A REENGINEERED DR PLANT FOR QUALITY, LOW-COST ONSITE DRI PRODUCTION

Raul Quintero HYL – Technology from Hylsamex

Presented at the ISSTech 2003 Conference April 27-30, 2003

Indianapolis, Indiana

Key Words: DRI, HBI, Metallics, Mini-Module, HYL Self-Reforming Process

INTRODUCTION

Over the course of the past 15-20 years, the developments in the field of direct reduction technology have been dramatic, although as with most markets, with highs and lows in activity. What had been consistent however was the continuous improvement in technology and the escalation of plant sizes. Technology suppliers made great advances in pushing process development to reach low energy consumption levels and to improve DRI quality to the point where it is currently the premium value-added iron source for electric furnaces. This increased product quality, as well as the development of hot briquetting technology, made DRI a commercial commodity. Plant sizes began to increase in order to achieve a low dollar per metric ton investment cost as well as to satisfy the demand for increased volumes of the products. By the late 1990’s, DR plant sizes of one-million mtpy capacity became the norm and single plants with capacities exceeding 1.5 million mtpy were extremely common. The downturn in the steel industry of the past few years has brought about lower steel prices, company closings and consolidations, and companies are in survival mode rather than expansion. This has affected the direct reduction plant segment of the industry, since there were no low cost options available to interested steel minimills for installing DRI capacity onsite. This paper deals with the work completed by HYL and Ferrostaal AG to develop a solution for providing low cost onsite DRI production for steel makers.

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INTEGRATION OF A DR PLANT IN A MINIMILL The first DR plants to achieve industrial and commercial success were smaller capacity plants built onsite to provide virgin iron units for electric furnace steelmaking. As technology advanced, DR plants became not only more sophisticated, but capacities grew as well. The commercial success of DRI helped bring the industry to the point where the typical steel producer could not manage the investment required for installing onsite direct reduction capacity. HYL, together with Ferrostaal AG of Germany, decided to rethink the concept of a DR plant based on current market conditions. Upon analyzing the needs for DRI, company management and engineering went back to the original justification that led to Hylsa’s first direct reduction technology and plants nearly 50 years ago. For steel mills, an integrated DRI facility presents the following advantages: DRI is available onsite, allowing steel production to be less dependent on prevailing market fluctuations

and conditions relevant to the metallics. Liquid steel quality is improved by the availability of DRI, enabling the minimill to meet any finished

product specification. DRI production rate can be tailored to meet the requirements of the minimill and avoid financial

participation and off-take commitments in external high capacity DRI plants. The challenge was to come up with a DR plant configuration that would allow the above advantages at an investment cost that was within the reach of the typical steel producer. As a result, HYL and Ferrostaal have developed an optimized concept for a low investment cost DR plant with a capacity range of 0.3-0.5 mmtpy. This plant size has been selected to cover the widest range of situations for onsite DRI production. The integrated optimized plant in which DRI is produced economically onsite has been denominated the HYL Mini-Module.

ADVANTAGES OF THE MINI-MODULE DESIGN Besides the advantages for a minimill of an integrated DR plant, the HYL Mini-Module concept presents features that have a positive impact on both operating and investment costs. Among these features are: Low investment cost. Adapting the latest developments and improvements of the HYL Technology, based on the Self-reforming process scheme, has significantly reduced the specific capital investment.

Small plant size. As mentioned above, the DR plant size is of 0.3–0.5 mtpy, which is an ideal size to fulfill the typical metallics requirements of most minimills for a wide range of steel products.

Optimized process design. Specific optimization of process parameters, as a result of the industrial operation of the Hylsa 4M DR plant, has been incorporated in the design of the HYL Mini-Module.

Prefabricated equipment (skid-mounted, modular design). There has always been an economic compromise between prefabricated equipment and erection time. For big plants, to transport prefabricated equipment is not

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