consumption, electricity consumption and generation, comprehensive energy consumption, and CO2 emissions of three integrated steel plants (ISP) equipped with the BF, TGR-OBF, and COREX, respectively. The results indicated that the energy consumption of an ISP with the TGR-OBF was 16% and 16.5% lower than that of a conventional ISP and an ISP with the COREX. Compared with a conventional ISP, the coking coal consumption in an ISP with the TGR-OBF and an ISP with the COREX were reduced by 39.7% and 100% respectively. With the International Energy Agency factor, the ISP with the TGR-OBF had the lowest net CO2 emissions, which were 10.8% and 35.0% lower than that of a conventional ISP and an ISP with the COREX. With the China Grid factor, the conventional ISP had the lowest net CO2 emissions—2.8% and 24.1% lower than that of an ISP with the TGR-OBF and an ISP with the COREX, respectively.

Experiment Research on Pulverized Coal Combustion in the Tuyere of Oxygen Blast Furnace

The actual combustion rate of pulverized coal in the blast furnace tuyere is hard to be measured. In this research, the combustion rate of pulverized coal injected into oxygen blast furnace was obtained by a new equipment. This equipment can simulate the actual blast furnace well, and the relationship between pulverized coal injection (PCI) ratio and AO/C was established by mathematical deduction. The experimental results show that the best combustibility of the four pulverized coals is C, and when the coal injection ratio is 350 kg/tHM, the combustion rate can be reached 79%, while the combustion rate of B in the same case is only 45.6%. With the increase of AO/C, the relative amount of oxygen to coal increases, the combustion conditions become better, and combustion rate of the pulverized coal increases. In addition, under the condition of high temperature and rapid combustion, with the increase of coal’s volatile, the combustion rate increases and the corresponding PCI ratio is also increased. By using the new equipment, the unburned coal under the oxygen blast furnace conditions can be collected for further study.