Analysis of Operational Parameters Affecting the Sulfur Content in Hot Metal of the COREX Process
- PDF / 1,740,022 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 51 Downloads / 195 Views
INTRODUCTION
ACCORDING to the data, a blast furnace (BF), which is a conventional ironmaking process, is still the dominant technology to produce hot metal (HM) because of its high efficiency. Nevertheless, the environmental pressures and the increasing scarcity of good quality coking coal have led to the development of alternatives to the traditional blast furnace. The COREX process has been developed as one of the most acceptable ironmaking process alternatives. It is the first industrially proven smelting reduction process that uses noncoking coal as fuel.[1,2] It consists of two reactors: the prereduction shaft furnace and the melter gasifier (Figure 1). The materials, i.e., pellet, lump iron, coke, and fluxes, are continuously charged into the reduction shaft, and the reducing gas at about 1123 K (850 C) is injected through the bustle and moves in the counter current direction to the top of the shaft furnace and exits at around 573 K (300 C). The hot DRI along with partially calcined fluxes from the shaft furnace are discharged to the top of the melter gasifier in solid state. Noncoking coal is fed into the melter gasifier and oxygen is blown through the tuyeres, which gasifies the coal and generates reducing gas and heat.[3–5] Nonetheless, the COREX process also has some disadvantages, such as the higher and more serious fluctuation of the sulfur content of COREX HM than that of the BF. It is of great necessity to investigate the operational
SHENGLI WU, Professor, LAIXIN WANG, Ph.D Student, MINGYIN KOU, Lecturer, and YUJUE WANG and JIACONG ZHANG, Graduate Students, are with the School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, P.O.B 878, Beijing, 100083, P.R. China. Contact e-mail: [email protected] Manuscript submitted May 25, 2016. METALLURGICAL AND MATERIALS TRANSACTIONS B
parameters affecting the sulfur content in the HM of the COREX process. In this article, for a better control of S, it is of prime importance to understand the S transfer process and the various parameters that affect it. Then, a series of statistical analysis of COREX-3000 plant data have been carried out to understand the relationships between operational parameters and the sulfur content in hot metal.
II.
DISTRIBUTION AND TRANSFER OF SULFUR IN COREX
As in the BF, sulfur enters COREX through its inputs, ferrous materials, coal, coke, and flux. And it exits through its outputs, hot metal, slag, and export gas. The input and output values of sulfur in the COREX and BF processes of the same hearth diameter are calculated and compared and listed in Figure 2. Based on the sulfur balance, the sulfur loads are 5.84 and 2.90 kg/t for COREX and BF, respectively. The main reason is the high fuel rate of the COREX process, which is almost double that in the BF process. In the output items, the proportion of export gas carried out is supposed to be 20 pct, which is 10 pct for BF. This hypothesis is based on the theory that the volatiles of coal decomposition at the
Data Loading...
