An Update on FINEX® Technology Development

FINEX® 1.5 MTPY Plant at the Pohang Works

I. INTRODUCTION

The blast-furnace ironmaking process, which relies on the coking and sintering processes, has been the dominant hot-metal production technology for over a century due to its high productivity, and excellent heat efficiency. However, increasingly scarce raw materials, and more demanding environmental standards have created an urgent need for an entirely new ironmaking process. During the past few decades, steelmakers worldwide have pursued development of innovative new ironmaking technologies to take the place of the blast furnace. The common objective of all these new technologies has been to avoid sintering and cokemaking by producing hot metal through the direct use of fine ore and coal. Although many different projects have been initiated over the years, only a handful of technologies have made it to the demonstration scale phase. Posco initiated the FINEX® development program in 1992 in cooperation with Austrian plant-building specialist Siemens VAI. The goal of the program was to create an ironmaking process that would 1) eliminate the coking and sintering processes, 2)operate on low-grade, low-cost raw materials, and 3) be financially competitive with the blast furnace process.

Comparison of the Blast Furnace and FINEX® Processes

Following successful tests at a pilot plant starting in 1999, a 600,000-tpy demonstration plant began operation in June 2003. Based on the excellent results achieved, a 1.5-mtpy FINEX® plant has been constructed at the Pohang Works. Plant start-up was in April 2007.

II. PROCESS OVERVIEW

In the blast-furnace process, blended iron-ore fines are agglomerated at a sinter plant, and coking coal is processed at coke-ovens in preparation for use in the blast furnace.

The FINEX® process simplifies ironmaking by eliminating the sintering and coking processes. Fine iron ore is charged into the fluidizedbed reactors. As it passes through the four reactors, it is preheated and reduced. Subsequently the reduced iron ore is charged into the melter-gasifier, where it is smelted into hot metal and molten slag. Coal is processed by either a briquetter or the pulverized coal injection (PCI) facilities. Briquetted coal is charged into the dome of the melter-gasifier, while pulverized coal is injected through the tuyeres. The reducing gas generated by coal combustion with pure oxygen is channeled to the fluidized-bed reactors to reduce the iron.

III. FINEX® DEMONSTRATION PLANT OPERATIONAL RESULTS

Productivity

In the initial stage of operations, trial campaigns were carried out to verify the performance of newly installed facilities, confirm fuel and raw material characteristics, and determine optimal operating parameters. A fullscale operation got under way in January 2004 and stabilized over time at a hot-metal production level of 2,100 tons per day.

Coal Rate

Significant effort has been paid to reducing the coal rate. An important step was the start-up of the CO2 removal and off-gas recycling systems. Following installation of the systems, coal consumption fell to the 900 kg/tHM level. The next step was the adoption of pulverized coal injection (PCI). Over time the PCI rate has been gradually increased to its current 250 kg/tHM level, reducing total coal consumption to the 750 kg/tHM level.

Hot-Metal Quality

Table 1 compares the operating performance of the FINEX® demonstration plant and the Pohang No.1 blast furnace. The FINEX® hot-metal quality is similar to the blast furnace product.

Table 1: Comparison of FINEX® and Blast Furnace Operating Performance (Sept. 2006)

The alumina in FINEX® slag is higher in 17~18% range due to the use of Australian ore. The ability to operate with high-alumina ore is a key benefit FINEX® has over blast furnaces.

Environment

The environmentally friendly nature of the FINEX® process ensures it will be even more competitive in the future. FINEX® SOx, NOx, and dust emissions are a mere 3 %, 1 %, and 28 %, respectively, of those generated by the blast furnace process, enabling it to easily comply with strict environmental standards and legal regulations.

IV. CONCLUSION

The simple nature of the FINEX® process and its ability to use low-cost raw materials means that both capital investment and production costs are much lower than the blast furnace route. A 1.5-mtpy FINEX® plant can produce hot-metal more cost effectively than a modern 3-mtpy blast furnace. When oxygen and power plants are included in the comparison, the capital and operating costs of a FINEX® plant are roughly 20 % and 15 % lower, respectively, than a blast furnace.

Siemens VAI and Posco continue to develop of the FINEX® technology to enhance i ts competitiveness by fur ther reducing consumption figures. Currently all efforts are focused on achieving optimum operation of the 1.5-mtpy FINEX® plant that commenced operations in April 2007. Once this first commercial FINEX® plant has achieved a proven operating record, Posco plans to replace the small- and medium-sized blast furnaces at the Pohang Works with FINEX® plants.

Siemens VAI developed in co-operation with the South Korean steel manufacturer POSCO the FINEX-process – an alternative procedure to the blast-furnace iron-making process. In December 2006 TÜV Austria participated together with Siemens VAI and Posco in a measuring campaign related to the gas and water systems of the plant for optimization of the process and for validating of design data. The successful project execution under heavy environmental conditions provided valuable results for Siemens VAI and POSCO. The article shall give you an overview on the developed procedure for the pig iron production, in particular because in April 2007 the first industrial FINEX plant with a yearly capacity of 1.5 million tons of pig-iron started the production at POSCO Steelplant in Pohang, South Korea.

Ing. Ludwig Pointner, e-mail: poi@tuv.at